98 WS6 T/A Clutch/Transmission Problem

[Racr_X]

I posted about this problem a month ago and have been fighting this car for a solid month. Can't seem to fix the problem. From my original post.......... the problem:

When the car is cold, quick shifts on the 2-3 and 3-4(4-5 also) make a grinding noise when going into gear......... goes into gear every time. When bone cold, it even does it at any rpm, quick shifts only.

After driving the car for a little while and the car warms up and after using the clutch some too...... the grinding noise goes away and it shifts fine. I initially thought I had a synchro problem but since the noise goes away after using the clutch for a bit, I'm almost positive it's the slave or master cylinder issue.


Here's what I have done so far:

1st - Blead the clutch until all the original fluid was out, all new fluid. Still have problem, if anything it got worse.

2nd - Pulled the transmission and had a new slave cylinder installed, blead system again. Still have problem.

3rd - Drained the transmission and added new fluid. Still have the problem.

4th - Installed a new clutch master cylinder, blead system again. Still have the problem.


What do I do now? I'm totally stumped and this is getting expensive. My mechanic says its the synchros in the tranny but I still don't understand how they could get better after the car warms up.

[fastTa]

It sounds to me that it is not clutch related but definitely a collar/synchro mating problem. The difference in RPM between the dog teeth on the collar and the gear itself is the grinding noise you hear. Synchros are very picky about having proper friction to mesh correctly.

By you saying that the problem goes away after getting warm, that would strongly suggest that it is a synchro related issue.

I would strongly recommend a product called GM Synchromesh. You can get it at any GM dealership for $10 a quart. I would be willing to be that will solve your problem.

Another possibility could be that the inner hub of the synchro is not sliding properly within the outer hub. This is done by way of several springs with a ball bearing on one end. When this happens, it will not allow the dog teeth to properly enagage the gear.

I'm assuming you have fairly low miles consdidering it is a '98 so this last problem would be less likely than the first problem I mentioned I would think IMHO.