Trans problem

[nsxtcy85]

Ok I drove the nsx yesterday like most days. Its a dailey driver in the summer and since ownership besides the clutch and regular maintnance have not had any major problems. About a year ago I started getting a slight gring into 3rd. So I looked up some fixes and it listed the Synchromesh tranny fluid. I recently have gone 10k miles on it without any problems but did not notice any significant gains.

Heres my problem. So yesterday im driving it and out of nowhere it pops out of first gear while cruising through a small parking lot. I figured I probably didnt put it in gear far enough. So I take off down the street go to second and feel a reel clunky shift. I look at the shifter and everytime im on and off the throttle while its in first or second the shift gerks back and forth especially in second. After getting home I had to back out of the driveway and then it really scared me. It seem like reverse didn't even want to work. Real chattery and gerky (the whole car). I had to keep reving and dumping the clutch slightly to get her to move.

Can someone please give me some info on whats going on?:frown:

 

[Synthesis]

could the "snap ring problem" cause this?

i also have a question - after removing my trans and putting it back in, i noticed the 5th gear synchro (which i've never had a problem with.... rarely 3rd, but NEVER 5th) seems to be going (consistently grinds into 5th when i shift above 75-80mph). why would this happen all the sudden? i'm thinking about trying the gm synchromesh solution.... think it would help in my situation?

thanks (sorry, i didn't mean to hijack your thread). could nsxtcy's problem be snap ring related?

 

[Rtype1206]

I believed Synthesis is right

The giveaway for snap ring failure is the shifter moving fore and aft in first or second on deceleration or acceleration from slow speed. This happens because when the snap ring breaks (which holds the countershaft top bearing into the case) the whole countershaft moves back and forth in the case when the direction of load / torque changes. Since first and second selector are on the countershaft, and the selector hub hooks into the selector fork which hooks into the shifters.

Most people experience a loud crunch or mechanical grinding sound as the shattered fragments of the broken snap ring grind around in the transmission.

 

[DutchBlackNsx]

Typical snapring failure. Stop driving.

 

[Chris NSX]

Typical snapring failure. Stop driving.

If it is a snapring failure, I have a 5 speed transmission for sale $1000.00 from my 6speed upgrade.

 

[nsxtcy85]

Ok I drove the car again tonight just because Im so stubborn I wanted to see what was wrong and try to diagnose something. The car didnt want to back up at all. Being the aggrivated dumb@$$ I am. Let the clutch all the way out and gave her more gas than usual. It sounded like the clutch disc was slipping pretty bad but she backed out. Reminder: This clutch usually doesn't slip at all with the aggresive grip it has. So I get out into the street and take off very easily and start going through the gears and to my disbelief its shifting fine right now. I have yet to try reverse again but the first and second are fine now..... How could this be?

 

[Rtype1206]

It possible that pieces of debris could be floating around the tranny. Do you hear rattling noises from the tranny when in neutral or in gear?

 

[nsxtcy85]

Nope no rattles at idle. That was one of the first things I listened for.

 

[goldNSX]

I would have pointed on the snap-ring as well but your last post didn't made me think so by 100%. Could be bad internals too. But anyway you'll only find it out by taking your gearbox apart. While there you have the chance to give it a full overhaul.

 

[nsxtcy85]

If im going to build it while its out can someone lead me to what im going to need and how to make it stronger than stock.

 

[goldNSX]

If im going to build it while its out can someone lead me to what im going to need and how to make it stronger than stock.

Why stronger than stock? Stock is strong enough except for the bearing at the snap-ring.

When I did mine I did ALL bearings and ALL synchros (ok, it was overkill and wasn't necessary in my case) and a new snap-ring. If you don't have the short gears that's the occasion. Depending on what is wrong with your gearbox you may need some more parts BUT you'll only see which as soon as you've opened the Pandora's box. Another owner found some shift levers to replace too.

 

[nsxtcy85]

Why stronger than stock? Stock is strong enough except for the bearing at the snap-ring.

When I did mine I did ALL bearings and ALL synchros (ok, it was overkill and wasn't necessary in my case) and a new snap-ring. If you don't have the short gears that's the occasion. Depending on what is wrong with your gearbox you may need some more parts BUT you'll only see which as soon as you've opened the Pandora's box. Another owner found some shift levers to replace too.

She will be running 10psi dailey in the spring. Thats why I want something stronger than stock. Where can I get these parts you talk about.

 

[nsxman2001]

She will be running 10psi dailey in the spring. Thats why I want something stronger than stock. Where can I get these parts you talk about.

You say 10 psi do u have a turbo on your car?

 

[goldNSX]

Where can I get these parts you talk about.

