VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1937 Transmission

Hi All!

Not real familiar with early synchro transmissions and I have a '37 3-speed floor-shift unit out of a Master.

My question is - if you try to go quick on the upshifts (1-2, and 2-3) it always grinds a bit. . .but - if I slow down the shift significantly, or even double clutch it - I have no problems going up through the gears smoothly. . .

Is this the way these trannies typically act? Maybe there's a secret or some finesse to driving them?

Any help or advice would be greatly appreciated! Thanks! Brad

My 1940 3 on the tree acts pretty much the same as what you describe. Seem from previous posts, most say that these trannys need scyros and other stuff replaced and they definately are NOT canidates for fast shifting. Like mine, double clutching helps in some instances ........can be fixed tho,,,I`m letting mine drip a little and double clutching....I`m happy leaving it alone...very little grinding ,once you get the "feel" of it

This is not normal. With my '39 with a floor shift (same transmission) I could go from gear to gear as fast as you could shift.
Usually the syncronizers are weak. Years ago we would replace the syncro. drum and what ever else showed wear.
Believe it or not the same transmission was used up through 1965 with only minor changes. and on 6 and 8 Cyl. cars.
The years with the vacuum column shift were even harder on the syncros. because the vacuum asist pushed the gear change hard and faster.....even though you couldn't shift it as fast.

When I first went thru my car it was mentioned that a change of gear lube to 85w / 140 would help with the "timing" of the slide of the gears. Mine shifts very smooth. Thats not to say that mine might in better condition so it "works" smoother, but it would be an easy way to see if something as small as a gear oil change makes a difference.

I've never heard of shifting fast and double clutching happening together. Double clutching is typically done shifting big truck transmissions that don't have any synchro's in them.

I have never had grinding while shifting my 37 MD, but I don't shift it like I used to shift my old Pontiac when I was 16, either. I have noticed that if I put her in neutral at a stop light, she'll grind terribly trying to get into first unless I first stick it into second, which I assumed meant that the synchronizer was missing or worn out on first gear. It's not yet bothersome enough for me to pull it apart to check, but I would be curious if this is a common ailment.

Eli,

Many years ago my when my dad was teaching me the fine art of auto repair, he told me that if a trans had trouble reengaging first gear or reverse gear it usually meant that the clutch was starting to show signs of wear and was not fully disengaging to allow the imput shaft to go "neutral" and unload the gears / syncro's to allow the trans to shift without grinding.
The first gear in our '37's is a non-syncro gear, and requires the trans to be completely stopped before you can move the shift lever to the first gear position. If you have done that and it still won't go in, check your clutch adjustment.
Here is where a change of fluid will sometimes help that situation.

Exactly - double clutching and shifting fast don't go together. . .which is why I'm trying to get away from double clutching as a solution for a smooth shift.

Chev Nut - Any idea who is a good source for new synchros??

Thanks,
Brad

I got new synchro cones for my '41from filling station. That's where the wear was in my trans. It now shifts very smoothly.
Sid

F.S. number RW-453, $35.00 each
Actually the 1937-1939 syn. drum is the easiest one to find as a complete unit in NOS.