Question on tranny swap 3-speed manual to C-6 automatic

[MustangSteve]

I am changing out the trans in my F-100 2wd, 1/2T SWB 70 truck from 3-speed manual to a C-6. The tranny I have has a slip yoke type fitting in back, like a car would have, not the bolt on shaft like I see in other pics. 1st question is: Do I have to get a different crossmember for the automatic? 2nd, is there any reason I can't use the slip yoke and have a shaft built for it? 3rd: Why do I do this to myself?????????

[FORDification]

A slip-yoke was used in 2WD short-wheelbase trucks with a one-piece driveshaft. Transmissions with a bolt-on yoke were used in LWB trucks and 4x4s, and had a two-piece driveshaft, and the slip was incorporated into the splines of the rear driveshaft section:






If the C6 has a slip yoke, you're golden. If it's got the bolt-on yoke, you're SOL...it won't work with your setup. Your truck's 3-spd SHOULD have a slip yoke driveshaft, though you'll have to shorten it to use with the C6.

The transmission crossmember is the same for all transmissions, manual or automatic.

[MustangSteve]

Thanks! Exatly what I needed. The tranny has a slip yoke. I either will get a used driveshaft or just have a new one custom made.

[Rick]

Delete Please

[craftsman]

and i think the output shaft on the c6 is bigger than the one on the 3speed, so you will need a slipyoke from a c6 trans.

[MustangSteve]

Thanks, I figured the slip yoke thing was coming as well.

[fordman]

i have a slip yoke shaft if you want it. i think it is either 67 1/4 or 69 1/4 from center of ujoint to center of u joint. i think it came out of a dentside