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Old 05-04-2015, 12:35 AM   #1
mw67rs
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Convert TH350 from 2wd to 4wd?

I have a rebuilt TH350 for a 2wd and was planning to put it in my 4wd. I noticed the output shaft is longer on the 2wd. I did some searching on Youtube on how to disassemble a TH350. It looks like you need to remove all the guts for the transmission to get the output shaft out. Looks a little intimidating but not impossible. Anyone ever swapped a 2wd output shaft for a 4wd in a TH350.

I am fairly mechanical and have rebuilt engines but never a transmission. Is this something I should try or leave it to the professionals? I thought I could pull the only TH350 that was in the truck apart to get the output shaft out of it and if it looked like something I could put back together then give it a try on the rebuilt one. What do you all think?

Can anyone recommend any good videos or books if I do decide to give this a try?
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Old 05-04-2015, 02:27 AM   #2
andrewmp6
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Re: Convert TH350 from 2wd to 4wd?

If it was me i would let a trans shop do it and while they are at it rebuild it so its new and ready to roll.But any reason you want to keep the turbo 350 and not upgrade to a turbo 400 or run a 700r4 and get a overdrive gear?
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Old 05-04-2015, 04:22 AM   #3
donut
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Re: Convert TH350 from 2wd to 4wd?

When I needed a transmission for my K-20, they took a standard 2wd trans and made it for a 4wd. (I had a shop do it)

Output shaft has to be changed and the tailshaft lost. Your transfer case will bolt to where the tailshaft was. Entire trans has to be gutted, so rebuild it while you got it apart.

@andrewmp6, the output shaft is different between the 350 and 400. If you get beyond that, the driveshafts will have to be re-worked as the 350 and 400 are different lengths. When mine was done, I had a 4wd 400 in the shed. IMO, lot less work to get the 350 rebuilt.
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Old 05-04-2015, 09:22 AM   #4
jjzepplin
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Re: Convert TH350 from 2wd to 4wd?

Yup and you will need a different transfer case for the t400 as well.
I have a short t350 shaft for you.
I did my 700r4 and I used a video. Turned out fantastic and that was a long time ago.
I have this shaft left over from a build I was gonna do but went 2wd instead.
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