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Discussion Starter · #1 · (Edited)
I currently have an AW4/np242 in my 89 heep. I like this transmission tcase combo and would like to retain it in it's factory location to keep from having to modify my driveshafts and crossmember.

Does any body sell adapters for this transmission? What modifications would have to be done to the tconverter to make it work with the 4bt?

If this is not a feasible option what is to be said for the th400 usually found behind these motors? Will it provide the gearing for 25+ miles to the gallon @ 70 mph?

Maybe I'm hoping for to much, but I was always told it was better to shoot for the moon and miss it than to aim for a cow pie and hit it. :dustin:

Thanx for any suggestions.

Tyork_tex
 

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I've seen at least one place that doesn't recommend putting the AW4 up against a GM V6, never mind a V8. On that basis, I'd be hesitant to put it on the back of a 4BT.

Also, it's a fully computer controlled trans. I don't know if there are aftermarket controllers or work-arounds for it, but that's going to make it a bit more entertaining, as well.

As for the TH400 getting 25MPG, it's only one part of the equation. The rest are your differential ratios and your tires. You can use the calculator at http://www.4lo.com/calc/gearratio.htm to figure out where you'll be with what combination. From what everyone says, sweet spot to run is around 1700 RPM at whatever cruise MPH. It's going to be much easier with an overdrive transmission and lockup torque converter, though. Have you considered the 700R4? Several folks here have used them w/ 4BT with good results.
 

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Discussion Starter · #3 ·
No I hadn't. I assume that is a gm transmission as well. What all were they offered in?
 

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Yep.. GM from around 82 up until the 90's - 92 IIRC. Then it switched to the 4L60E. Same transmission, basically, but computer controlled.

Used on a LOT of GM stuff, cars and trucks. I've got one in my 90 C2500 behind a 350. It didn't see a trans fluid change for 100K when my dad had it, has 220K on it now, still doin' fine.

It does have some "gotchas", though.

You want a later model one, as the early ones had some problems with pumps and internal parts. 87 and up should be OK.

Also, it's NOT a heavy duty trans by any account. You DO NOT tow in overdrive, at least that's what everyone says. Dad towed in OD all the time with the one I have, and that was dragging a 30' camper loaded with everything the stepmother needed to survive 30 days of being gone from the house (READ: Was lucky to close the door on the camper when she finished packing..) Didn't seem to do it any harm..
 

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Discussion Starter · #5 ·
My aw4 has a power/comfort toggle switch on the dash that, from what I have been told in power mode,ups the trans line pressure, modifies the shift points, and locks the tc. Is it possible to duplicate this with the th400, the 700r4, or the 4L60E?

Thanx.
 

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where did you read that you can't put it behind a GM V6? It would depend on what GM V6 for starters, cherokees came with a 2.8L GM V6 gutless wonder, it could certainly hold up to that. The AW4 came behind the 4.0, loads more powerfull than the GM V6. The AW4 has been known to hold up behind PLENTY of power. There are people with stroked 4.6/4.7L jeep 4.0's running around with stock AW4's reliably. The AW4 also came in Supras. There are guys with TT supra's running AW4's, so i would definitely say that it can handle power. This is not to say it can handle the massive low rpm torque of the 4bt, but i would bet that it would stand a decent chance in a DD.

There is aftermarket controller support for the AW4, but i do not know how complex you can get. You can get it to control shift points, paddle shift even, but i'm not sure what else. They all have a stand alone TCU, so it does seem feasible.

the TH400 and 700r4 are not electronic, so switches will only control the converter lockup if it has it, everything else is a mechanical linkage. the 4l60E and 4l80E are totally controllable with aftermarket computers like the compushift unit that i plan to run.

Personally if you can figure out adapters to get it mate up and they aren't to expensive, I would give it a shot.
 

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Discussion Starter · #8 ·
I guess I could always run it till it quits and look into trading the th400 for a 700r4 in the meantime. That all really depends on how much it would cost to mate the AW4 up to the 4bt.
 
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