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NA1 5-speed Transmission Rebuild Thread

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-Is the countershaft lock nut 40mm or 32mm? Every parts site I look at for 90201-PR8-000 says it's a 32mm nut.

The countershaft nut is 40mm.

-Is there a flat on the countershaft to clamp with the vice to torque the new nut on? With the hollow shaft it seems iffy to clamp on the thinner parts.

There is no flat on the countershaft, you have to clamp the bottom gear that drives the ring gear in a vice between two blocks of wood. I'd recommend an impact gun to remove the nut.

-The factory SM says the torque sequence for the countershaft nut is 116->0->116 lb-ft, so it's meant to be torqued fully, taken off, then torqued again and staked? Didn't see that mentioned here.

I believe that's how it works.

-For your improvised "diff inspection tool", is it just some 10"+ all-thread that's double-nutted with washers on either side to clamp against the inner diff shaft inside of the tapered bearings? I assume the washers are doing the clamping since the diff splines aren't engaged to anything.

I used a long bolt I found at Home Depot. Something I thought of after the fact though, I would actually recommend you figure out some way to engage the splines instead though as theoretically the bolt could compress the differential housing enough to throw off the preload reading. If you use the bolt method, tighten it as little as possible, you only need to support like 30inlb.

-Reading through this and some other threads, I'm a bit unclear on the mainshaft thrust clearance procedure. This is what I gleaned for the procedure without the mainshaft holder tool:
1) Fully assemble mainshaft with both ball bearings, oil guide plate & original thrust shim(s) into housing (assuming it is the proper thickness, can be changed after first clearance measurement)
(OPTIONAL: leave thrust shim out, then subtract shim thickness from final clearance in last step to get a more accurate total clearance reading)
2) measure spring washer with micrometer, leave OUT of case
3) install mainshaft into housing, torque the case halves together
4) room temp, mainshaft oriented vertically, dial gauge on the mainshaft, zero, and pull shaft in & out to get a clearance reading (this clearance - spring washer thickness = 0.14-0.21mm according to FSM)
5) if (measured clearance - spring washer thickness) is NOT = 0.14-0.21mm, take mainshaft out again and upsize/downsize the thrust shim as needed
(i.e., if clearance without spring washer is 1.08mm, spring washer measures 0.82mm, final clearance is 0.26mm, so upsize thrust shim one size (+0.05mm) which would give ((1.08mm-0.05mm) clearance - 0.82mm spring = 0.21mm final clearance, on the upper edge of 0.14-0.21mm? Could go up another +0.05 thrust shim to land at 0.16mm)

Just looking for a sanity check of the above. I'm not planning on getting the mainshaft holder tool, and I read you can't measure the clearance with the spring washer installed without it since the washer needs to be compressed properly.

Thank you for asking this question, because I went back and read what I wrote, and it's little better than gibberish to me now that it's not all fresh in my mind, so not exactly a good explanation for someone who hasn't done it before, so I'll try to explain better.

The mainshaft shim selection procedure is two parts.

1) Select the appropriate shim thickness

What the service manual procedure does is measure the play in the mainsheet without the shim or spring washer, and use that to calculate allowable range of shim sizes. On page 13-41 you can see this process, and its rather crude. This process results in a value that you then subtract 0.99mm (0.0390") from to get the maximum shim thickness, and subtract 1.06mm (0.0417") to get the minimum shim thickness, then from this you can purchase the correct shim(s) to get you within that range.

The better way to find this measurement is to assemble the mainshaft, remove the thrust shim/spring washer/oil guide plate, then install the mainshaft and bolt the case halves together, and measure the the clearance with a dial indicator at the end of the mainshaft. You can then compute the desired shim thickness range using the values above and figure out what shim(s) you need to buy.

2) Confirm that the mainshaft has the correct clearance with the new shim

The second part of the process occurs after the correct shim thickness has been selected using the above method, and ensures that the mainshaft has the correct amount of movement with the spring washer installed. The service manual procedure uses a special mainshaft holder and a dial indicator to measure the travel of the mainshaft as the spring washer compresses, but we can approximate this measurement just by measuring the spring washer thickness.

