last call before AW4 rebuild

well the poor ol AW4 has been really struggling the last year or 2. The problem is extremely late hard clunky shifting from 1st to second. However if I start in "3" as opposed to drive it shifts much better. Faster and not nearly as clunky but still late. That is the only problem. Everything else is just dandy. I do know for a fact the previous owner replaced the transmission when there was 135k on the odometer. I'm at 170k now so its got 35k on it roughly. It was a factory rebuilt transmission. That's all the info I have. He killed the original transmission by overheating during sand play. So far the following actions have been taken. New tps sensor,done multiple flushes, new filter, always have ran a large cooler,kick down cable is adjusted correctly. Axle gears are new, transfer case is new. Drive shafts are new (Tom woods)
2000 jeep xj
4.6l stroker
4.10 gears
32's
242 t case
daily driver
from what I've been told by a local guy who builds engines and transmissions for racing applications he says the clutches are likely poor quality/ worn/ not setup properly to begin with. Sounds reasonable to me. I always hear people say aw4 transmissions are tough and reliable. Main reason I'm posting here is just to ensure that this isn't some stupid problem that could be an easy fix before I drop 2 grand on a new transmission. Any help is appreciated.

You've got D/M in there right? Not ATF+4?

Not sure if you can do this on a 97+, but it may be possible to drive it around without the fuse for the TCU in.

AW4's are tough as hell! I cycled mine in the trail rig past 280* multiple times last year and it still shifted.

You may just have a bad one. I would swap out another used unit and call it good. It takes about 3 hours to swap a AW4 out.

Also, like said, Dex/Mercon ONLY!

right. Dex merc. Only. Agreed had a buddy with a 90' xj he would beat to hell on with an old AW4 that came from a dudes yard in a trailer park. Well I suppose a used transmission would suffice. I just have the worlds worst luck with defective parts...

I'd swap in a used transmission before I'd drop $2000 on a new one. You can find a good AW4 from a wrecked XJ on craigslist for $150 or so.

I think I remember reading on a couple forums that people don't have the best luck with rebuilt AW4s. Its possible the transmission shop had no clue what they were doing. You certainly shouldn't have to replace a transmission with 35k on it, especially an AW4.

if I were to snag a used Aw4 IIRC it would have to be from a 2000-01 model right? Correct me if I'm wrong. 97-99 wouldn't work....cant remember if I read that somewhere

I'd try one last thing. Click on post 10 in the link below. Since it performs differently due to shifter position...........

http://www.cherokeeforum.com/f51/cruiser54s-mostly-renix-tips-153657/

Jolly_Red_Panda said:

if I were to snag a used Aw4 IIRC it would have to be from a 2000-01 model right? Correct me if I'm wrong. 97-99 wouldn't work....cant remember if I read that somewhere

Click to expand...

A 98+ should work. In 1998 an ISS (input speed sensor) was added.

http://www.naxja.org/forum/showthread.php?t=1053970

Before replacing an AW4 transmission with only around ~35K I would probably want some more diagnostics and opinions.

Thoroughly inspect and test wiring, connections, grounds, solenoids, TCM, PCM, linkage, etc. Later models XJs the PCM was added to the TCM along with other emission related programming.

Later model AW4s use a TRS (transmission range sensor) (NSS) ... I would inspect the TRS(NSS) plug for bent pins, corrosion, etc. Mixed and lack of signals can cause problems with the TCM and shifting.

as well as other plugs and wiring to the transmission and shifting solenoids.

A Jeep Cherokee (2000/2001) AW4 diagnostic procedures manual has some information regarding how the electronic functions operate and information how to troubleshoot them. Though most is written for use with a DRB-III tool, much of the diags & testing can be accomplished using a DMM, without a scan tool.

All the connections to the AW4 need to be ok,

A few notes:
The number one killer of the AW4 is incorrect/low fluids closely followed by over heating. Else wise, the box is reliable in the extreme.

If memory serves, with the '96 model year (OBDII) the TCM must be in circuit or MILs (CEL) will be tossed out for all to see. The PCM in the late models hold the shift parameters and the TCM executes the shifts.

With the TCM removed (late model), the transmission will lock into first gear when the gear selector is in the 1-2 position and will lock into third when in either the 3 or OD positions. Torque converter lock will not be available with the TCM removed either. Plus, of course, the MIL events...

As for durability, this transmission in a slightly different form sees 600Hp in modified Toyota Supras. The difference between that version and ours is an "extra" clutch in the 4th gear pack. A clutch that can be added in during the rebuilt of the transmission...

Year differences, beginning in '98 (again, if memory serves...) an additional speed sensor was added. In terms of being able to swap in another box, the OP will require a late model version or codes will be thrown and the TCM/PCM will, most likely, put the transmission into the "limp home" mode of operation.

Shift parameters. The neutral safety switch sends the gear selection status to the PCM. The PCM holds more than one set of shift points. Plus, for those that live at sea level and never see this, the PCM delays the up shift (higher engine speed) when the vehicle is "at altitude". Generally speaking, at altitudes above 3,000' the transmission begins to shift differently so as to compensate for the altitude induced reduction of engine power.

This may explain why the OP sees a difference in the shifting between the selector in the 1-2 vs 3 or OD positions.

