AW4 Shifting Problem

TrailHunter · Jul 1, 2004

This problem is largely intermitent. It will have the problem for a week and then go a month without a wink. I've searched already and I coudn't find a similar problem.

Rather than shifting based on throttle position, it shifts at fixed speeds. For example it does the 1-2 shift at 15mph, the 2-3 shift at 25mph and the 3-4 shift at 35 which makes getting on the free way really tough. I can manually downshift it. When cruising at 40 or so and mash the gas, it doesn't down shift.

Does this sound like the TPS?

Darky · Jul 1, 2004

that's weird, I have never heard of anything like that...lotta help that was huh?

scoobyxj · Jul 1, 2004

did you check the kick down cable on the throtle body? they will slip mine did, but it never acted like that cought it before it got farther than a click or two.

TrailHunter · Jul 1, 2004

I have checked that KD cable and it seems to move around a lot. Correct me if I'm wrong, but it is self adjust after it's reset correct? It's a matter of pressing that button to push the "plunger" back in and then it will move out to the correct position when you drive it. I did this a while ago and my memory could be off about how to do that. The kickdown cable should not afect upshifting should it?

CLb33fyXJ · Jul 1, 2004

no the tv cable will affect the trans downshift

ARP · Jul 1, 2004

Ive always adjusted the kickdown cable by depressing the button and getting someone to press the gas pedal to wot then release the button. This is based on nothing but my way of doing it , all applicable cautions apply. For me WOT by hand at throttebody isnt the same as WOT by foot at pedal the difference is 1/2 inch or so....

scoobyxj · Jul 1, 2004

as far as the way to set the tv cable i dont know. i just set mine back where it looked like it was [discolored plastic]. the speeds you quoted earlyer sound like where mine shift, except at w. o. t. where the tv cable will change the shift points. mine is a 2000 if it matters.

TrailHunter · Jul 1, 2004

I'll definitely try to adjust the kickdown cable in that manner, but I'm more interested in the upshifting problem. I'll adjust the cable and get back to you if it makes a difference.

Mine is an 87 with plenty of miles on it. I thought the AW4 shift timing was controlled electrically. I really don't know how all of these things work together so I'm doing my best.

scoobyxj · Jul 1, 2004

sorry should have reread your question mine dose do the 3-4 shift at about 35 an locks the t. converter up at 45. what about the pump could it be getting weak or dirty filter? anyone?

TrailHunter · Jul 1, 2004

I've done a filter/fluid change about 12K miles ago, the fluid levels are correct.

scoobyxj · Jul 1, 2004

it may be computer controled but not to my knowledge. not shure how the t. converter is controled though mine will lock up in 3rd if i have it in 3 mabey yours is locking up to early.

TrailHunter · Jul 1, 2004

It might be locking her up early. How can I tell, and why would that be bad if locks up when in fourth? Also, that wouldn't explain the first two shifts.

scoobyxj · Jul 1, 2004

it isnt bad just anoying and it locks up to give you better gas milage in forth

Coop · Jul 1, 2004

There is a TCU (transmission control unit) under the dash on the passenger side. This unit controls the transmission using input from your TPS, speed sensors, etc. It is entirely possible that it could be malfunctioning or getting bad readings from any of the other sensors that feed it info. Hope you find the problem. The power comfort switch also changes shift points via the TCU.

dusterboy71 · Jul 1, 2004

Sounds like someone "bumbed" the [power/comfort] control and it's now working in "comfort". Did that before on my "88!

TrailHunter · Jul 1, 2004

The comfort/power switch isn't the issue. It shifts the same on both settings and when it's working normally and it's set to comfort, it shifts much more aggressively than it does now.

Tim S · Sep 5, 2004

did you ever fix the early shift problem
My jeep has the same thing going on
Thanks
Tim
[email protected]

TrailHunter · Sep 6, 2004

Unfortunately, I have yet to fix it. I've been to busy to really get into it yet. I'll post it here when I figure it out.

MACH90XJ · Sep 6, 2004

Take some readings of your TPS,it definately has alot to do with your shifting points.Aside from fluid level problems ,most shift problems in the '87 to '90 years are TPS related.Heres a link for reading,Good luck.

http://members.tripod.com/BillyXJ/SENSORS1/index.html

tchase · Sep 7, 2004

MACH90XJ said:
Take some readings of your TPS,it definately has alot to do with your shifting points.Aside from fluid level problems ,most shift problems in the '87 to '90 years are TPS related.Heres a link for reading,Good luck.

http://members.tripod.com/BillyXJ/SENSORS1/index.html

Agreed, sorry I've been away on vacation, but one of my three TPS failures produced symptoms like this. Very low shifts, no kickdown or change in shift points at WOT. Would manually downshift fine. I actually still keep this TPS as a spare because it's better than one that has failed and goes all the way to redline before shifting.

Tony
'91 4.0 AW4

AW4 Shifting Problem

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