When fully compressed, the spring washer is flat, so the thickness of the spring washer when fully compressed is the same as the thickness of the washer material when fully uncompressed (at least close enough for our purposes). To do this, install the mainshaft with the oil guide plate and shims, but WITHOUT the spring washer and bolt the case halves together, then measure the end play using a dial indicator. Finally, subtract the compressed thickness of the spring washer from this measurement, and you'll have your thrust clearance. The resulting value should be between 0.14mm (0.0055") and 0.21mm (0.0083"). If you measured everything correctly then you should hit it first try, if not, adjust the shim thickness and try again.
 
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Great, thank you for the extra info. I'll pick up a 40 mil socket then. Hopefully my 1/2" impact will do the job.

Interesting thoughts on the diff tool. Since the OEM diff inspection tool is discontinued or >$100 each if you search enough, maybe I could buy a cheap aftermarket CV axle to hack up and fit in the splines :biggrin:. You can get a Surtrack axle for $50, cut off the outboard splined end from the roller joint hub & deburr it, use the axle nut for the torque wrench and use the rest for a bedside lamp. If you get the left-hand axle (without the female splines for the intermediate shaft), suddenly you have both diff tools for 1/4 the price since you can use the inboard hub as the bottom holder tool. Am I crazy?

While I'm on the topic, I read another article where the rebuild shop struck the diff bolt heads with a hammer & punch after initial torquing to "relax" the bolt threads before final torquing, but this isn't in the service manual. Should red loctite be used as well?

...

Thank you for asking this question, because I went back and read what I wrote, and it's little better than gibberish to me now that it's not all fresh in my mind, so not exactly a good explanation for someone who hasn't done it before, so I'll try to explain better.

The mainshaft shim selection procedure is two parts.

1) Select the appropriate shim thickness

What the service manual procedure does is measure the play in the mainsheet without the shim or spring washer, and use that to calculate allowable range of shim sizes. On page 13-41 you can see this process, and its rather crude. This process results in a value that you then subtract 0.99mm (0.0390") from to get the maximum shim thickness, and subtract 1.06mm (0.0417") to get the minimum shim thickness, then from this you can purchase the correct shim(s) to get you within that range.

The better way to find this measurement is to assemble the mainshaft, remove the thrust shim/spring washer/oil guide plate, then install the mainshaft and bolt the case halves together, and measure the the clearance with a dial indicator at the end of the mainshaft. You can then compute the desired shim thickness range using the values above and figure out what shim(s) you need to buy.

2) Confirm that the mainshaft has the correct clearance with the new shim

The second part of the process occurs after the correct shim thickness has been selected using the above method, and ensures that the mainshaft has the correct amount of movement with the spring washer installed. The service manual procedure uses a special mainshaft holder and a dial indicator to measure the travel of the mainshaft as the spring washer compresses, but we can approximate this measurement just by measuring the spring washer thickness.

When fully compressed, the spring washer is flat, so the thickness of the spring washer when fully compressed is the same as the thickness of the washer material when fully uncompressed (at least close enough for our purposes). To do this, install the mainshaft with the oil guide plate and shims, but WITHOUT the spring washer and bolt the case halves together, then measure the end play using a dial indicator. Finally, subtract the compressed thickness of the spring washer from this measurement, and you'll have your thrust clearance. The resulting value should be between 0.14mm (0.0055") and 0.21mm (0.0083"). If you measured everything correctly then you should hit it first try, if not, adjust the shim thickness and try again.

This helps out a lot.

Essentially, your step 1 includes my "optional" step without the thrust shim, and the only difference is leaving out the oil guide plate and using the factory formulae on pg. 13-41 like you say, which assumes no thrust shim, spring washer, or oil guide plate.

Your step 2 seems to match with my steps 2-4, so I think I understand everything properly now.

In theory, since I would only be replacing the countershaft with the 4.23 version and the mainshaft will remain the same (assuming the spacer collar isn't changed), I would think there's a good likelihood that the already installed thrust washers will give the correct clearance assuming they were already sized correctly. Obviously I would check & get a new thrust washer if necessary, just a thought.
 
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Great, thank you for the extra info. I'll pick up a 40 mil socket then. Hopefully my 1/2" impact will do the job.

