I just checked my Amazon order and see that I used 2:1 FM:Regular when I refilled after changing my clutch recently. I’ve quite liked the improvement over Honda MTF.
-
Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.
Gear shift notchiness
- Thread starter Lopaka69
- Start date
Now the main question is, Did Mac Attack use 2FM and 1 Regular or 2 Regular and 1 FM for his build.
Per robbiedawg's investigation a few posts ago, it was probably 2 regular and 1 FM.
I’m about to do my fluid. How much do we need. I’ll probably do the cocktail.
I went with 2 quarts of Synchromesh and 1 quart of the Friction Modified.
Benny- How do you like it compared to the previous MTFs?
Just some observations on the 1:3 versus 3:1 versus 100: friction modified options. I am definitely not a lubrication specialist; but, did a little investigation on friction modified oils because I was looking at using a friction modified transmission oil in a vintage car transmission. For lack of a more technical explanation, the friction modified oils reduce the slipperiness of the oil which improves the operation of the synchronizer mechanism. The vendors of friction modified oils recommend against use in vehicle transaxles with LSDs; however, I have never seen them elaborate on why. Anecdotal evidence suggest that the problem is not damaging the LSD. The problem is more likely that the friction modifiers alter the engagement point of the differential, resulting in earlier engagement of LSD action. In support of this, there is a post on Prime from a few years back describing a problem with aggressive engagement of the LSD which was eventually resolved by replacing what I think was 100% FM transmission fluid with regular Honda MTL. I recall that there was no report of permanent damage to the LSD. Given the different differentials used on the NSX, the susceptibility of the LSD to the friction modified oil may depend on the model year. The take-away is that it might be prudent to start with 1/3 friction modified : 2/3 synchromesh first if you want to avoid altering the operation of the LSD. However, if you don't head off to the track or tear-ass around corners you may never notice the effect of the friction modifiers on LSD operation.
As a heads up, friction modifiers swing both ways. There are friction modifiers that increase slipperiness. I discovered this when I went to a GM dealership and asked for the fluids by name rather than part number. The parts guy came out with a small bottle of friction modifier (not 'friction modified') which apparently was for use in a limited number of specific GM LSDs. If you mistakenly put this stuff in your transmission synchro operation would likely go down the toilet. Order by the part numbers and you should get the right stuff.
As a heads up, friction modifiers swing both ways. There are friction modifiers that increase slipperiness. I discovered this when I went to a GM dealership and asked for the fluids by name rather than part number. The parts guy came out with a small bottle of friction modifier (not 'friction modified') which apparently was for use in a limited number of specific GM LSDs. If you mistakenly put this stuff in your transmission synchro operation would likely go down the toilet. Order by the part numbers and you should get the right stuff.
Excellent post Old Guy.
The safest thing to do is use what Honda recommends for the MTF - either the Honda MTF or motor oil as specified in the SMs.
However, if you experience issue with gear shift notchiness, then it may be time to experiment with aftermarket fluids.
There are two paths that depend on whether or not you have the clutch-type LSD (early models), or the non-clutch type LSD (later models). Some aftermarket MTFs are rated for use in the clutch-type LSDs, and others are not. Once again, its safest for those with the early model NSXs with the clutch-type LSD to use the aftermarket MTFs approved for that specific use.
However, for those with the clutch-type LSDs that may be a little more adventurous, there are other MTFs available for experimentation. As Old Guy said above, the specific reasons are not really documented for the common person to see. Furthermore, if you call up Amsoil or other vendors and ask, they are unwilling to say, don't know, or they just say it hasn't been tested and approved but may be fine. I do know from my research that some of the wear and oxidation packets added may not be suitable for yellow metals long-term.
With the lack of clear technical information on why a product should not be used, it then comes down to others experiences posted on the internet. It's difficult to find high-performance transaxles, and really the only information I could find was on HondaTech where I had to dig through many threads on the best MTFs. The informative stuff was from the people that tracked their clutch-type LSD-equipped cars with various fluids. I narrowed it down to those that used the stuff I wanted to (GM Synchromesh - normal and FM'ed blend), and followed their posts.
