transmission choices

[JJacobs]

I'm mulling over the transmission options for the next phase of the MJ.
1: rebuild the AW4 and cross fingers.
2: AMC TF727
3: AMC TH400.

I guess the 400 is stronger than the 727 stock for stock? I think the 400 will be OK with just a shift kit where the 727 would likely need some billet pieces here and there, and a bolt in sprag.
Then there's the AW4 can of worms. It worked OK, but barely, last year, at the end of the season it was pretty well smoked. But I don't have a clue about its former life or even the mileage. Hop-up parts or even a high stall converter are $$$$$

Last year was 480/540ish flywheel power/torque, shooting for much more this year. I haven't mucked around with trannies enough to know which way to go.

 

[streetpirate]

the chrysler 727 came behind motors pushing 550hp from the factory. for HD parts, good Mother Mopar will provide.

 

[jeepinwi]

around the midwest, an AW4 from the salvage yard can be had for as little as $60. They are basically a throw away part.

 

[MudDawg]

IMHO the TH400 is the better choice dollar for dollar...it has more parasitic losses than the other two, but is much cheaper and easier to build...I ran a 400 in a 4,200 lb Chevelle behind a healthy big-block with no breakage. the only real mod was a B&M sprag and a better center support bushing. Of course you need high quality clutches and steels and good bands...and use Type F fluid....better clutch pack grip than dexron.

 

[ren]

I would go for the 727, as you can buy a complete rebuild kit, minus convertor, for less than $150 from mailorder, rebuild it with SIMPLE hand tools, no stupid "GM J-tool -blah-blah-blah" garbage, and if it will live behind a blown 900+ horse hemi, then even the AMC should be not much trouble. AS for the T-400, good tranny, not so good 1st gear ( same with the 727, to be fair), cost over $400 for a GOOD kit, then you can go hunt down "improved" planetaries, "special" clucthes and steels, and so on. I would choose simple and cheap to rebuild, personally.
Oh, yeah... Don't use type "F" tranny fluid in a GM, those use Dexron-Mercon. Type"F" is for a "F"ord tranny. The chemical make-up of the fluids is not compatiable with the tranny intrernals when you go mixing and matching. you might get "better" clutch grip, but the "F" is going to end up causing trouble in the GM tranny.
The 727 uses Dexron, by the way.

 

[JJacobs]

I can't find an AMC 727 around here anywhere, but there's lots of 4WD AMC 400's. I've been told a car extension housing will bolt right up to the 400.

Other than availability the two sound pretty even- though the 400 has more of a power-sucker rep.

 

[MudDawg]

I built my FIRST TH400 in 1972...I used and have been using type F in TH400 trannies (I am not saying to use it in any other tranny against the advice of the manufacturer) for years with no problems at the advice of a trusted Tech Rep from a major HiPo aftermarket tranny parts manufacturer. The issue came up during a discussion about how to get some of their "tricky" fluid to use in the Chevelle. At that time I was told that their "tricky" fluid was type F with BLUE dye instead of red.

As a side note....I use type F in the A-904 in my Heep...it improved firmness of the shift.

 

[RaiderX7]

I had a chrysler TF 727 is my 86 Jeep J20 with a AMC 360. I pretty sure it only took ATF 3 for Chrysler tranny. Chrysler trannys take thier only kind of tranny fluid. I also use to work for a parts store and have been a Wrench turner for a long time.

 

[streetpirate]

wait, 904's came in jeeps right? thats a damn good light tranny. are the internals the same as the chrysler 904? will one bolt right up to a 4.0?

 

[JJacobs]

The 904 internals should be the same chrysler or amc. It'd bolt up to a 4.0 but you'd need to do something about the CPS. I think a 904 is a step backwards from an AW4, though.

 

[streetpirate]

has one less gear, no silly computer controls, and all the aftermarket you could want