Short gears from SOS and the other ones through your dealer. Parts can be found here: http://www.acuraautomotiveparts.org...5=&systemcomp=List+All&search=All&ListAll=All those in the 5MT section.

 

[nsxtcy85]

You say 10 psi do u have a turbo on your car?

One sitting in the garage with many numerous other parts. The only major thing I need left is EMS. Once I find that for a decent price the build begins. I want a tranny that will hold the power.

 

[Synthesis]

i would think at 10psi it would be ok (don't quote me on that though).....
if not, you could get the gears cryo treated....

 

[menfou]

Hello,

I have a problem with my 1991 NSX.
1st gear
Low speed: No problem until 3-4mph
High speed : Grinding sound, cracking after 3-4mph

2nd gear
Low and High speed : No problem

3rd gear
If I am in 2nd gear at 7000rpm and I put the 3rd gear : No problem
If I am in 2nd gear at 8000rpm and I put the 3rd gear : Grinding sound, cracking

4th gear
Low and High speed : No problem

5th gear
If I am in 4th gear at 7000rpm and I put the 3rd gear : No problem
If I am in 2nd gear at 8000rpm and I put the 3rd gear : Grinding sound, cracking
If I don't want to listen grinding sound, I need to change my 5th very slowly.

I change my oil gear, I try with Honda MTF2 oil, Motul 75w90 oil and I have the
same problem.
With the Motul 75w90 oil, it's impossible to put the 2nd gear when the engine is
cold.

I think the problem is synchro 1,3,5, but it's strange to have the 1,3,5
synchros KO.
Maybe a problem with the upper fork ?
I adjsut the shift cable, but same problem

Do you have a idea ?

 

[goldNSX]

Try the new MTF3. Using ordinary gearbox oil like 75W-90 only eats up the synchros in the long run and is a big NONO. I've heard of several people using 75W-90 with one of them having to revise the hole gearbox after some time.

 

[menfou]

A friend has a NSX with 75w90 and no problem.
He can put the 1st gear at 30km/h
My trans has 110000km

 

[goldNSX]

A friend has a NSX with 75w90 and no problem.
He can put the 1st gear at 30km/h
My trans has 110000km

Believe me or not but there was a guy in Switzerland who had to rebuilt it due to 75W-90. It's like: You don't fill oil in the water system and water in the engine?

Definitly hijacking the thread: Stay away of the 75W-90 as the synchros will quit their job in the long run. There's a reason why Honda has a special gearbox oil like MTF3 and it's NOT mainly a money-related one. :wink:

 

[Larry Bastanza]

Your snap ring is broken. ANY driving with this is making things worse. Every time you drive it could be more money. There is nothing you can diagnose from the drivers seat, pull it and fix it. Did you check the trans serial number?

The 5 speed is pretty strong, you could consider cryo treatment on the gears, but I cannot confirm the improvement.

For strenthening, if require(not sure it is), contact Rob Morrison. Since he is putting down 650hp, has a ton of experience building these, he would know.

HTH,
LarryB

 

[menfou]

I change my oil with Honda MTF2 and same problem than before, after I change with Motul 75w90 and same problem.
I tried MTF3 in my Civic Type R Turbo, and I prefer 1000x the Motul.

It's not my first Honda, I know MTF oil gear, and I can say the Honda oil is good for cold(similar to 10w40) but on track this oil is very bad after 5 laps.
In my S2000 and Civic Type R, I used motul 75w90 and no problem.
A friend has a NSX and he use Motul 75w90 and no problem.

With MTF2, I break 3th synchro on my Civic Type R, then after I break the fork.
After that I break the 4th gear


I can try MTF3, but it's difficul to explain my problem, I am sure the problem is the fork and synchro

 

[goldNSX]

Pretty bad pics! Ok, tracking the car may need different oil. But tracking is Russian roulette anyway. :tongue: If you drive your car in normal conditions and don't get it away with any oil you've tried then there's certainly something wrong. :wink:

Back to the snapring: My mechanic told me that all gearboxes are prone to fail due to the snapring problem but those in the specific range will break earlier and nearly for sure.

 

[CityofAngels]

Yes, that sounds like the snap-ring has shattered. Open the inspection port on the tranny (driver's side, half-inch breaker bar/ratchet will open it) and you'll find pieces of the snap-ring sitting there. Simple to do and well worth it.

I had mine break and I replaced the tranny housing, bearings and snap-ring for around $800 in parts.

The more driving you do, the worse the gear faces will get.

/my 2 cents

 

[nsxtcy85]

Well the car has been in the garage for some time and its a confirmed snap ring. I will have a full write up about it either tonight or tomorro. Happy motoring.