swapping Cherokee Sport 4x2 to 4x4 - possible?

[Rick Anderson]

True

Nope, the ECM doesn't controll the aw4, the TCM does, but the ECM expects some sort of signaling from teh TCM that's why the need for a specific ECM when TCM is is present.

You're not making sense here, read the above.

I agree, the AW4 has its own Trans Control Computer, so your making perfect sense, for the AW4. Which is the overwhelming majority of Auto Trans for Jeeps.

BUT, and I'm showing my bias here because I'm considering a swap from the AX-5 to a 30RH/A904 (I've got the 2.5L, '95 XJ), the 30RH is a purely hydrualic trans, except for the Torque Converter Lock-Up, which is controlled by the Engine Computer, ECM. It does not have its own computer just for the Torque Converter Lock-Up, so the ECM does this single additional function. I believe that is true for the 30RH, correct me if I'm wrong.

You make a very important point, because what I said is wrong for 95% of the Jeeps out there, its only the few that use a 30RH/A904 that I would have been correct. Thanks, cause even if I was right for the 30RH, I'd still be steering the overwhelming majority wrong on that point.

 

[TGFH]

So when I do my swap will I really have to replace the 5 speed I have? The thing is really tight and hardly driven at all.
Thanks

 

[Kejtar]

So when I do my swap will I really have to replace the 5 speed I have? The thing is really tight and hardly driven at all.
Thanks

the 2wd transmission will require some major work and parts if you want it to mate a tcase to it. It's simple and more practical to swap in a new transmission.

 

[Rick Anderson]

If you have a donor car to scrounge all the parts from (the only practical way to do this), AND your determined to keep your existing transmission.

I would imagine you could combine the parts amoungst the 2 transmissions to get what you desire. Thats a lot of work, I "THINK" the only difference is the output shaft (length and splines), you need to research that, because I would not be surprised if there was a difference in the case and the XFER Case does NOT bolt right up to the bolt pattern of the 2WD Extension Cone for the Slip Yoke. A new output shaft, plus maybe an adapter, can be very expensive, plus changing the output shaft requires stripping down the tranny to point, that your basically doing a rebuild.

Look for a donor with the same transmission, then you can strip down both and do a rebuild of the trans using all the best parts from the two, and use the couple necessary parts for a 4WD trans.

 

[Jeff in VA]

X2

You have to swap to a 4WD version of your tranny unless you want the serious hassle of rebuilding it with 4WD parts. But you can reuse the crossmember, tranny mount, clutch, and slave/throwout. You will need a longer speedometer cable most likely, unless you can stretch your 2WD one back to the TC.

I converted my 2.5/AX5 MJ to 4WD a couple years ago. PM me if you need help (and don't be swayed by those who say "just buy a 4WD 'cause it'll be cheaper ).

Jeff

edit: Rick slipped his post in while I was typing. The AX trannies are a 3 peice design, front, intermediate, and rear section. The rear section of a 2WD is a long extension housing encasing the longer end of the output shaft, that's splined differently than the 4WD output shaft. A 4WD rear section is bolted to the intermediate section same as the extension housing of a 2WD, but is shorter and flanged to mate to a transfer case, and the output shaft is correspondingly shorter.

 

[Rick Anderson]

edit: Rick slipped his post in while I was typing. The AX trannies are a 3 peice design, front, intermediate, and rear section. The rear section of a 2WD is a long extension housing encasing the longer end of the output shaft, that's splined differently than the 4WD output shaft. A 4WD rear section is bolted to the intermediate section same as the extension housing of a 2WD, but is shorter and flanged to mate to a transfer case, and the output shaft is correspondingly shorter.

Basically, to sum up what we both said; you'll need a 4WD donor vehicle with the trans you want. Its is far easier to use the 4WD trans than trying to change your existing 2WD trans to 4WD. To swap the couple of parts that are different will require a strip down and rebuild equalavelent to doing a rebuild of the trans.

IF, the donor 4WD trans is in poor shape, and the same kinda trans (AX-15 2WD and AX-15 4WD) and you think your capable of doing a total strip down and rebuild of that trans. Then you could strip down both, and create a 4WD version of the trans using the best parts from both trans. If you do it right, it should be as tight as your original 2WD trans.

Pretty sure the AX-15 is fully rebuildable, someone correct me if I'm wrong. Some of the late model New Venture transmissions are put together with crygonic interference fits and things like that, that makes it just about impossible to strip down the trans to the point of removing the gears and synchros from the shafts. At least my NV350 on my Neon R/T is like that, maybe the Jeep New Venture Trans can be fully stripped down, but I'd figured that out before I committed.

 

[lawsoncl]

I think you need to swap ECM when you swap tranny's from Manual to Automatic.

Most vehicles (Jeep as well as all the others) have Torque Converter Lock Up that is controlled by the ECM.

So, swapping in 4WD, ECM stays the same.

Swapping to an automatic from a manual, you need an Automatic Tranny ECM, to control the Torque Converter Lock-Up.

If the Torque Converter does NOT lock-up, tranny temps will soar and cook the tranny. As well, its a nice feature that improves mileage and cruising ability on the vehicle.

The Cherokees have an AW4 automatic which has a seperate Trans Controller Unit. If swapping to an auto from manual, you'll need to install and wire the TCU, preferably from the same ECU style (Renix, odb-I, or odb-II)

 

[lawsoncl]

True

Nope, the ECM doesn't controll the aw4, the TCM does, but the ECM expects some sort of signaling from teh TCM that's why the need for a specific ECM when TCM is is present.


You're not making sense here, read the above.

ODB-I and ODB-II have diagnostic connections to the TCU. The TCU also gets the throttle input signal from the ODB-I and ODB-II ECU. In the Renix setup, the TCU has it's own output from the TPS sensor and the diagnostic connection just goes to the yellow connector block on the passenger side of the engine bay.

 

[TGFH]

well you convienced me - I will look for a 4wd donor with a manual. I was only inside a tranny once - AIN'T goin' there again! (Late 60s VW days). Also mine is a 1995 Sport so is the newest model year I can get for a donor a 1996? Didn't they start changing things in '97?
Dean

 

[lawsoncl]

well you convienced me - I will look for a 4wd donor with a manual. I was only inside a tranny once - AIN'T goin' there again! (Late 60s VW days). Also mine is a 1995 Sport so is the newest model year I can get for a donor a 1996? Didn't they start changing things in '97?
Dean

You'll want an ODB-I donor, so 1991 HO engines up to 1996.

 

[TGFH]

okay - dumb "?" what does ODB-1 stand for

 

[Wiley Coyote]

okay - dumb "?" what does ODB-1 stand for

Actually it’s OBD and it stands for On Board Diagnostics. There are two different versions of the system. OBD I was the first and was used by most vehicle manufactures from the late ‘80s up till ’95 (Jeep XJs used OBD I from ’91-’95). The system works OK, but is not really standardized. Different vehicle manufactures used different style connectors and there was varying degrees of information. OBD II came on line in ’96 (ALL vehicles have it now) and has much more strict standards. All vehicles use the same diagnostic connector and are required to have the same basic information (some systems have more). There is a standard list of codes (i.e. P0135 is a generic O2 sensor malfunction) and some manufactures also put in their own specific codes. Both systems run fine, but if you have a problem OBD II is much easier to use. Generally it will tell you what part failed (bad O2 sensor) or at least tell you what is causing the problem (#6 cylinder misfire). That’s a brief run down.