SaabGuy

This dang S5 T2 tranny grinds 5th gear everytime; it probably dropped 5th gear syncros a long long time ago. Everytime I shift into 5th it meat-grinds and sounds like an olde skool big rig granny shifting. It never pops out or anything and all other gears feel fine. I recently put some redline lube but that only helped 1-4.


The car/tranny has 90k miles. If I had to take a guess 5th gear has been grinding for 10,000 miles or more but I've only owned the car for 8k miles.

I'm not too concerned about the cost to fix a failure; I'm more concerned about WHEN it will completely fail. I'd rather have a few failures at once such as engine, clutch, and tranny. I'd hate to rip this thing out just to have another major failure shortly after.

When is this tranny gonna completly crap out on me? Will 5th gear disapear? Will I be able to limp home? Will the floorboard nuts and bolts pop out if I hit these red buttons?

Aaron Cake

iTrader: (1)

It will likely run nearly forever. Just a bad syncro. If you rev-match it you can avoid the grind.

SaabGuy

HMMM rev matching like an old Model T at highway speeds, not fun.

My mom had a Meat grinder and it didnt last very long, but she usually shops at walmart...

Anyways, what is the final destruction point for 5th gear on this transmission? I mean, the grinding has got to be wearing something down to the point of complete failure. Will 5th gear eventually pop out? disapear? wha?

Black91n/a

Change the fluid. That'll help, and depending on what you use it could stop, or at least minimize the grind. Also try modifying your technique, that could help too. Redline MT-90 works pretty well.

SaabGuy

I replaced the fluid about 10 months ago and tried out Redline's new formula 75w90 NS which should actually help our transmission syncros a bit better than MTL or MT90 IMO. It helped al gears except 5th and I have no clue what kind of fluid was in there before.

yozsi

rev matching is hard? hell, i usually never use my clutch except in 1st and reverse.

Acesanugal

iTrader: (5)

I'm very surprised no one has suggested Double-Clutching yet?

On modern transmissions, which are all equipped with Synchronizers, this is not necessary. But it will reduce the wear on the synchronizers regardless because it makes them useless.

Practice this a bit with the car switched off...in your driveway first to avoid confusion and a nasty nasty mistake.

When you go for fifth, disengage the clutch.
Move the gear lever into Neutral (from Fourth, obviously) and engage the clutch.
Push the clutch in again and move the gear lever into Fifth.
Engage the clutch.

This matches the speed of the gear you desire (5th in your case) to the speed of the input shaft driven by the engine.

This is also useful for downshifting, but that requires that you rev-match.

Hesh

iTrader: (1)

defective rear gear box mount cause something like that but when reverse. even when in driveway stopped (engine running), I could not put reverse without it sounding, I put a smal lift in to the base of the transmission were the mount is, to push it up (for testing purposes) and the grinding stopped when moving shift to reverse, Now I know I need to order the mounts. anyway just an idea.

veedubbed

My 5th gear grinds, I just rev match it. I hardly ever use the clutch to shift anyway, so it's no big deal.

Acesanugal

iTrader: (5)

Rev-matching only ensures that the motor is spinning over at the speed to suit the gear you're going into.

It is the Synchronizers' job to speed up the gears themselves to the speed of the input shaft. If your Synchros are on their way out or do not exist at all, Double Clutching is required to take place.

If you are shifting without the clutch, you're still using the synchronizers..but you're actually placing a higher load on them, burning them out more quickly. The clutch engages and disengages for a reason.

SaabGuy

I performance shift my motorcycle sometimes without using the clutch but its much easier than with a car due to such close gear ratios. I cant wait for the rpms to drop fast enough on a car, but yes I've shifted without using the clutch on occasion and its fairly smooth sometimes.

Whatever I do 5th gear grinds. Double clutching or not! Short of the car not even moving it will grind super easy no matter how gentle I engage.

Maybe I should just powershift the hell outa this tranny until its busted... NAAAA

Bronze MFP

whats the hurry that you can't wait for the revs to drop to engage 5th smoothly?
the rotary gains and drops revs pretty quickly for an engine, i don't see the problem

SaabGuy

Cause I live my life a quarter mile at a time...

No really, I cant get it to engage smoothly no matter what. Believe me I've tried but all I've found were rocks in her belly.

Acesanugal

iTrader: (5)

Well...then do the extreme.

On the upshift into fifth from fourth, put it into neutral and let the clutch out. Use the throttle to bring the revs to EXACTLY where you need them to be for the speed you're going, and then put it into gear.

It'll be more like catching the revs, honestly...with the throttle.

Are your mounts okay? Shifter bushings?

veedubbed

Leaving the clutch engaged, pulling out of gear, letting the revs drop, then pulling into the next gear is keeping the gear speeds sync'd with the engine speed. As long as you know where to pull it into the next gear, you are doing the job of the syncros.

zbrown

I am perty sure Aaron insinuated this with his first post.....

double-clutching involves rev matching both ways,..... You say you rev match when you are down shifting while double-clutching yes, but essentially you are rev matching just the same while double-clutching and up-shifting. You are just allowing the falling revs to do the matching for you. It just requires less input than down shifting

If you have ever driven a truck it is obvious, it is just a faster process in the 7 transmission because the syncros allow for error while matching, and the fast reving, unreving nature of the small engine

I am talking double clutching, not just rev matching

zbrown

If you were double clutching properly it would still shift seemlessly..... unless you messed up some splines

SaabGuy

I doubt that since its been a failing gear for sooo long.

I've been around a bit and know how to double clutch. Shoot I've been driving manuals agressivly for about 10 years counting and even replaceed a few clutches myself. 5th gear just sux with this tranny; it makes the car sound like a piece of crap everytime I shift into 5th but Im still truckin!

YA OK if I rev match OR double clutch it the shift gets better but its still a pos going into numero cinco.

Acesanugal

iTrader: (5)

What the hell was the point of this post..? Aaron suggested rev matching, not double clutching. Rev matching alone would not solve anything because it still requires a synchronizer. But hey, even though it will still grind, he'll be at the right engine revs for that gear! w00t!
Geez...