XJ AW4 issues/questions for trans pros.

88jeepster

88jeepster

Jesus, Jannette & Jeeps for Life!
Banned
Joined
Feb 16, 2012
Location
Boone, NC
hey guys. my trans shifts perfectly fine but I know for a fact something is holding it back in drive like majorly. it doesn't accelerate hardly at all and you can tell its like I've got a trailer behind it the whole time. no codes except for PRN switch is bad and had a code for speed sensor, which speedometer always works, but cleared that and hasn't come back. only code is for O2 sensor bank 2 by the cat is bad but that's it. and also if in 4wd starting on hill, doesn't seem to start in 1st even when in 1st so any ideas. I want to say TCM is bad but anyone have this issue before. first encounter with AW4 trans issues. Driving down the road fairly easy on it you would never tell but try to get on it and its like a tank is dragged behind it. any help would be great. thanks for any help.
 
pull the pan, if there is any metal in it, the overdrive planet/sungear/drum are most likely going bad. if the pan is clean you may need to start with a prndl switch, and just because the the speedo works doesn't mean the speed sensor is good. the trans most likely has a speed sensor and the speedo works off of the t-case. if the speed sensor is bad it can cause 2nd gear starts. the tps can also cause this problem, and remember some jeeps used dual sided tps systems.
 
Sounds like a clogged cat. Hear any rattles at idle or real light throttle?
 
ok so 1. no cat, 2. changed filter and fluid with lucas 2weeks ago and shifts even better, 3. adjusted PRND switch and starts normally now without using starter switch that I put in and reverse lights work again, and 4. still doing it. haven't messed with speedo sensor but I'm working on getting a new or used one soon. u mentioned TPS earlier, any way to test these since they're not adjustable on these newer xjs. it just doesn't have the symptoms xjs usually give when TPS goes bad but could be a new one for me. thanks for the help. my blower motor transistor is bad (would that effect it) and the 4wd lights on dash don't work so could that sensor on the t-case have anything to do with it? thanks
 
Sounds like TPS to me. When it goes it can make a jeep do crazy things. I thought for sure I'd need a transmission mine was acting so bad. Jeep wouldn't go hardly at all, had no power if it even started, would get stuck in OD. Changed the $40 sensor and it ran like a new one.


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well I got about 9 different throttle bodies laying around so I reckon I'll get to swappin one at a time, nothing to lose but few moments swapping. Gracias
 
ait so put new TPS on today and New downstream O2 sensor since that was missing and runs much better but still doesn't have the full power that it should but I think i'm in the clear as far as trans issue cause TPS did make it shift stronger and downshift better so maybe it's a engine/sensor issue that I'll have to keep digging at. Thanks for the advise on TPS, wouldn't have guessed that but immediately made a difference. Thanks for the input to all.
 
Want to sell any of those throttle bodies?...or trade 4 for one of my bored out ones?
 
sure I'll sell some. I have one bored out already cause I tried to do one myself but the rest are there.
 
What size tires & what gears in your axles?
 
just stock 235s and 3.54s. it's running pretty good now. TPS fixed most of it and new O2 sensor. I'm still twerking with a few more things but for the most part it was TPS holding it back I reckon.
 
hey guys one more question please..i hear the 98 AW4 has 2 transmission speed sensors and then the one vehicle speed sonsor(on Tcase housing) so which transmission speed sensor would I start with. I see 3 sensors on drivers side of trans. 1. towards front, 2 at the rear (one goes down into trans and one above it goes into side) any ideas from anyone would be great. never had to mess with any of these but I guess 360K miles, it's time to mess with them.lol. thank you
 
The valve body wire harness can fail over time also. I have seen numerous times where the harness can no longer carry an electrical load to the shift solenoids. It doesn't go "open", but instead the solenoids and/or speed sensors do not read/react properly.
To test the harness circuits, you need to introduce an electrical load onto the circuit with a 12 volt bulb wired into a jumper harness. Remove harness, rig up a section of wire with a 1157 type of bulb between the power source and the harness and then provide a ground. See if one of the circuits makes the light burn dimmer. That would be the one that is no good.
 
hey Jody, sorry man i'm not fond of wiring so bear with me. unplug harness and test each wire? or just the power ones from the wiring schematic? I suck at wiring...
 
No, we are talking about the internal wiring harness that powers the shift solenoids and internal sensors. Remove pan, filter and then remove harness. Lay the harness on a table and introduce 12 volts (FROM A BATTERY) to 1 wire at a time while grounding the other end of the wire. But you must wire in a 12 bulb so you can see the harness' ability to carry the load of the bulb.
 
ohh well darn. aright i'll have to get to it when I can park it for a day. thanks for the info. good to learn this new info of transmissions. thank you
 
Jody Treadway said:
No, we are talking about the internal wiring harness that powers the shift solenoids and internal sensors. Remove pan, filter and then remove harness. Lay the harness on a table and introduce 12 volts (FROM A BATTERY) to 1 wire at a time while grounding the other end of the wire. But you must wire in a 12 bulb so you can see the harness' ability to carry the load of the bulb.
Click to expand...
You could also use a power probe hook or amp clamp lol.

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Lol. Understood.
If you haven't tried the hook its got a great vref feature. Also have been using it for all our parasitic draw issues.

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