The best information specific to me was that my '92 5-speed with the clutch-type LSD was torn apart at ~60k miles for the snap-ring preventative fix, and at the same time I replaced the 1-3 synchros. Since then (fast-forward 14 years ), I've used the GM blend, Amsoil MTF, and Honda white cap for 65k miles. When I tore my transmission apart recently to replace the input shaft bearings, all of my synchros measured within spec, and even the clutch plates in my LSD basically measured new. LSD break-away torque is on the high side of the SM spec. Naturally, I filled it up with the GM Synchromesh blend as I believe it is better than the other fluids I have tried so far (Honda white cap and Amsoil).
YMMV.
The safest thing to do is use what Honda recommends for the MTF - either the Honda MTF or motor oil as specified in the SMs.
However, if you experience issue with gear shift notchiness, then it may be time to experiment with aftermarket fluids.
There are two paths that depend on whether or not you have the clutch-type LSD (early models), or the non-clutch type LSD (later models). Some aftermarket MTFs are rated for use in the clutch-type LSDs, and others are not. Once again, its safest for those with the early model NSXs with the clutch-type LSD to use the aftermarket MTFs approved for that specific use.
However, for those with the clutch-type LSDs that may be a little more adventurous, there are other MTFs available for experimentation. As Old Guy said above, the specific reasons are not really documented for the common person to see. Furthermore, if you call up Amsoil or other vendors and ask, they are unwilling to say, don't know, or they just say it hasn't been tested and approved but may be fine. I do know from my research that some of the wear and oxidation packets added may not be suitable for yellow metals long-term.
With the lack of clear technical information on why a product should not be used, it then comes down to others experiences posted on the internet. It's difficult to find high-performance transaxles, and really the only information I could find was on HondaTech where I had to dig through many threads on the best MTFs. The informative stuff was from the people that tracked their clutch-type LSD-equipped cars with various fluids. I narrowed it down to those that used the stuff I wanted to (GM Synchromesh - normal and FM'ed blend), and followed their posts.
The best information specific to me was that my '92 5-speed with the clutch-type LSD was torn apart at ~60k miles for the snap-ring preventative fix, and at the same time I replaced the 1-3 synchros. Since then (fast-forward 14 years ), I've used the GM blend, Amsoil MTF, and Honda white cap for 65k miles. When I tore my transmission apart recently to replace the input shaft bearings, all of my synchros measured within spec, and even the clutch plates in my LSD basically measured new. LSD break-away torque is on the high side of the SM spec. Naturally, I filled it up with the GM Synchromesh blend as I believe it is better than the other fluids I have tried so far (Honda white cap and Amsoil).
YMMV.
I have seen that comment before and I have always been confused by it. Honda clearly made changes to the LSD during the production run and used some different descriptions for the LSD characteristics. However, if you check the service manuals for 1991 and the post 1997 cars, the internals of both versions of the LSD look remarkably similar (there are differences); but, both versions of the LSD include a stack of clutch discs and plates. The general principles of operation would be similar and based upon the service manual description I would have expected that friction modifiers would have had similar effects on all the designs. Changes in preload between the designs and the other changes that Honda made might alter the amount of effect of the friction modifiers on LSD action. I will be up front and admit that I have never pulled apart an NSX differential so I do not have direct experience (and don't want any thank-you). I am just going from what I see in the service manual.
When people use the term non-clutch type LSD I tend to think of the Torsen , Trutrac 'box of gears' or the Quaife which is also a box of gears; but, different in some way that I have never bothered to explore. All of these definitely do not have any clutch discs at all.
Edit - for what its worth, the biggest difference that I can spot between the 1991 and post 1997 LSDs is that the cut of the gears on the carrier assembly and central gear changed from straight cut (1991) to helical (1997+) and the location of the spring plate ( giant Belleville washer) moved.
Last edited:
You are probably correct. I've never looked at the differences between the LSD versions and have just repeated what I've read on here in the past. The only thing I know 100% is my '92 5-speed that I've taken apart myself!
