T56 3-4 synchro problems (long)

Hey guys, I was wondering if I could get your 'expert' opinion on this. :D :cool:

I have been having trouble with my tranny getting stuck in 4th gear. The first time it happened, I was in a 'friendly competition' with another guy on the street and slammed 4th gear and it stuck. I was able to get it out and drive it home, but I didn't use 3rd or 4th gear. Thinking I had bent the 3-4 shift fork, I ordered a steel one form D&D. I tore the tranny apart, and I found that all of the synchro keys had been sheared off. Nothing else looked bad, just the normal (not excessive) wear. So I replaced the keys, and installed the shift fork and put it back together. It worked great for about a month and had no troubles at all with it.

Then out of the blue while I was just cruizing along one day (MAYBE 1/4 throttle), as I pulled the shifter into 4th, the synchro ground a little. Then as I went to 5th, it got hung up a little in 4th, but not too bad. The next 2 times I went into 4th it did the same thing, only worse each time. Then the third time, it got stuck in 4th permanately.

I tore it apart last night and found the keys in the 3-4 synchro sheared off again. I am sure I am having an over-traveling problem with the slider, where it slides too far and the keys pop out and get sheared off. The problem is, I don't know what is causing it.

When I put it back together last time, I made sure I adjusted my shifter stops correctly. Actually, I turend the stops IN an extra 1/2 turn (as apposed to backing it out a 1/2 turn, like the directions say), and making sure I had complete engagement.

I called D&D and asked them what they thought, and they said it was most likely a shifter stop problem, like it wasn't adjusted correctly, but it was, like I stated before. They also told me that the shift forks do not bend, they almost always break.

Anyway, sorry for the long post, but I was just wanting to get someone else's thoughts on this. I have a PRO 5.0 shifter, do you think that it might be bent, causing this problem??

Thanks for any and all suggestions.

Hmmm I would like to see some pics

You can get ahold of me at night with twofast4lv@hotmail.com on MSN messanger or TwoFast4lv on Aim(AOL messanger)

Originally posted by OneFlyn95z28
Hmmm I would like to see some pics

You can get ahold of me at night with twofast4lv@hotmail.com on MSN messanger or TwoFast4lv on Aim(AOL messanger)

I'll see if I can get pics of it tonight, but I won't be able to post them until Sat. morning. What are you thinking? Do you have any ideas? Thanks for your help.

This same thing happened to me with my first tranny. Had it rebuilt four different times, and the same thing would just come back( sticking in fourth, and breaking keys). Even replaced thrid and fourth thinking that might solvle the problem, but never did. Ajusted the shifter just like you had. I bought another tranny, problem solved. Not what I wanted to do but, the people doing the tranny work couldn't figure it out.

I've had the exact same problems. I had an SLP shifter with no stop adjustment, so I bought a Hurst Billet plus, adjusted them like the directions said and still tore up the same stuff.

I thought I couldn't have been the only one having this problem!! My camera is broken at this time, but I will see if I can borrow the one from work on Monday and take some pictures. Hopefully I will have them by Tues. Anyone have any idea to what is causing this?? I really don't have the $$$ to go out and get a new tranny just to take care of this problem. Thanks for everybody's comments.

I've had it happen 3 times, the third is still ongoing. I've yet to have it fixed because its still driveable. The first time it broke off two of the three keys. The second time it broke off all three keys, got stuck in 4th. I said to myself, "I'm gonna get this mofo out of 4th." And I did. Only to have it not go into anything but 6th. I had to drive it home 29 miles in 6th, pulling away from stops and everything. Lots of fried clutch involved. A few stop signs and lights ignored aswell. I dont think I could have made it home with 3.42's, I'm glad I had 4.11's at the time

Sounds like you need to replace the detent plate and detent lever, as these parts provide the internal stops for the gates. At least inspect these parts for wear or damage when you've got the transmission apart.

Originally posted by Eric Bryant
Sounds like you need to replace the detent plate and detent lever, as these parts provide the internal stops for the gates. At least inspect these parts for wear or damage when you've got the transmission apart.

I will have to check these pieces out when I get home. I don't remember seeing any abnormal wear or breakage, but then again, I might have missed it.

Originally posted by Eric Bryant
Sounds like you need to replace the detent plate and detent lever, as these parts provide the internal stops for the gates. At least inspect these parts for wear or damage when you've got the transmission apart.

I checked out the detent plate and lever, it looks like there is enough wear to MAYBE cause the problem I am having. One question though, the wear looks uniform through all the gates. There are spots at each gate stop where it looks like the lever has slammed into the plate and chipped it off. They are relatively small, but I really don't know how much will make a difference. It is like this on all positions, except Reverse is not too bad, but 3rd actually has a bit more missing than the remaining 5 spots. The lever looks like it has the most wear, probably having about .010-.015" of wear on both sides. Could this cause the '4th gear only' over-travel? I just want to try to get it right this time so I don't have to do it again in another month. I am going to replace both the plate and the lever. I hope that this is the problem.

Has anyone else tried to replace these pieces and found out that not to be what was wrong?? It seems very logical to me. Thanks for the tip, Eric!

BTW, I re-checked everything in the tranny itself, everything looks fine (as far as wear), and nothing is broken (except for the 3-4 synchro keys). I guess I will put it back together with the new parts and hope for the best!! Thanks guys!!

when this happened like I said before, we replaced everything, and each time the same things failed.The only thing I could think of was that the tranny had taken, such a beating that if I didn't replace everything inside,or get a new one it was a waist of time and money.