Jolly_Red_Panda said:

well the poor ol AW4 has been really struggling the last year or 2. The problem is extremely late hard clunky shifting from 1st to second. However if I start in "3" as opposed to drive it shifts much better. Faster and not nearly as clunky but still late. That is the only problem. Everything else is just dandy. I do know for a fact the previous owner replaced the transmission when there was 135k on the odometer. I'm at 170k now so its got 35k on it roughly. It was a factory rebuilt transmission. That's all the info I have. He killed the original transmission by overheating during sand play. So far the following actions have been taken. New tps sensor,done multiple flushes, new filter, always have ran a large cooler,kick down cable is adjusted correctly. Axle gears are new, transfer case is new. Drive shafts are new (Tom woods)
2000 jeep xj
4.6l stroker
4.10 gears
32's
242 t case
daily driver
from what I've been told by a local guy who builds engines and transmissions for racing applications he says the clutches are likely poor quality/ worn/ not setup properly to begin with. Sounds reasonable to me. I always hear people say aw4 transmissions are tough and reliable. Main reason I'm posting here is just to ensure that this isn't some stupid problem that could be an easy fix before I drop 2 grand on a new transmission. Any help is appreciated.

Click to expand...

The solenoids control shifting. If the solenoids are working as expected, the wiring connections from the TCM/PCM and the ATF are ok. The transmission itself may be having some problems.

Not being a transmission expert with little experience with transmissions other than driving and maintenance. What I have learned so far about the AW4 and the XJ. The problem(s) described seem to be more likely an electrical mechanical problem rather than a transmission only problem. I would want to first rule out any electrical problems.

If you swap in a used or new/rebuilt AW4 any electrical problems (not inside the AW4) would still be present.

Having a newer AW4 connected to aged OE wiring, solenoid and transmission mechanical failure would be less likely suspect.

The TPS and brake lamp switch need to be working correctly.

__ TPS (effects shifting)
__ Brake Lamp Switch (out of adjustment can cause TCC problems.)

Some important components connected to the TCM are the PCM, ISS, OSS, TRS and JB (fuses).

There are other cables and connectors for the AW4, from memory there should be at least one 8-way connector (black) for the solenoids and ISS / OSS.

Other connections and grounds connected to the TCM.

Connectors: C107, C100,
Grounds: G101 (near starter)

There should be a write up someplace ...

(I have a few pics for the AW4 and TCM related connectors and some for the wiring but no way of uploading any of the pic information to the forum.)

I would start with a few simple things by inspecting and cleaning grounds and testing that wiring connections and power is ok.

While at the same time making mental notes how the solenoid shifting operates.

====

The TCC solenoid controls torque converter lockup
Solenoid 1 controls shifting 1-2 & 3-4 range
Solenoid 2 controls shifting 2-3 range.

While in 1st gear the TCC is disabled. When in 2nd, 3rd and 4th gears the TCC is enabled and activated based on various inputs such as rpms and other variables to determine when to lock the torque converter.

During normal acceleration sometime after each shift from 2nd - 4th gears you have torque converter lock. (the TCC solenoid becomes active)

Misc. If solenoid 2 is active or has an open circuit the TCC disables solenoid 1 and the TCC solenoid.

wsxjeep I recall seeing that thread before. thanks. good to know 98-01 is bolt in. I just cant imagine a transmission with 35k on it would have demolished clutches... the problem is specifically isolated on the first shift 1st - 2nd. acceleration from a dead stop is painful. its slamming hard as hell. if I start off light throttle and gently back off before it goes into 2nd it helps ease the clunk. I would think If there was severe mechanical wear wouldn't I have more problems outside of 1-2? I remember when we had the tranny pan off the valve body looked clean and new...looks may be deceiving dunno...might try to have someone I know look at everything electronically. (I know nothing of electronics and wiring)

UPDATE! found this old thread on here after some lurking. this is my jeep back when the previous owner had it. wow sounds like the transmission shop had no clue what they were doing...
http://www.naxja.org/forum/showthread.php?t=1031649&highlight=Orlando+transmission literally ....I have replaced every possible part on this jeep with the exception of the engine and tranny at this point.

Jolly_Red_Panda said:

UPDATE! found this old thread on here after some lurking. this is my jeep back when the previous owner had it. wow sounds like the transmission shop had no clue what they were doing...
http://www.naxja.org/forum/showthread.php?t=1031649&highlight=Orlando+transmission literally ....I have replaced every possible part on this jeep with the exception of the engine and tranny at this point.

Click to expand...

Sounds as if either the wiring was already messed up and it was hodge podged together or somehow the wiring or connection was messed up while pulling the old and installing the new transmission.

Can't think off hand any other mechanical issues other than the driveline line slip yoke, sometimes makes a clunking sound and needs to be greased. Then there are TC, brakes, axles, diffs, u-joints and driveline problems that sometime effect shifting.

Without any known mechanical issues along with a reference to that post I would assume some sort of electrical wiring issue and/or the wiring harness may need to be replaced or repaired.

yep. Its a good lead. Both axles, xfer case, both drive shafts have all been replaced. I had this shifting problem prior to all other drivetrain replacements. The original 231 case was beyond destroyed in this jeep. PO claimed that to be rebuilt as well. That's why I swapped in a 242 case. I know most guys would knock taking out a 231 and replacing with a 242 but I had one readily available works fine for a DD.