Trans swap question

[oldmopar]

Will a 4 speed from a 1-1/2 - 2 ton be a direct swap into a 1 ton both are 1st series. I think there maybe be a different but not sure.

[Dodgeb4ya]

Nope. The input shaft is a 1-1/4" or 1-1/2" X 10 spline count. The light duty up to 1 ton trucks use a 1" X 10 spline input except for fluid drive trucks. Also the brake drum U-joint flange is bigger on the heavier trucks.

[oldmopar]

Thanks I thought there was a difference.

[austinsailor]

Along the same line, I have a 1/2 ton with a 4 speed and the bigger clutch. As shown in another post, it was torched out.

I have a 3/4 ton parts truck with a 3 speed (yes, I know that seems backwards!) and I have hopes of pulling the clutch and pressure plate from the 3 speed 3/4 ton and using it on the 4 speed 1/2 ton. Am I going to be disappointed?

[greg g]

The differece is in low gear. The truck 4 speed has a granny gear usefull oly if you need to pull your house of its foundation. These are super low gears with a top speed of about 8 MPH and are rarely used. Normally the other three gears ratios are the sam between the trasmissions, so the second in the 4 speed is equal to 1st in the three speed then 3rd equals 2nd, and 4th equals 3rd, with both having a 1 to 1 top ratio.

So if you are not going to be using your truck for heavy duty hauling or towing, you should be fine if everything mates up.

[austinsailor]

I was mainly wondering if the clutch from the 3 speed would fit the spline of the 4 speed. I'm sure the pressure plate will bolt up. I plan to keep the 4 speed if I can clean the shaft up well enough.

[Dodgeb4ya]

1/2 to 1 ton 4 speed input shaft splines are all the same 1" X 10 spline, same as the 3 speeds. 4 spd and 3 spd case mounting bolt holes are different though.

Edited December 15, 2009 by Dodgeb4ya