Interesting thoughts on the diff tool. Since the OEM diff inspection tool is discontinued or >$100 each if you search enough, maybe I could buy a cheap aftermarket CV axle to hack up and fit in the splines :biggrin:. You can get a Surtrack axle for $50, cut off the outboard splined end from the roller joint hub & deburr it, use the axle nut for the torque wrench and use the rest for a bedside lamp. If you get the left-hand axle (without the female splines for the intermediate shaft), suddenly you have both diff tools for 1/4 the price since you can use the inboard hub as the bottom holder tool. Am I crazy?

While I'm on the topic, I read another article where the rebuild shop struck the diff bolt heads with a hammer & punch after initial torquing to "relax" the bolt threads before final torquing, but this isn't in the service manual. Should red loctite be used as well?

My 1/2 impact worked on the 40mm nut with no issues, I imagine you'll be fine.

Using something like this would be a lot easier (and cheaper) than hacking up an axle.

5701252_rnb_02600_pri_larg.jpg


I've never heard of whacking bolts to relax the threads, the service manual also does not call for loctite.
 
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Ah, I was thinking of the breakaway/preset torque measurement on pg. 15-4 rather than the bearing preload measurement on pg. 15-13.

I see what you mean in that the preload only requires up to 26 lb-in torque, so I can see how a rubber stopper would be enough to hold the splines in place. The only thing is if the rubber is on the softer side, it might compress slightly when checking torque and throw off the measurement as well, unless you really cranked on that nut to compress the rubber down beforehand. Either way, I need an even smaller torque wrench since 26 lb-in is below my 1/4" clicker wrench.

I was thinking you'd need a splined shaft to check the breakaway torque, especially with the NSX-R diff spring. It would be easy to do the on-car check on pg. 15-4, but if you wanted to bench test before reassembling the trans then wouldn't you have to apply 100+ lb-ft in a vice to check the proper preset? I doubt the friction between the rubber and splines would hold in that case.
 
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Yeah the rubber definitely won't hold for checking the breakaway torque (also wouldn't work as you would need to engage the splines not just the diff casing), I thought you were talking about bearing preload.

I didn't bench test the breakaway torque until after assembly.
 
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Ah, I was thinking of the breakaway/preset torque measurement on pg. 15-4 rather than the bearing preload measurement on pg. 15-13.

I see what you mean in that the preload only requires up to 26 lb-in torque, so I can see how a rubber stopper would be enough to hold the splines in place. The only thing is if the rubber is on the softer side, it might compress slightly when checking torque and throw off the measurement as well, unless you really cranked on that nut to compress the rubber down beforehand. Either way, I need an even smaller torque wrench since 26 lb-in is below my 1/4" clicker wrench.

I was thinking you'd need a splined shaft to check the breakaway torque, especially with the NSX-R diff spring. It would be easy to do the on-car check on pg. 15-4, but if you wanted to bench test before reassembling the trans then wouldn't you have to apply 100+ lb-ft in a vice to check the proper preset? I doubt the friction between the rubber and splines would hold in that case.

I'm seriously considering cutting my AT intermediate shaft and grinding a flat on it to use as a diff tool.
 
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Another thing...you can't accurately measure the preload using a clicker wrench, you need a dial or beam wrench otherwise you'll never get consistent numbers. Autozone sells a small 0-90 inch-pound beam wrench for less than $20 that seems spot on when compared to my CDI dial wrench.
 
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Another question, is the Hondabond used for the case sealant supposed to be Hondabond 4 or Hondabond HT? If they both would do the job, I might go with HT for a bit more heat resistance, but I just want to be sure that HB4 is still suitable for the application.

I've got the correct beam wrenches now for the locknut and bearing preload checking. I got the cheap CV axle too for the splines so I'll see about modifying it for my purposes. There was a guy with a TIG welder at the shop this week, I should've asked him to cut off the axle stub and weld on a nut for me...
 
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Good to know, thanks. I read HB4 is not meant for metal-metal gasketing but I could've seen myself using it without knowing. I wish the naming conventions were a bit more clear, but I recall some thread on here talking about the differences between sealants. Even more tricky since the sealant called out in the FSM doesn't exist anymore.
 
