Transmission guru's please step in

[tpiini]

TR-3550

My transmission upshifts fine, but I'm having difficulty downshifting without RPM matching. I asked about this here a few months back and the consensus was that even though I could upshift fine, my synchro's were bad. So one of my winter projects is the transmission.

I tear into it today and can find nothing obviously wrong with the exception of the teeth on my fifth-gear synchro ring being slightly worn. All the other rings look just like the brand new ones.

The one thing I DID notice was that it looked like the last person to fill it used regular motor oil, or something with the same color and consistency. I was expecting to find something more like ATF in it.

The Tremec book that I bought recommends a G.M. Synchro Lube, PN 12345349, with an alternative being Dextron III.

So any new thoughts? Does anyone know if the Synchro Lube is similar in consistency to ATF? Could the thicker oil have been my problem?

HELP???

[niles]

My first check would be to increase the throw of our clutch. I have notice that anytime any dragging occurs; ie putting into reverse cold at startup, or stiff shifting its caused by not completely releasing and causing sychros etc to do more work/effort to match velocities
gn

[HighPlainsDrifter]

Hi,
Your right the trans needs ATF dexron III, get the synthetic fluid it helps alot and keeps the trans fluid from breaking down when hot, yes it gets hot!
The clutch is probably dragging like Niles said, you need to make sure it fully dissengages or bad things happen like bending shift forks and having 2nd gear not dissengage while 3rd is trying to engage. This is the major cause of these internal shifted trans failures. Check the shift forks if they are bent, replace them.
Good Luck,
perry.

[RICK LAKE]

tpiini Was your bellhousing centered on your motor? If not you will wearout your pilot bearing or bushing and have a shifting problem. Is the clutch releasing? measure the airgap between the pressure plate and the disc or flywheel. The disc may be worn out. I had a centerforce clutch with this problem at high rpm shifting, removed the wieghts on the pressure plate and have had no problem since that. Was the fluid burnt in the trans? Any metal shavings or chips on the bottom of the case? Dex III is good for normal driving but when worked hard it breaks down. Clean out fluid good and put a systhetic fluid in there, like Royal purple or Amsoil. Where does your clutch pedal release at? Top or bottom? You may has just worn out the clutch. If you have complete clutch travel at the fork the clutch is shot. If a hydro throwout bearing may sure there is no air in the bearing, bleed the system. Same thing check the air gap when the pedal is pressed in. Let us know what you find. Good Luck Rick Lake

[tpiini]

Thanks for all the input so far. The clutch is fairly new according to the P.O. When I took it out it still looked new. The adjustment, however, was such that the TO bearing was constantly under pressure. Seemingly, having an opposite effect of the problem I've been encountering. The release point is about half-pedal, and I expect that will change to about 2/3 pedal when I set the thing correctly. I really don't think my clutch has been the problem, but I'll definitely check the gap when I reassemble it.

I'm thinking that the fluid that was in it was probably my main problem. Really thick stuff when compared to ATF.

Thanks more, Tom