Cherokee XJ AW4 Woes

I have a 2000 Jeep Cherokee XJ with the aw4 transmission. I been looking around the internet for almost a year now for the problems I'm having but can't seem to find anyone that is having my problem.

So the problem, or problems:

When it's cold out the transmission will not shift until around 2500 rpms in 1st thru 3rd gear. This seems strange to me because everything I have read about this transmission is that it does not like heat.

My RPMs seem high in every gear. At 55 mph's I'm running at 2000 rpms. The fuel computer says I'm getting 21 to 24 miles per gallon on the highway, but in town it's like 11 mpg.

According to 3 different GPS units my speedometer is off like 5 mph, but everything is still stock.

When the transmission won't shift my oil pressure gauge maxes out until the transmission shifts.


I have changed the TPS as well as adjusted the kick down cable but nothing seems to make a difference. There is a strange sound coming from what sounds like the front end, almost like a bearing noise. When I put this transmission in I remember the torque making the same noise.

If anyone has any ideas I would love to hear them.

Thanks
 

jsexton

Observer
I've had 5 different cherokees... they all do this when you don't let it warm up long enough in cold weather.

Just let it warm up for a few more minutes, and drive it "softer" until it gets up to temp.
 
It is worst in the winter, but I should have mentioned that it does this even when its warm out side. just not as bad.

Thanks for the suggestion I will try this in the morning. Its supposed to be around 4 degrees.
 

jsexton

Observer
Also, if it takes a while to warm up (more than say 5 mins of soft driving), your thermostat might be stuck open too (which would make the problem worse)
 
I never thought about that. I pretty sure the themostat is stuck open becasue it never get close to normal summer time temp range. I think it may have moved to the second mark after 15 mins of driving. I will have to look at that.

Thanks again.
 

jsexton

Observer
oh it should be up to full temp after 15 mins of driving.

the good news is the thermostat is easy to replace and it should be around $15 for a new thermostat and gasket.
 

88Xj

Banned
Someone possibly bypass the trans cooler in the radiator and run just a aux filter? Thus fluid stay colder longer?

Also tran to pull the solidnoids and clean them, as well as a new filter & fluid? Would be good maitenance!
 

BIGdaddy

Expedition Leader
My AW4 has 204,000 miles and this is not something normal for mine. Just for reference.

I'd say maybe it's time to have a shop take a look at it.

If funds don't allow a professional installing parts and charging labor for a rebuild of some sort, maybe find another 2000 AW4 in a junkyard for a few bucks, and give that one a try. Get some beer and pizza, invite a few friends, and swap that sucker out on a friday/saturday evening.

Also, you can always consider an AX-15 5 speed swap.
 

d67u57

Adventurer
i had a few xj's
(all) when cold did shift a bit rough/late.

if you have a remote starter,engage it before you put on your coat etc.

one of mine,i used to warm it up a good 15 minutes before setting off.by the time i got to work,maybe an hour later it

would reach normal operating temperature...lol.
 
I did warm it up this morning for about 15 mins and it seemed to shift better. I still don't understand the oil pressure spike when it wont shift. I sold my 04 Wrangler and bought the XJ. I like the roomit has and there is no way I'm paying 40 grand for JK. I'm building a expo type trailer and I'm worried that the transmission will not hold up to pulling the trailer.
 

jsexton

Observer
The oil pressure goes up because the oil is cold (thicker). Put it in neutral and rev the engine, you will see the oil pressure climbs as the RPM's climb. As the engine warms up, the pressure will not rise as high.

Is this what you are experiencing?

I usually ran thinner oil in the winter because of this.
 

d67u57

Adventurer
once its fully warmed up..say after an hour driving around,find a hill and go at it.

very very slowly. see if it complains. stop.start.stop.start. if no problemo then youre golden.

remember,these things are bullet proof.unless you beat them to death.or drain the oil :D
 

MStudt

Adventurer
Try disconnecting your TCU and see if you can shift through all the gears. Also, is your AW4 a Renix? You should have an inline fuse located close to the TCU, make sure it's not blown. Another thing if you have a Renix, on some models there is another fuse located under the dash on the drivers. If either one of these fuses are blown, the TCU will not function properly. Thus, nit shifting properly. If you have a bad TPS, this will also cause poor shifting, or not shifting at all.
 

Lowrange2

Adventurer
Try disconnecting your TCU and see if you can shift through all the gears. Also, is your AW4 a Renix? You should have an inline fuse located close to the TCU, make sure it's not blown. Another thing if you have a Renix, on some models there is another fuse located under the dash on the drivers. If either one of these fuses are blown, the TCU will not function properly. Thus, nit shifting properly. If you have a bad TPS, this will also cause poor shifting, or not shifting at all.

His Jeep is a 2000. Far from Renix.

I have a 98, a 2000, and 2 1993 XJs and have not had any sort of rough or late shifting issues in any of them.

I'd look into the suggestion above.

Unplug TCU and see what happens then test TPS.
 
I will look into the TCU. This is a junkyard trany that I put in about a yeat ago. My brother says it is way better than the one we took out, but to me there was no diffference.

Just curious, but could a bad torque converter cause these problems.

And the other question why is my speedo off 5 miles and yes it was off with the other trany as well.
 

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