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Gear shift notchiness
- Thread starter Lopaka69
- Start date
Lopaka69 said:
Does this only happen when the car is cold and just started in the morning or is it like that all the time ?
I know a few members who changed out the gear oil for gm synchro mesh and claimed the notchiness went away. Do a search to find out where to get it and which one to use specifically.
Ive used BG syncoshift before on my Eclipse Turbo's and its worked great. Those cars are known for bad syncro's and it helped big time.
I was driving a 00 NSX as a Demo and the gears felt notchy when cold but got better as it warmed up.
I was driving a 00 NSX as a Demo and the gears felt notchy when cold but got better as it warmed up.
I'll save you all the trouble of the search, I've already done it. These are the part numbers and number of bottles you will need of each...yes, mix the two products together.
GM Syncromesh Transmission Fluid part#12345349-1x (small bottle)
GM Syncromesh Fluid Friction Modified part# 12377916-2x (larger bottle)
I'm having problems shifting into 5th gear only, but only every once in a while. Be sure to call the parts department of your local GM affiliated dealership before you make the trip down there. Apparently the other import guys are onto how well this stuff works as well and it may be in short supply. I bought mine at a Chevy dealership. You should have seen the looks I got when I pulled up in the NSX and walked into parts
...priceless. My car will be in for an oil change this Friday at Keyes Acura, so I'll have the tech drain and change it then. From what I read on this sight (and a couple of others) I have no worries that this will fix the problem. Unless it's a major transmission problem.
GM Syncromesh Transmission Fluid part#12345349-1x (small bottle)
GM Syncromesh Fluid Friction Modified part# 12377916-2x (larger bottle)
I'm having problems shifting into 5th gear only, but only every once in a while. Be sure to call the parts department of your local GM affiliated dealership before you make the trip down there. Apparently the other import guys are onto how well this stuff works as well and it may be in short supply. I bought mine at a Chevy dealership. You should have seen the looks I got when I pulled up in the NSX and walked into parts
...priceless. My car will be in for an oil change this Friday at Keyes Acura, so I'll have the tech drain and change it then. From what I read on this sight (and a couple of others) I have no worries that this will fix the problem. Unless it's a major transmission problem. Attachments
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I have the notchiness when cold and the GM synchromesh helps but does not eliminate the problem. I don't know how bad it would be if I didn't live in S.CA but I just take a little extra time and be very slow and deliberate (esp. in the 1-2 and 2-3 shifts) until my car is good and warm.
I, too, have experienced notchiness in the 1 - 2 shift ever since I got my 2005 NSX. I asked the salesman from whom I bought the car about it (he's an NSX owner himself), and he told me that it's not defective and that's the way the car shifts. When I replied that my '91 NSX didn't feel that way, he responded that the six speed is a different transmission from the old 5 speed. Sometimes there wasn't any notchiness, sometimes there was, but it didn't improve perceptibly after 3000 miles, or after the car was warmed up.
In any event, just two days ago I decided to try a slightly different upshift technique. Rather than yanking/jerking the shift lever hard from first to second, I pulled it much more smoothly, with a very slight (almost imperceptible) pause in neutral before going into second. The apparent notchiness disappears when I do this, regardless of whether or not the car is warmed up.
Even shifting this way, I can still shift fairly quickly -- quickly enough so that the revs will drop when when the clutch engages second gear. In other words, I'm not shifting so slowly that the revs drop lower than the wheel speed when the clutch is released. For me, this is shifting fast enough. I'm not trying to chirp the tires on upshifts, nor do I want to be hard on the clutch.
Try it and let us know if this works for you.
In any event, just two days ago I decided to try a slightly different upshift technique. Rather than yanking/jerking the shift lever hard from first to second, I pulled it much more smoothly, with a very slight (almost imperceptible) pause in neutral before going into second. The apparent notchiness disappears when I do this, regardless of whether or not the car is warmed up.
Even shifting this way, I can still shift fairly quickly -- quickly enough so that the revs will drop when when the clutch engages second gear. In other words, I'm not shifting so slowly that the revs drop lower than the wheel speed when the clutch is released. For me, this is shifting fast enough. I'm not trying to chirp the tires on upshifts, nor do I want to be hard on the clutch.
Try it and let us know if this works for you.
my 92 is kind of tough getting from 3rd to 4th when shifting at a higher RPM. I have to use some force to get it in gear. Pausing between gears seem to help a bit.
Lopaka69 said:
I use the Redline MTL / MT-90 and it definitely results in smoother shifts after everything is warmed up. If you want to get all perspectives, you could likely spend your entire weekend reading Tranny Fluid debate threads on S2KI.
After years of reading such threads, my suspicion is that most users "notice a huge difference" not because of the type of fluid they use, but because it is often the first time they have ever changed it.
Although your vehicle is newer, you might also try ensuring proper lubrication/grease on the servicable points. It's listed in the service manual.
Sorry to bump this old topic but I feel that this is important relation information to share.
I recently switched to GM Synchromesh to solve the notchyness issue (Reading up on everyone's responses to it) and it worked amazinging but I was informed by LarryB that it was bad for the 5spd differential as he had serviced an NSX that used that cocktail tranny blend.
So I ended up going back to Honda "White cap" and all its notchy goodness. (All that tranny fluid down the drain.)
Recap: Don't use GM Synchromesh on a 5spd tranny because it wears down the differential. GM Synchromesh works well though for getting rid of the notchyness. 6spds are fine with the blend.
