The Stovebolt Site Forums The Shop Area Engine Shop 3 Speed vs. 4 Speed Tranny

I have a 1938, 1/2 ton with the stock 216 and 3 speed transmission. Needless to say, a top speed of 45 mph just doesn't cut it. I see discussions about a modified ring and pinion for the rear end, but it appears, that'll only get me 5-7 mph, yes?

If my research is correct, in 1939 they started using a 4 speed. In fact, I've noticed that most of the 1 ton and larger trucks ALL use a 4 speed.

Other than not being original, would there be any problems with me bolting a 4 speed onto my 216? Will it solve my "top end" problem? Can a guy that had never changed his own oil until acquiring the aforementioned vehicle handle the wrench work????

Thanks in advance for any and all input!

Jesse

It won't change anything top end. The top gear in both of the trannies are a 1:1 ratio. You would need an overdrive transmission to change anything on the top end.
Scott

he's right, the only thing you gain with the four speed is the granny low, great if you want to pull down a house, but not very useful for going faster.



-Mike R

If you have very small diameter tires, you can gain a lot by putting on large diameter rear tires. You can calculate it by doing a proportion using the tire circumferences. If you get a 10% larger tire, you can go 10% faster at the same rpm. - Scott

Yeah, I've gone to a larger tire which got me up to a whopping 45 mph!

Can anyone tell me where to look for a different ring and pinion? I tried Randy's Ring and Pinion, supposedly the "experts". All they could give me was the weather report for Seattle :rolleyes:

Any help is appreciated.

Thanks in advance, Jesse

Try Patricks on the links page. He's supposed to be pretty god with the older trucks.

If your truck has 30 inch tall rear tires, the 4.11 rear gear will give about 2750 RPM at 60 mph.The governed speed on 216's in bigger trucks was 2800-3200 rpm depending on the application.So if your 216 is in good shape,spinning it to 55 mph for like say an hour shoulbe be within design limits.
Some will say the engine won't last,I used to drive a 51 Chevy dump with a 216 wide open against the governor for a few hours at a time, day after day.Oh, it got to knockin after a time, but took about 4 months of torture to ruin the bearings.
Try it and see what happens,if she blows,I don't know nuthin