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Discussion Starter #1
I have searched under many options and have not found the answer.
My question is, what would it take to convert the tailshaft of a 2wd th350 into a 4wd output. I've heard of removing the tailcone and (cutting?) the output shaft. I have also heard of having to gut out the tranny to install a shorter output shaft. I have this 84 XJ that has 200k miles on it and it needs a makeover. I have a 74 chevy 3/4 ton 2wd that runs GREAT except it is an eyesore. The truck has a rebuilt 350, rebuilt th350 with a B&M shift kit, and a rear 14 bolt with 4.10s and I would like to see this all in my jeep. I currently have full width D44s under it.
Thanx in advance.
 

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nice roach.
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Change the output chaft and extension housing.... the 4wd output shafts arent very expensive. I know because I just got a th350 rebuilt with a rev manul valvebody, hardened sprag, and 4wd output shaft. Good luck.

-j-rOd
 

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All you need is a new 4wd output shaft. You do not need a new tailcone. Try to find a transmission rebuild shop near you and see if they will swap you the 2wd output shaft and tail cone for a 4wd shaft. They may want a little extra $$ to do that because they got LOTS of 2wd shafts and not many 4wd versions.

To swap it out, it is actually fairly easy. All of the innards of the tranny come out from the pump side, so YES, you do need to pull everything out of the tranny to get to the shaft. Hit the library and find some information on rebuilding a TH350. It will explain how to take everything out and put it all back. Because you won't be touching the clutches, it is a fairly easy task. I did it to mine with basic hand tools.

Please...........for god's sake, DON'T cut the shaft and crap like that. What a BAD idea.

Good luck.
 

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I meant extension housing/ adapter to whatever t-case you are going to put behind it. If you need one I have one that bolts up to an np203.

l8r

-j-rOd
 

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why not cut the shaft ? been watching people do that for years with no problems seems like it would be easier to do than rebuild your tranny :rolleyes:
 

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alx said:
why not cut the shaft ? been watching people do that for years with no problems seems like it would be easier to do than rebuild your tranny :rolleyes:
Honestly I have never heard of cutting down a 2wd output shaft to make it 4wd. All I got to say is that I wouldnt do it on mine. Good luck if you decide to try it.:p
 

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seems like to cut the shaft properly and cut splines in it you would need to take it out of the tranny anyway. also a 203 bolts to where the tailshaft would bolt, except there is an adapter/mounting plate that goes in between.
 

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no need to respline the splines are long enough the shaft is just 1 inch to long or there abouts hell ive seen people cut them with a hack saw then mount up the adapter and case :eek:
im not saying its right just that it has been done and works :D
 

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hmm maybe ill have to try that some day.
 

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You can cut down the 400 short shaft 3/4" to mate it to a 4wd adapter plate, but I've never heard of this for a 350. Even the shortest shaft 2wd is abouth 4" to long, and I know the splines don't run that long. The shaft can be changed in an hour if you know what your doing, and the tranny is out of the truck of course. If you can get a rebuild manual for a 350, you can do it with normal tools. A couple of specialty tools make the process a little quicker, but it can be done without them. As said before your not getting into the clutch packs, so it's pertty much, disassemble, change the shaft, reassemble, easy.
 

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Discussion Starter #11
Thanx for the input. I have been looking at some tranny manuals and starting to get familiar with the th350 auto, but it's still not as good as hands on experience. I never thought that the splines weren't cut the full length of the shaft. Learned something there.
Thank you for al your input.
Robert E.
 

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Here's my cut TH350 shaft:


It was in a TH350 and mated to an NP205 when I got it. Trans case was cracked, so I tore the biatch down and kept the shaft. It looks like it was cut with a sawzall and touched up with a grinder. I know I could do a better job :D
 

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alx said:
why not cut the shaft ? been watching people do that for years with no problems seems like it would be easier to do than rebuild your tranny :rolleyes:
Yeah...........your right............pull out your hacksaw, cut that sucker and run it. :rolleyes:

I'm sure people probably have done this and it probably has turned out fine. But then I have heard of people going over the falls of Niagra in a barrel and living to tell about it. I'm not standing in line to do THAT either.

Why are people so scared of pulling apart an auto tranny? Your not going to REBUILD it. Just pull the innards out, swap out the shaft, put the innards back in. Not hard and requires NO special tools or knowhow.
 

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Supergper said:
I'll get a pic of my output shaft...my splines stop about 4" from the end...
There's three different lengths of 2wd TH350 output shafts. Commonly referred to as 6", 9", and 12" based on the length of the tailhousing. Spline length may vary - I don't know which length my cut shaft started out as :rolleyes:
 

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u2slow said:


There's three different lengths of 2wd TH350 output shafts. Commonly referred to as 6", 9", and 12" based on the length of the tailhousing. Spline length may vary - I don't know which length my cut shaft started out as :rolleyes:
I am aware of this and I have a 6" right now and I had a 9" shaft before and it was the same as the one I have now...I doubt the 12" has splines all the way...I am not saying yours isn;t a cut shaft I'm just stating mine doesn;t have splines all the way so there must be different style of 6", 9", 12" shafts :rolleyes:
 

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Discussion Starter #17
u2slow said:


There's three different lengths of 2wd TH350 output shafts. Commonly referred to as 6", 9", and 12" based on the length of the tailhousing. Spline length may vary - I don't know which length my cut shaft started out as :rolleyes:
After reading more of this I have discovered that the core tranny I disassembled just for the heck of it had the 6" shaft. I just crawled under my C20 with a tape and flashlight and realized that it measured 9", but now I may have to dig through the trash can and find the 6" shaft, it may have the full length splines. I rather would just replace it with a 4wd version, rather than just trying to save a few bucks, but if your cut down shafts are working fine (depending on length) then I might go that route.
 

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I Build transmission for a living and you can change shaft but a 2wd case is held buy the trans and a 4wd case is held buy the transfer case if you use a 2wd case you will rip the bell housing from the pump so stick with a 4wd K case it is thicker for a reason
 
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