I recently switched to GM Synchromesh to solve the notchyness issue (Reading up on everyone's responses to it) and it worked amazinging but I was informed by LarryB that it was bad for the 5spd differential as he had serviced an NSX that used that cocktail tranny blend.
So I ended up going back to Honda "White cap" and all its notchy goodness. (All that tranny fluid down the drain.)
Recap: Don't use GM Synchromesh on a 5spd tranny because it wears down the differential. GM Synchromesh works well though for getting rid of the notchyness. 6spds are fine with the blend.
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This is the case for 1991-94 5 speeds. The 1995 up have a revised differential, and the Syncromesh cocktail is fine for those.
HTH,
LarryB
I was searching for the GM MTF parts numbers and found this thread.
After using the GM synchromesh blend on my '92 5-speed with the clutch-type LSD for about 40k miles, then Amsoil MTF for another 20k miles, then finally Honda white-cap MTF for about 5k miles, I can assure you that IS NOT the case. Perhaps that other NSX had some issues to it, but it shouldn't have been because of the GM MTF.
My LSD breakaway torque is on the high side of the SM spec, and all of my LSD clutch discs measure basically brand new... even with 128k miles total on the transmission.
See post 21 of this thread for proof:
http://www.nsxprime.com/forum/showthread.php/203689-Need-a-new-clutch-Considerations-for-older-cars-or-high-mileage-ones?p=1954314#post1954314
I'm putting GM Synchromesh back in. The transmission works the best with that fluid. Synchros are smooth as butter in all temps, there is apparently zero effect on the LSD function, and it is a synthetic blend that seems to last longer than Honda white cap MTF. The only downside is that it costs more, but it's a no-brainer to use it.
I am also using the GM synchromesh cocktail on my '95 (in the standard 2/3 regular 1/3 friction modified proportion) and I agree with other guys on here, shifting is much smoother with it, and I will never use anything else.
I'm very picky about what I use in my car, and don't use anything non-oem unless I first get a comfort level that it's better. The synchromesh cocktail was recommended by a number of experienced NSX mechanics and owners, and passes that test.
I'm very picky about what I use in my car, and don't use anything non-oem unless I first get a comfort level that it's better. The synchromesh cocktail was recommended by a number of experienced NSX mechanics and owners, and passes that test.
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Mac Attack,
Thanks for posting this. Your data would for sure discount my previous thread input. The SyncroMesh cocktail, originated well over 10 years ago, and I was cautioned then by a former NSX trained tech, no-go for the early dif. Your data certainly disputes that theory. Not quite sure I will use it with 1991-94 difs, but your data is certainly compelling.
Thanks,
LarryB
Did you mean to say 2/3 Friction modified and 1/3 regular since that's the original blend mixture?
I had originally tried 50/50 on the advice of one mechanic. Later, on the advice of another experienced NSX mechanic I went to the 2/3 1/3 ratio, and the 1/3 is the friction modified, I double-checked my work order. That is my understanding of the "standard" cocktail.
There does appear to be some confusion on the ratio, and I have seen posts where some used 2/3 of the friction modified. When I first got the car 9 years ago, one mechanic recommended straight synchromesh, no friction modified at all.
There does appear to be some confusion on the ratio, and I have seen posts where some used 2/3 of the friction modified. When I first got the car 9 years ago, one mechanic recommended straight synchromesh, no friction modified at all.
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That is intersting and also may be why there is some uncertainly. I was taught 2 friction modified/1 regular, and not to use it with 1991-94 dif. Maybe the difference is using 1 friction modifed/2 regular for the 1991-94 dif? Mac Attack: what are your ratios?
I'm pretty sure it was 2/3 FM, and 1/3 regular, but that was a long time ago and my memory isn't as good as it used to be.
I just ordered the 1/3 FM and 2/3 regular to see how it works. Local Chevy dealer wanted $23/qt so I had to buy off the internet.
Hopefully I can get the transmission reinstalled. Aligning it with the clutch is kicking my butt.
I just ordered the 1/3 FM and 2/3 regular to see how it works. Local Chevy dealer wanted $23/qt so I had to buy off the internet.
Hopefully I can get the transmission reinstalled. Aligning it with the clutch is kicking my butt.
Before using it in the NSX a long time ago, I went to HondaTech and read a lot of posts from Andrie Hartanto (remember him?) and others tracking their Honda clutch-type LSDs with the GM MTF blend. They approved so I thought I would give it a shot. Seems to work!
Larry, this discussion got me curious so I've been reading old threads. For the cocktail's proportions I've seen it go from all synchromesh regular (no FM), 2/3 synchromesh regular w/ 1/3 FM, 1/3 synchromesh regular w/ 2/3 FM, to even one with all FM!
Mac Attack, I found an old post by you saying you used 1 qt. [1/3 of the cocktail] of FM, but I'm not sure where it was, I've been jumping around.
That must have been it then, and is probably why I subliminally ordered the same for this round. :smile:
Since I've had my car for about 14 years and I'll probably just give it to the kids later, I don't really pay attention or save receipts on fluid changes. I just do them very conservatively. On my other vehicles that are dealer-serviced, I save the receipts for the future owners, go figure.
Since I've had my car for about 14 years and I'll probably just give it to the kids later, I don't really pay attention or save receipts on fluid changes. I just do them very conservatively. On my other vehicles that are dealer-serviced, I save the receipts for the future owners, go figure.
