The Stovebolt Site Forums The Shop Area Engine Shop benefits of later model 3 speed guts

Other than the quieter helical cut first gear, would there be any benefit to upgrading the internal parts of a 1938 truck 3-speed transmission with parts from a later gearbox? Too bad first gear was never syncronized.

Rob

A good question and it can be done.
I updated the three speed I had in my 37 truck with 54 transmission guts. Everything worked fine and it did make for a better transmission. I soon tired, however, of not being able to move well in traffic, always having to down shift to second and having to come to a complete stop to shift into first gear.
The real deal is to find a mid to late 80's T-5 five speed transmission commonly found in the S-10 Blazer. With an adapter from Buffalo Enterprises and an open drive line, you can have a syncronized first gear, and overdrive gear to keep up with traffic, the other benefits of a T-5 transmission. You will have to convert to an "open drive" line, but it is not that hard to do and there are quite a few different rear ends that will bolt under your truck from a 55 Chevy (Powerglide) car to an S-10 rear axle.
My truck has a 55 Chevrolet car Powerglide rear axle, a 3.54:1 gear, and a 1985-1986 T-5 transmission along with 54 Chevrolet car front spindles, hubs and brakes and it is a joy. I can put virtually an wheel I want on the truck and I'm not restricted to a 6 lug wheel, I have Bendix brakes on all four wheels, it stops on a dime and I can cruise at 70 mph all day long with a tach reading of 2200 RPM's.
I think you're thinking right!

I have considered doing the T5 conversion, but for now I'm concentrating on trying to build my truck in the late 50's drag race/dry lakes push truck style. So I'm trying not to use any parts newer than the late 50's or early 60's.

So, are there actually any other benefits to be had from any later internal parts other than the quieter first gear? That doesn't really seem to be enough reason to go to all of the trouble of rebuilding my existing gearbox. It only has 37,000 miles on it and I kind of like the whine in first.

Probably some wear, which can cause a whine.
The other thing that can happen with closed drive lines is that the seal at the top of the torque tube behind the transmission can go bad and the oil from the transmission can leak down the tube to the rear axle housing. The transmission is then dry and the brass clutches in the transmission start to breakdown. You'll know this when you see small brass particles in the bottom of the transmission when you drain it. This, of course, can be stopped with an open drive line and leads me to the reason I dumped the torque tube concept. I rebuilt my stock transmission, as stated, and after I reinstalled it, I was constantly checking to be sure the oil form the transmission wasn't draining down the torque tube to the rear axle. It became an obsession and my greatest fear was that I would be on a road trip and loose the whole transmission-real axle in the truck due to it "burning up".
On your other post, you mention trying to keep the truck a "period correct" push truck.....I think you can do that easily with an open drive line a T-5 transmission. Take a look at my pictures and you'll see very little that would give you a clue that my truck isn't a basic stock truck.