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AW-4 4wd problems

C

cherokeeproject

NAXJA Forum User
Location
Cypress, TX
so i have had some recently developed problems with my jeep but first here is some background info.

96 jeep cherokee sport 4x4
2" lift
AW4 auto tranny
HO 4.0

recently my jeep has not been accelerating like usual. when i take off from a complete stop it will accelerate normally until it tries to shift into the next gear. it will then rev up the RPMs past the normal shift points (sometimes to redline and hold it there) and shift hard into the next gear. also, during freeway driving while in overdrive, when i go to pass (pedal to he floor) it will not accelerate like it used to. the rpms will slowly go up and it seems like im accelerating at a rate of 1mph / min. occasionally when i put the pedal to the floor it will just jump up the RPMs to redline and never accelerate.

this to me seems like either torque convertor problems or clutch plates internal to the transmission, or possibly the planetary gear.

i serviced the transmission about 8 months ago and put new fluid and filter in it. (ATF +4)
i checked the fluid and it is still red in color, just like when it was new. i also checked all my other fluidlevels and they all seem to be fine.

has anyone had similar problems? what caused it? and what did you do to fix it?

thanks in advance
Josh
 
thanks joe. i tried doing a search for "AW4" and all its variations but for somereason the searches came back with nothing. i know this isnt right cuz i have seen tons of post on this transmission.
 
cherokeeproject said:
thanks joe. i tried doing a search for "AW4" and all its variations but for somereason the searches came back with nothing. i know this isnt right cuz i have seen tons of post on this transmission.
Click to expand...

The NAXJA search engine can't handle three character or less searches. There is a sticky on searching FAQ.

For short items go to Google and enter "AW4 naxja" and it will get the results, same for TPS, EGR, etc. Without the quotes!
 
cherokeeproject said:
so i have had some recently developed problems with my jeep but first here is some background info.

96 jeep cherokee sport 4x4
2" lift
AW4 auto tranny
HO 4.0

recently my jeep has not been accelerating like usual. when i take off from a complete stop it will accelerate normally until it tries to shift into the next gear. it will then rev up the RPMs past the normal shift points (sometimes to redline and hold it there) and shift hard into the next gear. also, during freeway driving while in overdrive, when i go to pass (pedal to he floor) it will not accelerate like it used to. the rpms will slowly go up and it seems like im accelerating at a rate of 1mph / min. occasionally when i put the pedal to the floor it will just jump up the RPMs to redline and never accelerate.

this to me seems like either torque convertor problems or clutch plates internal to the transmission, or possibly the planetary gear.

i serviced the transmission about 8 months ago and put new fluid and filter in it. (ATF +4)
i checked the fluid and it is still red in color, just like when it was new. i also checked all my other fluidlevels and they all seem to be fine.

has anyone had similar problems? what caused it? and what did you do to fix it?

thanks in advance
Josh
Click to expand...

Just had a problem with mine shifting really hard through the gears. Nothing to the extent of your problems. But trying adjusting the kickdown cable

here's a guide: http://www.allpar.com/SUVs/jeep/cher...nsmission.html
 
yeah, do a little homework - here and googlie - I had all sorts of troubles when I didn't know anything about the tranny - replaced all sorts of things, and adjusted all sorts ofthings. now it shifts better than my mothers caddy...
 
Throttle position sensor can be tested with a meter and a manual. I would definitely recommend doing this.

That being said, I'd get the ATF+4 out of there. People have had mixed luck with it whereas there is never a problem with the Dex/Merc III which is what your AW4 is designed to use.
 
so i took the jeep out today to get better diagnosing info and... when the transmission is in "power mode" or basically when im hard on the throttle the transmission wont shift. it will only rev up the RPMs and hold them there. on both freeway and in town driving. i tried shifting manually and it was doing the same thing. still sound like the TPS?

i was hopeing it was something simple so i adjusted the throttle cable but it still didnt solve the problem.

now im down to replacing things i think....

as for the fluid it seems like the difference is only a matter of opinion. some people prefer the ATF and some prefer the dextron/mercon. the manual states that a mopar mercon should be used. but from the research i have done there isnt much difference in the two. im ganna keep looking and find out the specifics and make a decision on my own.(additives, viscosity, etc) if anyone has any links to some purely scientific based research (non-opinionated) on the fluids please post them. they will be appreciated.
 
Do you have evidence that you shouldn't use coolant instead of Dextron III?

nope... but you still shouldn't. Dextron III is recommended, ATF+4 is not.
 
i find this a little odd. im not doubting anyones opinion here, but after rechecking my owners manual for my 92, the back says ATF plus type preferred, however else where in the manual, it says Mopar Auto trans fluid or equivelently labeled Mercon or dexron. ive seen this confictly fluid types elsewhere, and ive just stuck with plus type. ive been running it for at least 40K with no problems to speak of. just my 2 cents
 
birchlakeXJ said:
Search on this forum and others for reasons why you should use Dex III in the AW4.
Click to expand...

ive done quite a bit of searching and to me it all seems like its just a mattter of opinion. ya granted alot of guys that have run ATF have had problems but so have guys that have run mercon. but i dont want this thread to turn into another rant on tranny fluids. there's already plenty of them.

i called O'rileys about the TPS and they quoted me $49.99 unfortunately i couldnt get over there before they closed so i'll have to head over there tom. and i have most of my day availale so i'll install it as well and see how she does.
 
cherokeeproject said:
ive done quite a bit of searching and to me it all seems like its just a mattter of opinion. ya granted alot of guys that have run ATF have had problems but so have guys that have run mercon. but i dont want this thread to turn into another rant on tranny fluids. there's already plenty of them.

i called O'rileys about the TPS and they quoted me $49.99 unfortunately i couldnt get over there before they closed so i'll have to head over there tom. and i have most of my day availale so i'll install it as well and see how she does.
Click to expand...

I see where you posted earlier that you tried shifting manually--that was with the TCU unplugged, right?
 
so i checked the voltages on the current TPS and they were reading within normal ranges (+/- .5v) i also checked it against a brand new TPS which read a little bit higher voltages but still within the normal ranges, the ground was good as well. i even test drove it with the new TPS and i was still having the same problems. so the TPS has been ruled out as a possibility.

im out of time for today but it is my plan to readjust all of the cables and try it again...

any more suggestions?
 
The issue with the ATF4+ is that it has a lower coefficient of friction than Dexron III (which supersedes the IIe in the owners manual and stamped on the tranny drain plug). This can lead to excessive slipping and extra heat generated, and indeed that is the usual complaint from those I've seen have problems with it in an AW4. Does it have problems shifting with the tcu unplugged and you shifting manually? A fluid change may help if it is a slipping problem.

On a related note, when the Chrysler trannies first came out a large number of them were killed by shops that put Dexron in them. The higher friction coefficient in the Dexron caused clutch chatter which destroyed the facing material in a very short time.
 
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