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Another question, is the Hondabond used for the case sealant supposed to be Hondabond 4 or Hondabond HT? If they both would do the job, I might go with HT for a bit more heat resistance, but I just want to be sure that HB4 is still suitable for the application.

I've got the correct beam wrenches now for the locknut and bearing preload checking. I got the cheap CV axle too for the splines so I'll see about modifying it for my purposes. There was a guy with a TIG welder at the shop this week, I should've asked him to cut off the axle stub and weld on a nut for me...

Where did you get the axle?
 
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Where did you get the axle?

From Rockauto here (https://www.rockauto.com/en/catalog/acura,1991,nsx,3.0l+v6,1000843,drivetrain,cv+axle,2288). Note that only the inboard side would be useful for the diff tool since it has 31 splines and outboard has 30 splines.

If nothing else that corroborates the fact that the rear right axle between A/T and M/T are different lengths since Rockauto has different parts for each, and I assume the M/T version is a different SKU with other cars that just so happens to have the right length and spline counts. I've been told people have interchanged them without issue but when I have my axles off for their rebuilds, I will adjust the right axle to the M/T length.
 
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What are you guys using to wash all of the transmission internal parts? I keep seeing pictures of plastic tubs and parts, but no info on cleaning. I was thinking warm water and simple green solution? Scrub with a nylon brush and wipe everything down with microfiber towels? I am concerned about corrosion of the bare metal, so I was thinking of heating with a heat gun to quickly bake off any moisture.
 
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I have a gallon of WD40 cleaner & degreaser. Haven't gotten to the cleaning stage yet but I'll probably bathe the parts in that, scrub with a nylon brush as you said, wipe off with low-lint microfiber, blow off with compressed air and some brakleen to get rid of degreaser droplets and lint, and then put on a light coat of transmission oil or assembly lube right after the wipe-down and put in a new ziploc-type bag until assembly. For the gears that the FSM calls out to install un-oiled I'll probably just wipe off the splines with a clean microfiber right before installation.

I don't think a heat gun would be necessary if you give the parts a good wipedown with oil after blowing them off, and using any plain water & heat will probably cause some flash rusting. Water & simple green would be fine for the exterior casing but I wouldn't use on the ferrous internals. There are some rust inhibitor additives for a water/soap wash like this (http://www.partwasher.net/s.nl/it.A/id.804/.f) but that seems like more of a commercial volume shop thing. EDIT: I think this is a bit overly cautious after doing my own cleaning, but good old degreaser and brakleen afterwards to get rid of residue seems to work great.

For the main & countershafts I bought some long flexible bristle brushes to stick down inside the hollow shafts and get the gunk out, probably also while bathed briefly in degreaser. The splined end section of my mainshaft has a lot of visible gunk inside so I'll be taking my time cleaning & blowing debris out, and cleaning off all the little oil passageways and holes on the shafts too. That's why I think compressed air would be important for both debris removal and getting excess cleaner off, and oiling the cleaned parts for protection from rust.
 
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I'll post some "pro" tips I learned from doing this rebuild myself in case it might help a future Primate with their transmission rebuild. In no particular order.

Useful pages besides this thread:
http://www.nsxcb.co.uk/showthread.php?14344-My-gearbox-revision-thread
http://www.nsxprime.com/forum/showt...derations-for-older-cars-or-high-mileage-ones
http://www.nsxprime.com/forum/showthread.php/161057-nsx-r-diff-conversion
https://honda-tech.com/forums/trans...ansmission-teardown-rebuild-tutorial-2443459/ (not an NSX trans but might have useful tips)
https://www.nsxprime.com/FAQ/Reference/tsb/92-022.htm (breather tube location TSB)
https://www.nsxprime.com/FAQ/Reference/tsb/93-010.htm (infamous snap ring TSB)

-Buy a full 20 ton press or something just to do this job if you don't have one already, the money spent is worth it to facilitate assembly & disassembly, along with press plates ~3/4-1" thick at most. It really makes most of it pretty trivial. Maybe you could return it after use :wink:. I did not find a gear puller to be at all necessary.

-You only need two press tools: About a foot long each PVC pipe of 1 1/4" and 1 1/2" nominal inside diameter. They allow proper pressing on the inner races of the bearings & gears to avoid damaging them. Have some sort of sturdy aluminum or nylon puck to protect the top/bottom of the shafts during pressing will be nice to avoid gouging the ends. The PVC pipe will likely explode long before damage is done to the shafts if you happen to press too hard. Nothing in the trans should require that much force.

-Get a seal driver kit, can be used both as great press tools or for their actual intended purpose. Cheap on Amazon.

-Get a bearing splitter & puller kit, will save both time & money for certain bearing removals (ISB, differential taper bearings). Cheap on Amazon.

-Get a dial indicator for mainshaft thrust clearance, a micrometer and/or caliper for thickness measurements, feeler gauges for other clearances, and a dial depth indicator if rebuilding the differential.

-Straight snap ring pliers are required. Also need a 12pt 10mm socket for differential housing bolts.

-The 40mm socket I bought did not fit the 40mm countershaft lock nut, instead I bought a cheaper 12pt 1 5/8" socket which worked well with an electric impact and with a torque wrench. Use a new locknut and spring washer.

-Get a drawer organizer or slide-close plastic bags to label and organize parts during disassembly.

-Take plenty of pics & videos of disassembly to help with reassembly, especially for the orientation of the sleeves/hubs and bearings which are unidirectional. Spring washers also have a specific orientation, usually concave side facing down. Make sure all synchros, especially the countershaft dual cone synchro, have all their tabs aligned properly before pressing on the shafts.

-I clamped the countershaft in a fairly small 4" vice with two nylon vice guards on the side as an alternative to wood blocks, worked just fine and was able to get to the 112 lb-ft torque spec fairly easily. Follow the FSM, tighten to 112, zip off, and tighten again. Check clearances per the FSM then stake the nut, it would be good to check them before disassembly to be able to compare measurements.

-Most of the shaft parts were slip fit, the only parts that needed pressing were the mainshaft clutch side bearing (very tight, mfg name faces AWAY from shaft splines) and the countershaft 3/4/5th gears. The hubs & other parts were slip fit or loose press fit such that light hammer tapping was enough. Might not be true for all transmissions.

-Mainshaft thrust clearance can use up to 2 thrust shims, not limited to just one if you need extra thickness. Should probably be checked any time the case is opened.

-Differential bearing preload can be checked with a 1 1/4" rubber expansion plug/freeze plug shoved inside the diff splines as Motormouth suggested, but will not work for checking breakaway torque since both ends of the diff splines need to be engaged. The spline opening is about ~1 1/4".

-Gasket remover like Permatex left on the flanges for 15-30 mins and a plastic scraper work well enough to get most or all of the old sealant off without damaging the machined faces. Roloc discs or similar could probably be used but are less safe for beginners like me. Brass brushes work great too as Motormouth says.

-Assembly lube (like Redline) is good for lubrication of the new bearings & thrust surfaces, it is also thicker than normal MTF and is less likely to spread around and contaminate the Hondabond sealant during case reassembly. They make a liquid type closer to the viscosity of MTF which I would use instead of the paste type to avoid any potential issues.

-Degreaser is fine to wash & wipe off parts with, then blast with brakleen to remove degreaser residue, wipe clean with new rags/towels, blow with compressed air, and coat with a small amount of MTF or assembly lube.

-Blast the inside of the mainshaft & countershaft with cleaners until the fluid comes out clean, can use some long bristle type brushes to shove inside and loosen up any dirt as well.

-Inspect every tooth on all the gears and hubs/sliders for abnormal wear, chips, etc. especially on the engagement teeth of the gears, especially if those gears were grinding when driving. Be ready to replace the hubs/sliders and gears in addition to the synchros if they look too worn out, namely the engagement teeth being rounded off and not pointy like the FSM shows on pg. 13-35. Also consider replacing the release bearing guide if it has obvious grooves and wear.

-Disassembly of the reverse gear set requires removal of the 3x6 spring pin, which needs to be replaced with a new one during reassembly. Also use new thrust needle bearings (x4), needle bearings (x2), and thrust washers because why not.
 
