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TH350 or TH400


CanaMark
10-14-2005, 01:14 PM
Does anybody know the difference between the GM TH350 and the GM TH400. Which one is better. And what trucks and years are the Th350 found in. Is having a 3 speed auto bad for highway driving. I have always been used to a 4 or 5 speed manual trans and auto trans. But I see in mags alot of people use these 3 speed auto's. The main reason I am asking is I got a Ford 9" rear from a '81 F150 and a D44 front from same truck. I believe it has the C4 ford auto trans, with a borg warner 1345 Transfer case. I guess my next question is, are these ford auto trans c4 and c6 any good, and is the Borg Warner 1345 any good, are the c4/c6's comparable to the Th350 and 400. My ideal situation would be to have TH350 auto 3 speed hooked up to a NP208 connected to the Ford 9" rear with a detroit locker. Which detroit locker is best? I see like 2 different models of detroit lockers on the market. TrueTrac I believe is one. The D44 front from the ford wont do me any good. Any info you got about compatability issues would be appreciated.
The ford has a 302 5L V8, but I just want the 9" rear that I will put in my '93 Jeep YJ 4L 5 speed.

Ray H
10-14-2005, 03:19 PM
Very little in your post has to do with Jeeps. You may be better off asking about the TH350/TH400 on a Chevy board and about the Ford engine/tranny/tcase/rearend stuff on a Ford board.
As far as a 3 speed auto goes. It wont have an overdrive. if you have the correct differential gearing it will be fine for the highway. You may not get as good of gas mileage as you would with an OD tranny and you wont be able to go as low with the gears for off roading but it will work.
Back to the TH350 vs TH400.
The TH350 is a GM medium duty tranny. Its been put in many, many applications and has a good aftermarket for parts and adaptors. The TH400 is a heavy duty tranny and has been used mostly for 3/4 and 1 ton ton trucks and some muscle cars. AMC/Jeep did use these trannies a few years for there heavier vehicles. You should be able to get an adaptor to hook the TH350 to just about any engine, tcase combo.
Fords C4 is a medium duty tranny and the C6 is a heavy duty tranny. They were used for roughly the same type of applications as GMs 350 and 400.
The Ford 9" has alot of aftermarket support also. There are several different differentials available for it but there are also a couple different models of 9" with different spline counts, Im not sure what years came with what spline count though. Just an FYI, the TruTrac by TracTech isnt a locker, its a limited slip and is different than a Detroit Locker, which is a full case locker. Which one is best depends on how you plan to use it. The Detroit is much better for rockcrawling but you mentioned something about "highway" use so Im not sure its the best third member for you.

CanaMark
10-14-2005, 08:50 PM
Its for my jeep, coming off a ford. Its hard to search the web for anything. But thanks anyway. I will try other forums.

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