Sorry to pass along that misinformation. It would be nice to have a clear writeup in the wiki on the LSD designs and an updated recommended MTF list.
A little off topic, but what would you all recommend for a brand new (0 miles) 2002 tranny. I have heard of the notchiness and random 2nd gear grind when cold. What should I use and how should I break it in? TIA
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
- Joined
- 15 May 2004
- Messages
- 6,898
Baby it for the first 1'000 miles or so:
- no high revs (max. 3k rpm)
- shift it very slowly at low rpms (I've read somewhere that the very first dozen of shifts in each gear should be below 2k rpm when parts are completely new, correct me if I'm wrong)
- always shift it very slowly when the gearbox is cold, no karate-like banging.
Baby it for the first 1'000 miles or so:
- no high revs (max. 3k rpm)
- shift it very slowly at low rpms (I've read somewhere that the very first dozen of shifts in each gear should be below 2k rpm when parts are completely new, correct me if I'm wrong)
- always shift it very slowly when the gearbox is cold, no karate-like banging.
I was also referring to which fluid to use and when to change it (for break in).
Thx
Sent from my iPhone using Tapatalk
- Joined
- 15 May 2004
- Messages
- 6,898
Honda/Acura MTF
It's not necessary to change it but I did after 600 miles or so in my revised gearbox mainly to get any residual dust out of it.
Dear gents,
following this discussion quite a long time from Germany and decided to try this "cocktail" too.
Question:
The part numbers mentioned before:
GM Syncromesh Transmission Fluid part#12345349-1x (small bottle)
GM Syncromesh Fluid Friction Modified part# 12377916-2x (larger bottle)
does not seem to exist anymore.
What I could find is:
AC Delco GM Syncromesh Transmission Fluid part number 88900333
AC Delco GM Syncromesh Fluid Friction Modified part number 88900399
Are these the official subsitutes ?
following this discussion quite a long time from Germany and decided to try this "cocktail" too.
Question:
The part numbers mentioned before:
GM Syncromesh Transmission Fluid part#12345349-1x (small bottle)
GM Syncromesh Fluid Friction Modified part# 12377916-2x (larger bottle)
does not seem to exist anymore.
What I could find is:
AC Delco GM Syncromesh Transmission Fluid part number 88900333
AC Delco GM Syncromesh Fluid Friction Modified part number 88900399
Are these the official subsitutes ?
I believe they are. Those are the P/N's I saw when I last used the cocktail a year or so ago. Those other numbers are probably superseded.
Indeed - revised parts numbers
https://www.gmpartsdirect.com/oem-p...een-replaced-by-part-number-88900399-12377916
https://www.gmpartsdirect.com/oem-p...een-replaced-by-part-number-88900399-12377916
I just looked in our parts catalog and the diff's are the same. The clutch plates, disks and case are the same the only difference from 91-94 and 95-05 is the final driversion gear. The 95-05 all have the same final drive gear.
Sorry they changed the planetary gear in 95-05MT but they never changed in in the automatic it is the same as the 91-94 MT
Hope that sloves the great mystery of the difference'so in the diff's.
Sorry they changed the planetary gear in 95-05MT but they never changed in in the automatic it is the same as the 91-94 MT
Hope that sloves the great mystery of the difference'so in the diff's.
Last edited:
Hey everyone happy holidays. My shifts are noticeably better.
I have a short throw shifter kit installed so I don't have to experience the full notchy shifting into second, but the new fluid definitely allows me to slide into second gear without the notches along the way even when cold.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/201588280571
Folks I'm using my this and its better than everything mentioned in this thread so far. It is made specifically for our fussy Honda trannies. Torco is used by the U.S. military.
Prior I ran amsoil synchromesh with the gm friction modifier which was better than honda mtf.
Folks I'm using my this and its better than everything mentioned in this thread so far. It is made specifically for our fussy Honda trannies. Torco is used by the U.S. military.
Prior I ran amsoil synchromesh with the gm friction modifier which was better than honda mtf.
Has anybody else used Batman's Suggestion? What did you guys notice?
Any more details or updates for us please?
