I've got a 38 1/2 ton with a 36 motor, 3 spd on the flr. Can a 4 spd be swapped or does it involve changing the rear end too? Tks~JH

 

A 4 sp from the same era will bolt right up.You hav an enclosed driveline so you need a 4 sp set up for one.Not sure if driveline and torquetube need to be altered.Also,trucks with 4 sp trans usually had an 11 inch clutch.Not sure if you can run the truck 4 sp with the car clutch.I have all the stuff you need....incl rebuilt trans never installed,proper flywheel for 11" clutch. Shipping could be high. GB

 

Henry, I dont know what your objectives are with the proposed switch. If you are looking to change the tranny to the same era 4 speed, then you will end up with a first gear pretty much unusable except in stump pulling conditions. If you use it in regular driving, you shift from first to second at about 5 mph.
If your idea of a 4 speed is more modern, then there is a whole lot more involved.

 

I just thot that another gear would let the engine run at less rpm's and still cruise at 55-60, rather than working so hard to do 50!! Sounds like it'd be more involved than a straight tranny switch. Tks for the inputs!!! ~JH

 

The 4 spd still had a final drive ratio of 1:1, just like the 3 spd. Like 46yblock said, a 4 spd switch would provide no improvment in driveability. The 1 st gear on th 4 spd was only used for heavy lugging...in fact in the '46 owner's manual it says to skip first gear unless lugging a heavy load. Only way to lower your RPM's is to put in an overdrive trans, which starts to get more complicated and more money (adaptors, swithc to open drive, etc.)

 

Thanks guys, that's what I wanted to know. May as well leave it the way it is and save alot of trouble and expense!!

 

No such critter as a 3-speed + overdrive transmission that is a bolt-in for your stock 38 Ford pu. What Ford used back then were 2-speed rearends with overdrive,called "Columbia rears". I have a complete one for sale with all of the controls that is still in a 40 Ford Standard 2dr sedan if you are interested.
It will bolt righ into your chassis and all you will have to change are the backing plates and the drums because the 40 brakes are hydraulic with 5 inch bolt patterns.OR,you could just keep them and convert your 38 over to hydraulic brakes. I am in northeasten NC if you are interested.

I also have a 38-39 Ford pu cab for sale that is chopped. Cab and doors only. PM mail or email me if interested in any of this stuff. Getting sick and getting old,and damn near everything I have will be going soon.

 

to keep it closer to original i knew a few model a restorers they used a three speed and overdrive out of a early fifties merc or ford but you have to have a bellhousing adapter made and modify the the drive shaft tube and shaft last one i seen was a 33 it toped out at 65 on the 4 cylinder

 

On the subject of the 4 speed, and the 11 inch Clutch & Flywheel. My 37 has the 4 speed which will be disappearing, as in not returning to its cradle, at least not in my truck.

To further the stump puller it has a 4.27 ratio, which also will be changed to some thing a little more user friendly like a 3.78 ratio. Last but not least it does have a 9 inch Clutch and Flywheel. Now I know that the engine was rebuilt and maybe the 9 inch was an after thought, but its there.