I tried searching and found similar issues but nothing quite the same although I'm sure I overlooked somewhere, but I figured I would let you know I did search. Anyways...
working on my 96 xj with aw4
trans has been acting funny since I got the thing back in September when it would shift in and out of overdrive and would stack shifts. Owning a blazer with the 700r4 I assumed it was the TV cable so I adjusted it back to oem specs and it worked fine for a while but still wasnt perfect so I checked fluid and it was about a pint low so I topped it off with some trans-x to smooth it out for a while. This helped for a little while but here the other day when it went into overdrive and when i would let off the accelerator even just a slight ammount it would downshift regardless of vehicle speed and give it more accelerator it would go back into overdrive until it completely lost overdrive. I rechecked the tv cable and it was a little out of whack so i readjusted it and it went back to the same accerator issue and lost it again. there are no codes thrown. all other gears work great. other thing i might add is the reverse lights have never worked. any ideas? I'm a noob when it comes to the aw4. thanks everyone

 

1. The AW4 is electronically controlled and the "throttle position sensor" is directly involved with its operation. I would test and or replace the TPS. Below is more on that very important sensor.

2. Another possibility is the neutral safety switch, which can be involved with certain transmission issues. And the fact that the reverse lights don't work can often directly be linked to the NSS as they are on the same circuit. Here is a link on how to "refurbish" the NSS. It can often (not always) return function to the reverse lights and the NSS.

http://bc4x4.com/tech/2010/jeep-neut...ty-switch-nss/
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.

The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -

NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!

• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted accordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the denied acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.

 

strange... i'll have to bust out the meter and test the tps and may as well pull the nss out and clean as well. odd that it runs great and no codes but a tps could be the issue. i'm new to the 4.0. thanks!

 

NSS was clean so I adjusted it and it fixed the reverse lights.
tested the tps and there was a slight flat spot around where i would presume cruising throttle to be so I replaced it and it seems to shift a tad smoother. I also went ahead and went one more click than stock on the TV cable adjustment and its more firm. Now to change fluid/filter and brake clean the valve body and what i can reach without pulling the trans. Excellent help tjwalker!

 

Glad I could help. Sounds like you have things under control. Enjoy your XJ!

Be sure to use Dex/Merc III compatible fluid in your AW4, no matter WHAT the parts store or dealer says. There was a bulletin a while back about using ATF+4. While some AW4 transmissions tolerate this fluid, not all do and you can end up with slippage which has directly been traced to this fluid. Why would you want to take the chance? Use Dex/Merc which is what the manufacturer of this transmission (Asin/Warner) recommends. And still recommends.

Dex/Merc III compatible. (licensed Dex/Merc III no longer exists). Accept no substitutes.

 

Is Dexron III/Mercon okay?

 

dropped the pan yesterday evening. the dipstick tube wouldnt come apart so i figured i'd snake it out still attached but then the downpipe and crossmember both hindered the removal. i unbolted the downpipe from the manifold and used the ratchet strap method i read on here around the axle tube and got it to squeeze past the crossmember but still not able to drop past the downpipe. didnt really want to pull the crossmember and go the other way with it but looks like i may have to. its warmer today so I'll report back tomorrow. may just cut the downpipe and weld it back together haha

 

would have been done with it yesterday but I made an idiot mistake and when I cut the exhaust right after the bend to return running to the rear before the crossmember I cut clean through one of the transmission cooler lines. Looked everywhere in my garage for a small piece of trans cooler rubber hose and couldnt find anything so had to snag some this morning. The old filter was near plugged up on the inside screen but had the normal mess on the magnets in the pan and on the pickup screen. i'll keep posting till the solution is made

 

The AW4 tranny dipstick tube can be a pain. They are a two-piece tube that has a rubber o-ring in the connection that can stick. The thing I did my first time was to re-connect the top of the tube to the block, spray the connection with some PB Blaster, let it sit for a bit, then get underneath and grab hold and gently twist the pan back and forth while pulling downward. After you finally get it apart, pull both pieces out, gently remove the o-ring and use a wire brush to remove all the gunk. Before you put it back in, use some grease on the connection and put the o-ring back on (if it's usable). I then bolt the pan back up and lastly, from the top, gently push the top part of the tube into the lower while gently twisting. Then reattach it to the engine. Next time, start with removing the top of the tube first, with the cleaning and the little bit of grease, it should be MUCH easier to get apart.

 

Got everything buttoned up and back together. Had the trans a little over full as I read everywhere on here to check while at idle in park. Drove around a bit and it would shutter and slip up then down a gear. Pulled my dipstick and low and behold it says to check while at idle in Nuetral. Got it level on fluid and took it for a spin later and it still was a little iffy. would slip every once in a while and then work perfectly fine. I then took it out on the highway and everything worked great for about 6miles even overdrive was working great and I made it where I was going and get out of the jeep and it reeks of burnt fluid. Turned out to be fluid from working on it burning off of the exhaust. Headed home and it lost overdrive again. Today the trans has returned to working fine. Only thing I can gather is the previous owner drove the thing for quite some time even when he brought the thing to me when i traded him my car for it which was a 200mi trip with a messed up temp gauge no coolant in the overflow. The day after I got it i took it wheeling for the first time and it blew the end tank off the radiator and there was a patch job on the tank of silicone and epoxy so I'm assuming the trans cooler was doing much "cooling".
I think I'm going to start looking for another aw4

 

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

this link lets you know what aw4s are drop in and which ones will need modifications.

 

hrmm....may try unplugging the electronics and see what happens. I know od wont work but I hardly ever drive the thing on the highway