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Good tips here, I really should get a seal driver kit given how many motors I've pulled and resealed in the last 5 years. Also if you forget to document the orientation of spring washers and what not, the service manual clearly lists how directional parts should be installed.

To add to this....

Not even professionals should use roloc wheels IMO, I've seen too many gasket flanges hacked up by monkey mechanics with roloc wheels.

I also wouldn't use assembly lube in a transmission, only the fluid you intend to run, I looked into this before assembling my transmission. Transmission fluid gets changed far less often than engine oil, and the assembly oil may or may not contain things that can harm the clutch disk composites or yellow metals in the transmission since it's intended for engine assembly with a quick oil change interval after. Using assembly lube *probably* won't hurt anything but it will also have zero benefits in a transmission since they use ball bearings instead of babbit bearings that rely on an oil wedge like you'd find on a crankshaft or camshafts. Assembly lube is there to protect bearing surfaces during the first startup before oil pressure is built up.

FYI Permatex does not recommend using their gasket remover product on silicone sealants like Hondabond. I've used this stuff in the past and it's whether or not it actually does anything is dubious at best, it seems like it helps a bit on paper-like composite gaskets but for most other things it does next to nothing. I will forever sing the praises of the brass brush when it comes to removing gaskets and sealants from aluminum, I have a deck bridge I use with a 0.0005" dial indicator and I've yet to have a brass brush remove any measureable amount of material from an aluminum surface, and the original flange machining marks are usually still visible after cleaning as well.

This product is NOT recommended for use on silicone gaskets.

It's also worth noting that wear on the engagement teeth of the gears is a lot less worrisome than wear on the sleeve teeth. As long as the gear teeth are still pointy-ish on top they are good to go, as the sleeve shouldn't even come into contact with these teeth until after the synchronizers have done their work and matched the RPMs of the gear with the sleeve. I know this is just anecdotal, but my Integra's transmission had a really nasty grind in 2nd and 3rd gear before I rebuilt it and I drove it quite a bit with the grind before that. The gear teeth were worn down from all the grinding, but caused zero issues after rebuild and as far as I know the guy I sold it to is still running it. If the parts are available and you want to replace them for peace of mind that's not a bad idea, but if you can't get the parts I wouldn't worry too much.
 
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The lube I got from Redline (https://www.redlineoil.com/Content/files/tech/liquid_assembly_lube_prod_info.pdf) says OK for transmissions & diffs, but I did use standard MTF on the diff clutch pack. Supposedly is similar to MT-90 and blends in during startup, so it is slightly thicker than the standard MTF weight I believe, but the total amount used during assembly should be negligible vs. the amount of actual MTF. For me the benefits are less chance of dripping onto the Hondabond seals during assembly and the red coloring to see which parts you've oiled. More of a nice to have than a necessity.

I did see the note about Permatex on silicone gaskets; it seemed like it helped loosen the old sealant for my plastic scraper to have an easier time but I wouldn't say it was amazing at it. I think brass brushing/plastic scraping is the way to go as well.

Good to know on the gear teeth, I ended up installing new 5th gears for main & countershafts, and a new 2nd counter and 3rd main. Couldn't find the 4th gear so I left it alone. I also got all 3 sleeves & hubs and replaced them too, so my original budget was blown up but I'm going for longevity & reliability for the years ahead.

Side note, did you have any trouble ordering new shims for bearing preload & mainshaft thrust? I'm trying to get the sizes I need and 95% of the shims are discontinued or backordered indefinitely, but I managed to order two shims from the 6-speed that are probably sitting on a dusty shelf in some Acura warehouse. They're listed as superseded parts for the old shims and look to be the same spec with different lettering & thicknesses so I'm hoping they will work, seems ridiculous to have to import shims from Japan. My current bearing preload is barely anything at like 2-4 lb-in. I'm using a 1 1/4" rubber plug like you suggested and it works well.
 
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Assembly lube makes more sense in engines than in gearboxes IMHO. Clean parts are the key here (both inner shafts as well). A sufficient amount of the oil you intend to use is ok. If one of the shafts is dripping wet, it's too much. :) It's recommended to change the oil after a short run (like 20 or 50 miles) anyway and check the filter too. I was glad I did when I did mine.

