PDA

View Full Version : Cherokee XJ AW4 Woes



robertwalker2003
01-22-2013, 03:14 AM
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
01-22-2013, 03:18 AM
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.

robertwalker2003
01-22-2013, 03:21 AM
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
01-22-2013, 03:28 AM
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)

robertwalker2003
01-22-2013, 03:31 AM
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
01-22-2013, 03:35 AM
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
01-22-2013, 05:20 AM
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
01-22-2013, 03:04 PM
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
01-22-2013, 10:47 PM
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.

robertwalker2003
01-23-2013, 02:09 AM
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
01-23-2013, 04:42 PM
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
01-23-2013, 07:15 PM
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
01-23-2013, 07:32 PM
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
01-23-2013, 09:02 PM
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.

robertwalker2003
01-24-2013, 03:13 PM
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.

MStudt
01-24-2013, 04:15 PM
Do you have stock tires or larger tires?

What did you pull the AW4 from?

There are many things that can be causing it. But yes, a bad torque converter could cause some issues. It could also be the neutral safety switch, which tells the computer which gear you have the shifter in. Could be the fact that you need to adjust your TV cable some.

T&A-XJ
01-25-2013, 05:37 AM
Change the fluid and filter. I had an AW4 that shifted a little weird and also would start to make a minor bearing noise at hiway speeds. I changed the filter that everyone told me was pointless and it shifted better and the noise went away completely.

Of that doesn't do it, test the wiring to the solenoids for damage/bad connections etc and then operation of said solenoids. Sounds like they are sticking to me especially with the temp changing their operation. These are accessible under the filter when you pull the pan and you can trace the wiring right as it enter the transmission on the drivers side. The harness connector is right under the tranny dip stick on the passenger side of the firewall.

Also not sure if it aplies to this tranny but moving the shifter to neutral while warming up your engine after it sits for a while will start pumping the fluid through the tranny so it not "dry" when you drop it in drive and take off. This info is regarding dodge trannies but I'm sure it wouldn't hurt to test out(assuming your parking brake works well and you park somewhere flat).

grainofsalt
01-26-2013, 06:37 PM
I'd recommend changing the transmission fluid. The filter is just a wire mesh so you could back flush it with some gasoline to clean that out.

As for your speedometer being 5 mph off, I think it's normal, with a 235/75R15 Or 30" tire it'll read correctly. The speedometer gear is in the transfer case, Not the transmission.