Manual to auto th350 swap 2 wheel drive

[Gyva]

Is this swap as easy as taking out one and putting another, I read on another thread that the manual and autos are different lenghts. If thats the case than I'd have driveline length problems right? thanks for any info..


65 3/4 ton chevy is the truck.
Mike...

[61burb]

yeah you will have to have ur drive shaft shortend. you can shorten it your self if you have a die grinder and a welder. or you can take it to someone to have it done right. just my 2 cents matt

[gentry69]

im having my drive shaft shortened actually its done just got to go get it, but to get shortened and balanced and new u joints cost me 102 and some change i tried doin one my self but did it wrong and i had to get it redone i would just have some one do it if it were me but its possible

[1oldtruck]

I did this back in 1989 on my 63 1/2 ton LWB when I was younger and dumber. I don't know what differences there are between the 1/2 and 3/4 ton frames, but here's what I found for what it is worth. It was pretty straightforward but the most difficult part was removing the stock bellhousing X-member. I spent nearly an entire day under the truck with an air chisel removing the 8 rivets that hold it in place. Talk about tired arms! I used a short tailshaft TH350 and found that the rear transmission X-member from a Powerglide equipped truck worked perfectly. The mounting holes were already in the frame and I was still able to use all of the stock parking brake cables, etc. You will need to shorten your driveshaft a bit - not a big deal for a competent shop. Also, be sure to compare the spline count on the output shafts of both transmissions. I don't remember the numbers but they are different and you will need to change the driveshaft yoke to match. Be sure to have the new driveshaft balanced. The shop that did mine didn't balance it and it vibrated like crazy when decelerating through certain speeds. When you have it all back together, have the speedo re-calibrated. Good Luck!

[Gyva]

cross member and X-member same thing? If so the mounting holes on the old one won't line up with the new auto tranny? why else would you have switched this out 1oldtruck?



Mike...

[zenish]

the manual trans has its mounts on the bellhousing.the auto trans has its mounts at the rear.you will have to remove the manual crossmember.some people just cut it out.

[Gyva]

I gotcha... thanks for the info guys..



Mike...

[Gyva]

starter and a fly wheel too....



Mike...

[1oldtruck]

Yes, X-member is my shorthand for cross member. The explanation from zenish is correct. Wow, it's been awhile since I did this! I completely forgot about the flywheel. You will need to replace it with an automatic flex plate and matching starter. My apologies for not getting back to you sooner - just got back from the Grand National Roadster Show in Pomona!