The only critical step where oil CAN distort the Hondabond seal is when you have to guide the shift arms/forks into position while lowering the tranny case onto the clutch case. The Hondabond is on the (lower) clutch case only. The upper case should be clean. Pretty much unavoidable that the upper case gets a small amount of oil/sweat from your hands. So a final wipe with brake cleaner on the contaminated area is recommended as soon as the shift arms/forks are in position.

The internal oil pump is driven by the final drive. So it's a good idea to have the rear tires/car up in the air, start the engine, select 1st gear and let it idle for a while with the rear wheels spinning without any load. This way the oil pump circulates the oil within the both shafts to feed the needle bearings of the gears.

Unsure if synchros esp. dual-cone do like assembly lube. Depending on the viscosity, it might be ok. If it's thick as grease it's definitely a no-go. The SM says to shift each gear a dozen times 'like a grandma'. New gearbox = drive it like new car.

Sorry to hear about the backordered status of the shims for bearing preload & mainshaft thrust. We've heard of other parts being backordered. 3.5 years ago I got all parts (and I've changed many) within two months or so. But I think a machine shop should be able to replicate them. A used shim would do too.
 
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I cross referenced various shims with the Honda USA parts catalog and was able to get what I needed through the local Honda dealer, usually in 2 days or less.

I've been extremely unimpressed with Redline transmission fluid, it made the grinding in my Integra transmission way worse than Honda MTF so I don't use their products in Honda gearboxes anymore, this is just a worthless anecdote though so YMMV. It was also unimpressive in my 540i gearbox.
 
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The lube I used is not their grease or paste type, it's still low viscosity similar to MTF. I didn't see the granny shifting section, is that in a newer manual version :confused:? Good advice though.

I'll look at some other part #'s and see if I can find something more common. All the NSX ones are gone. More so worried about the diff preload since mine was almost too low to measure even with shim N which is towards the thicker end.

Interesting, I did a bit of research on types of fluid to use and most seem to like Honda MTF, Synchromesh, or Redline MTL. Who knows how MTL will work out, I really only have like 10 hours of driving experience with manuals in the first place so I've never done experimentation with different fluids. If MTL sucks I'll probably go back to Honda MTF, like Gold said it's probably best practice to drain & fill after initial break-in as well. You have much more experience than I do so I might decide to change to Honda fluid, though my shafts are basically brand new so I don't expect to have issues yet.
 

goldNSX

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I guess I've read in the old SM about being gentle on the very first shifts in any gear with new synchros. But not sure. Anyway, it makes sense.

New shafts should be clean. I've had some residuals in them. Breakcleaner and flushing did the job. Any dirt within the shafts has nowhere to go. It can clog the oil holes or even worse: it's steamrolled by the needle bearing of the gear.

I did a complete revision 10k ago. 2 fluid changes so far and near to none 'metallic' residuals in the (dark) oil pan, so it should be fine. With new parts and streetdriving Honda MTF is the best choice.

BTW, I like the cat with the wrench. :)
 
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Question...what's the best way to seat the snap ring during reassembly after applying Hondabond? Like a dumbass, I tried hand-tightening 4 bolts on the trans case and flipping it over with the snap ring expanded to shake the countershaft bearing down into its groove like I've read on a few forum posts, and predictably some trapped oil (probably inside the diff) seeped out and contaminated my seal, plus I couldn't even get the snap ring seated right. Already scraped off the sealant, again, and left it until tomorrow. Very frustrating.

I think the next thing I'll try is using a long flathead screwdriver and wedge it under the countershaft locknut or something else robust and pry the countershaft up with the snap ring expanded to hopefully pop it in without flipping over a 150 lb transaxle. Tips are appreciated.
 

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Just flip it over after you've torqued ALL screws of the tranny case. Then check the distance of the ends of the snap-ring according to the SM. If within specs and visually ok it's ready to seal and torque the big screw plus all the other parts. No big deal.
 
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I seal up the case halves and torque all the bolts, then flip the trans over the next day (to let the Hondabond dry) to seat the snap ring and finish assembly.
 
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