Transmission issue

[hammertech]

Anybody come across this problem before. I have a 03 JGC laredo 4X4 I-6 82000 miles. When traveling at 55-60mph the transmission seems to shift in and out of overdrive. I have not changed the fluid yet, but I was reading the manual and it refers to doing a band adjustment at 80000 miles. Does this have to do something with the band adjustments? I also noticed today if i give it more throttle when it starts hunting it will continue unless I back off or romp on it into passing gear. Any info would be much appreciated.

 

[B192734]

My 00XJ jumps back and forth like that, but generally only when I'm climing a pretty good size hill out on the freeway. I normally just hit the throttle a little and keep it out of O-Drive until I hit the top. I think that mine is just trying to keep up speed while climbing. It just hits the right spot and wants to shift into overdrive because it doesn't need to work so hard, but then overdrive isn't quite enough to keep it going so it shifts back.

 

[hammertech]

Thanks B192734

I changed the filter on the transmission friday and noticed it did not shift in and out of O.D. as much. Today I had a thought to check the speed sensor in the rear of the trans before the transfer case. I found some debris on the sensor, so I cleaned it off and the weird shift is pretty much gone. Thanks for the help.

 

[hammertech]

Ok! Here is an update....
The problematic shift is back. After some extensive test drives, it looks like the GC wants to down shift but can never complete the shift unless you give it more pedal. I have checked and adjusted the kickdown cable according to the jeep stealer shop manual. I have also changed the speed sensor, Pressure/Temp sensor, and govenor solenoid. After all this it seems the problem still persists.

Problem #1
Recently I have noticed that if I hold it steady at 70mph (2000rpm) you can feel the GC surge. The speed does not increase but the rpms will jump up to 2100 then right back to 2000. Its almost like it is about to start to down shift then it doesn't.

Problem #2
If I come to a stop after driving on the highway for about 10 miles it is OK, but when i release the brake to takeoff it feels like the trans slips(or a jerk).
If I make a few more frequent stops it will go away.

Problem #3
When on the highway anywhere above 50mph the GC attempts over and over to downshift and only competes it if you accelerate or it will stop if you decelerate.

Does anybody have an idea what could be causing this? The one sensor I have not checked is the TPS. Could the TPS cause these problems?
Please help this GC has a mind of its own.

03 GC 42RE NV242 4.0L 84K

 

[TwistedCU]

I really wish I could help you, but sensors and electronically controlled stuff is heap big magic to me...

Perhaps you might want to search this forum:
http://www.nagca.com/forum/
If you don't find answers, then post your question there. there's alot of very informed GC members there.

I am by no means trying to run you off, we're glad to have you here on Jeepz, but I see you haven't gotten much help so I hope the link above will be helpful.

 

[droopey]

Have you checked the fluid level?

 

[hammertech]

Yes. The fluid level was checked when I changed the filter, and was checked again when I installed the pressure sensor and govenor solenoid.

 

[tardis454]

My guess is Gorvernor solenoid, and/or governor pressure sensor. That's the weak link on ZJ/WJ 42RE transmissions. Your downshifting problem is the first indicator of this. The governor is a valve that tells the transmission how fast the car is going. A spring loaded valve opens in proportion to how fast the governor is spinning. The faster the governor spins, the more the valve opens. The pump feeds the governor via the output shaft. The faster the car goes, the governor valve opens, and higher fluid pressure is let through. Bogus Governor Solenoid/sensor=bogus trans performance, or eventual failure...
I've done my share of transmission teardowns, let me know if you need more info.