aw4 problems

i had a guy change my transmission fluid and filter on my 1990 jeep cherokee and ever since going down the road my transmission will jump from 2000 rpm to 4500rpm and stay there untill i mash the gas and hold it then it will shift back down . thinking he had put cheap atf in it i changed my fluids and filter but it still does it. any suggestions why.

I'm not exactly sure that I understand what you're saying here, but here's what I'm getting out of it: You're cruising along with the engine RPMs around 2000, the transmission suddenly downshifts and the RPMs kick up to around 4500, then you floor it, the engine RPMs go to the redline and the transmission upshifts, and all is 'normal' again. Does that sound about like what is happening?

Any other details you could provide will make it easier for us to help ya... like speed you're going, level ground? going uphill?, does it happen consistently or is it totally random when it does it?

YODIE213 said:

i had a guy change my transmission fluid and filter on my 1990 jeep cherokee and ever since going down the road my transmission will jump from 2000 rpm to 4500rpm and stay there untill i mash the gas and hold it then it will shift back down . thinking he had put cheap atf in it i changed my fluids and filter but it still does it. any suggestions why.

Click to expand...

You may have a TPS (throttle position sensor) issue affecting your AW4 shift points. But I agree with 98JeepXJ that you should try to explain more clearly if you can.

Thats the EXACT same problem as I had. My problem WAS the TPS, adjustment is critical. Another way to verify this is to remmove fuse going to TCM (Tranny Computer under PAssenger side dash panel. If you remove the fuse and you can shift the tranny manualy without the problem, it is electrical. Just be sure to remember to downshift manualy when comming to a stop to prevent overheating of tranny and stalling.

Bob

Well, when I first read it, my initial thought was TPS. But then I realized that he said that it has been doing it EVER SINCE the fluid was changed, I dunno if anybody else saw that. Thats why I didn't jump on the TPS bandwagon. I know it's entirely possible that the TPS crapped out right after the fluid was changed, but still there wasn't enough clear information for me to condemn the TPS...

its a very radom problem. ill change my tps as soon as i get the engine to run again. you know the usuall, cranks but will not start. the dodge dealer down here told me i might have to flash my transmissions' ecm to update it because of the cheap tranny fluid that was ran through it. ever heard of that before? thanks cecil

Exposing himself to the TCU (not ecm) won't do any good! There isn't an eprom in it to flash. I would not go near that place with a ....well you know what!

The only thing that would get flashed is your cash! No sensors to determine what kind of fluid was used is in any automotive vehicle that I know of.

If you have not changed your TPS yet, it is past time anyway. You should also replace other sensors to eliminate them as contributors. If it won't start, replace the cps as well.

I would try the fuse removal suggestion inspite of the random behavior. you won't hurt anything driving it in semiautomatic mode.

What does your fluid level look like?

my fluid is new now and so is my filter. looked like he just changed my fluid and not the filter. my cranks and wouldnt start was just my crankshaft postion sensor gone bad. the wires somehow got on the exhaust and burned off. a quick wire tie and a new sensor will stop that from happening again. runs great, other than ive blown a head gasket. one right after the other but the way i figure it, ill eventually have a new one after a while. thanks for all your help so far.

i have a 89 jeep and my tps was shot i found this out after replacing my trans (from a junk yard ) with the help of a friend and well long story short it was the throttle position sensor, so look up online i found lots of info as in how to test the tps sensor was super easy then i picked on up from used jeep for $5.00.
Mine was doing all the same as yours varying and reving at weird times etc

And the newbie steps up with a 4.5 year old thread resurrection! Good job.

wombat88 said:

i have a 89 jeep and my tps was shot i found this out after replacing my trans (from a junk yard ) with the help of a friend and well long story short it was the throttle position sensor, so look up online i found lots of info as in how to test the tps sensor was super easy then i picked on up from used jeep for $5.00.
Mine was doing all the same as yours varying and reving at weird times etc

Click to expand...

great! welcome!!!:wave1: