Speed Demon

iTrader: (14)

I see some others have grinding issues when the trans oil temp is cold.

My 4th gear synchro went out, so I rebuilt my T56 myself, installed the Tick stage II kit. Everything worked great for a few hundred miles. Now when trying to shift into 4th when the trans is not warmed up it grinds awful.

Once warmed up though it shifts ok into 4th, still seems more notchy than all the other gears.

Now I'm wondering why only 4th gear? Whey did only 4th synchro go out before. Did I assemble something wrong?

A little history. This trans and engine supposedly only has about 40k miles on it. I bought it out of a totaled Z28 and put it my M3. I was only able to go a few hundred miles once installed before the 4th synchro went out. Now as stated above it's grinding shifting into 4th when trans is cold.

BTW it's in the 30-40F here now.

thesource

iTrader: (60)

What fluid is in the transmission?

Speed Demon

iTrader: (14)

Dexron III ATF.

85MikeTPI

iTrader: (9)

What shimming values did you use on the input (and counter) shafts? Did you soak the new blocker rings in ATF before installing them? Did you break in the trans then change out the fluid?

Speed Demon

iTrader: (14)

I checked the shimming on the shafts and they where within spec by the book. I'd have to look up the values again.

I did soak the blocker rings in the ATF.

No, I haven't changed the fluid back out yet. I thought about that when posting this. I guess that would be a good idea. I've put less than 1k miles on it since rebuilding.

thesource

iTrader: (60)

I never soak the rings before installing them. I do use a light amount of high temp grease on them though to keep it from sticking before fluid can get up that high. As for allowing it to break in, while I usually encourage it, I have not seen failure from the lack of it. Shimming could be an issue but its strange that its only doing it when its cold.

How does the clutch feel when its acting up? Does it scratch going into gear or does it make a noise as you are letting off the clutch like its not going all the way into gear? Is the pilot bearing in good shape? Was the tip of the input shaft where the pilot bearing rides on in good shape?

Jonathan@Tick

iTrader: (5)

I've seen transmissions that were shimmed too tightly have 4th gear grinds or notchy when cold. Once the tranny warms up a bit everything loosens up a bit and it goes away IMO. With that said, a 4th gear grind in extremely cold weather isn't un common.

Speed Demon

iTrader: (14)

Good info. Guess I'll just keep driving it and skip 4th until it's warmed up.