VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Transmission swap

I have a '37 1/2 ton pu with a 3 speed tranny. It is low geared. Is there a direct swap I could make to get a little higher gearing? Maybe a car trans?
Thank you
honk1e
VCCA# 50704

All 1937 and up 3 speds are geared the same. 2.94 ratio in low and 1.68 in 2nd. That goes right up to 1965 6 Cyl. and 1957 8 Cyl.car or truck.

If you're referring to highway speed you need to look at the rear end gearing, not the transmission. The Master car had 3.73 gears. How easy it is to swap them into a pickup housing I have no clue.

45 MPH is going to be the maximum speed for comfortable driving in a truck. The interior is very noisy in a truck due to lack of insulation and all hard surfaces in the cabin.
There was an optional 3.82 gear set made for 1/2 ton trucs whiich would slow the engine speed 7% or about 4 MPH at 45 MPH.

Changing to an overdrive gearbox (which involves a lot of other modifications) or changing rear axle ratios are about the only 2 options available for highway speed change. This will reduce the load hauling and hill climbing ability though.
Tony

As the others pointed out in, albeit roundabout way, the transmission's 3rd gear is drive or, in other words, straight through. The same would be true on any three-speed transmission unless it was coupled externally or internally with "over" drive.

Owing to it being a 37, I would encourage you to get a later model pickup that will allow the 3:55 or 3:74(?) differential gearing or modify the 37 to accept such a differential.

I agree with Gene that those old pickup weren't intended for relatively high speed.

Good luck with it.

Charlie

Note: In my opinion pickups didn't start both driving and riding well until Chevrolet came out with ones with the coil springs - instead of leaf springs - in the rear. About 68 or so, as best I recall.

See if this previous thread helps. The person referenced as Ray W did the 355 swap into his 1936? but i could not find the thread. He is not currently active on the site and was a victim of Calif. wild fires . Try searching for the following thread. .
#401254 January 06, 2018 12:16 Perhaps someone with more expertise than me can find it and post a link.
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The modifications that Ray did are way, way, way,way, beyond what 99 percent of the folks on this site are capable of doing.

I must take exception about trucks not being driver friendly until they had coil springs. I enjoy driving my 51 1Ton Canadian GMC, which is mechanically a Chev, on many roads including highways at 60 mph. Now I do have a rested gear set of a 4:10 ratio.

I AGREE, the Advanced Design trucks can be driven comforably at 60 MPH.

Ray W (I think he used the forum name “Brino”) is very talented and had the equipment to do the job correctly. I hope he is recovering from their loss due to the wild fires.

His technique included making a “hybrid” driveshaft that was the correct length and had the correct splines to adapt at each end.

I will be surprised if we hear from the original poster again.

I completely agree with Gene that just because you change the gearing the truck is not intended for driving at higher speeds.

Thanks for the info. I guess I will just allow a little more time to get where I am going.
honk1e

I agree with Gene concerning the noise in the cab these trucks make. I do not understand why they made a radio for use in these trucks. Mine is a '57.

FWIW my 38 will easily do 60MPH with the 3.73 gear. If a torque tube assembly out of a Master car is available that might be an option.

I agree with Tiny that a lower rear axle ratio helps with the engine speed.

On the other hand I’m not sure that would make the truck any more drivable at 60. The noise level in the cab is similar to rolling downhill in a metal trash can full of gravel.

Even more of an issue is the very stiff suspension with the single acting lever arm shocks. Unless you have some load in the truck it is a much rougher ride than similar year cars.

The 1/2 ton truck drive line and differntial is different from a car and follows the 1936 passenger car design to an extent.
60 MPH in a 1937 truclk feels lile 90 MPH in a car with any gearing.
If the 1937 truck has the original restrictor built into the carburetor to intake manifold insulator block 60 will be nearing the trucks maximum speed.

Note: This is longer than first intended so read at your own risk of being bored and wasting valuable time doing something more satisfying such as working on your old Chevrolet.

Old 216,

No need to take exception. The reason i stated "In my opinion" was to eliminate any notion by anyone that I was making a universally accepted factual statement. Just my "opinion." Nothing more. I seem to have failed in my attempt to convey my intent. My bad.

My father had a 54 (or could have been a first series 55) Chevrolet pickup that to me rode and drove little better than I remembered those of earlier years such as the 41-47 first series and 47 second series thru 53. I have had both 51 and 53 Chevrolet pickups. To me, neither rode or drove very well. Later he got a 68 Chevrolet pickup with the coil rear springs. It had enough wheel-base and unloaded or unloaded softness of ride that it was impressive to me. It had the cheaper interior, straight six cylinder engine and standard transmission. Bottom of the line so to speak. He once told me that after many miles, that he never had to add oil to the engine. Does Chevrolet make a great six cylinder engine or not?!

My father and I used the 68 to pull a heavily loaded trailer to Carlisle and Hershey back in the seventies. My father built the trailer out of two Model A or so truck chassis and it was really quite heavy with nothing in it. I had a heap of Chevrolet parts and they were predominately all heavy metal stuff. The 255 C.I (I assume that was the displacement but not sure) bogged down to about 25 mph in second gear for a few miles climbing the two hills in western Maryland on I-70 West going to I-81 North. Hagerstown, I think. Still, it kept tugging along and never missing a beat. Excellent truck and it road well and steered well. The seats weren't too comfortable but you only get what you pay for.

I believe my father, if asked, would have said that the 54 Chevrolet pickup had been his favorite truck. It was a top of the line, light green, with chrome grille and all, which made it right sharp looking. He got it while I was serving in Alaska back in 1954-56.

I apologize because this has been a bit off threads regarding the instant question posed by "honk!e" about a possible transmission swap for his 1937 Chevrolet pickup.

Hope everyone is doing well. I have just now come in after working on the brakes on the 41 coupe. Yes, still at it. Messed up the setting on the vacuum shift and have been looking for the tool to readjust it. No luck. Those things are hard for me keep where I can find them. One of our posters here on Chat gave me one and I lost it too. I think the instant one that I can't find is the third one I've had. Mercy!

Best,

Charlie

BTW: I hope to see as many of you regular posters as I can in BG. Please don't perform escape maneuvers if you see me coming around the corner. You know. I'm old but try to avoid long windedness. "Try" is the key word.