My dad has a 38 coupe with 8BA mated to a early toploader. While he was driving it something happened causing the rear wheels to lock up. I suspect this happened while he was downshifting but I dont know for sure. My brother was behind him and said he was slowing for a stoplight. Anyways when I got there it was locked up, I tried rocking it and getting the shifter into neutral to no avail nothing would move. If you started the engine and engaged the clutch it would kill the motor. We had it flatbed towed home and by the time it got home the shifter freed up and the car would move under its own power in reverse but if you shifted to any forward gear it would still kill the motor. I wasn't there when he took it apart (removed top) but he said there was nothing he could find wrong inside. I have the shift tower and another shift tower here with me now and I cant see anything wrong with the one that came off the car. So it must have somehow been locked into 2 gears at the same time but I cant see what caused it. and since it would eventually back up I'm assuming the 2-3 synchro was somehow hung up? He says the synchro slides freely and everything seems to be good now. So was this just some freak fluke incident or is there something we're missing? Any ideas? TIA
sounds like the rear-end might have locked up. if set up too tight or low on grease, will get hot and lockup after a few miles.
I think the definition of fluke is an occurrence that can't be explained, and probably won't happen again. If you can't see any damage, it probably can't be explained. Nothing out of place down on the syncro? Those boxes can't really have the two forks move at the wrong time unless the shifter detent is missing. Maybe check the shifter housing to see if the detent (or detents if it's a 39 style box) is in place.
Russco, don’t have any experience with your transmission, but we had a three speed truck at a shop I worked at years ago that if you didn’t shift it just right it would go into two gears at once and slide the rear tires. Did it quite a bit before we tore it down ,lucky the transmission didn’t explode. What we found was worn shifter parts,( in the transmission) this was a side loader, but they kinda work the same. They have a mechanizam that is supposed to not let you shift into the next gear before you get out of the previous gear. Slight wear on your shifter parts will circumvent this feature. Might check for that. Bones
Yeah John, thats what I said too. He said he did but he's 85 so who knows? I'm gonna try to get out there and look inside the case myself. The weird thing is though why the shifter wouldn't move at first. If it had a chunk caught up between the cluster and drive side I don't think that would hang up the forks? Maybe it would but it seems to me like it wouldnt. I've only been inside of one of these trans a couple times but they seem pretty simple. I'm stumped. The bad thing is he wants to put it back together NOW and I want to know why it did this first.
Yeah at first I thought this too but these only have 1 synchro 2-3 and a reverse slider. The way the shifter works I dont think its possible for it to move both forks at the same time. I donno? Thats why I thought maybe someone here has seen this before. If I had to bet I would think there is or was a piece of something that got caught up in it somehow and he missed it when he was looking. I'm going to give it a real close look see before we put it back together since I have the shifter tower assembly in my possession.
Might look close, the transmission we dealt with was a 67 Chevy 3speed. When we took the side plate off we saw a “ little” wear, but didn’t think we found the “ smoking gun”. We replaced all springs, detents seals,etc with new genuine Chevy parts. The problem when away. Bones
Look and see what shift tower you have.The early one would be marked 67A and the later with the much better interlock would be 81A. The early one can let the trans lock up,when two gears are engaged.
I went back and carefully reread your post. In the details you give the answer to your problem. “ when down shifting, rear wheels locked up... shifter wouldn’t move... transmission locked up “. Then after taking transmission apart, can find no problems. Classic symptoms of being in two gears at once. You have shifter problems. ( in my opinion) Bones
Shift tower is ‘36-‘38 style 68-7222 I do know the 39 tower has different detents that work from both sides of the shaft where the early only has cutouts on one side. But I always thought the improvement was in the synchronizer well if this is a somewhat known issue I feel better about putting it back together but I had not heard of the locking up issue. Just that the 39 was an improved design. I still can’t see how it did it unless it caught the front of the low/reverse fork somehow instead of engaging the slot like it’s supposed to.
Check for bent shift forks. Did it the one and only time I grabbed 4th gear in the traps. That was an expensive shift......
Check the lower end of the shifter lever.....the part below the half ball pivot. Kinda hard to see since you’re really just eyeballing it, but it should extend downward in a straight path, both when looking from the side and when looking front-to-rear. If it’s bent a little, it could be trying to shift both shift rails at the same time. Also, it should be the correct 36-39 type lever. The 32-35 levers would not work correctly. I doubt this is the problem for you.
I took the shift lever out of the tower and measured the 2 wear spots on it, the slot was pretty darn good and the lower ball area was about .015 -.020 short but i dont think thats bad enough to even bother to try to repair. and it is the correct passenger car lever for a '38. I doubt it. he's getting on in years but he knew his way around a cockpit at one time.
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