Mechanics

AW4 TRANSMISSION SHIFTING PROBLEM

2001 Jeep Cherokee • 198,000 miles

Transmission will not go into reverse gear when first started in the morning. Also when shifting into drive, it hangs in current gear until I let off the throttle slightly. After trans temp. Warms up (5 miles or so), the trans begins to work fine with reverse but slightly rough shifts. Shudders if rapidly accelerated from standing stop.

Work performed:
Valve body replaced (improved shifting into reverse but RPMs need to be a little high and it is sluggish) sometimes it will jerk into reverse around 1300 RPM if it was just driven recently
Trans oil: Toyota DII (level is correct)
Solenoids checked (13 ohms)
There is a fault code in the output speed sensor circuit (P0720)
Disconnected TCM and tested: same results
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Desertjeeper
March 23, 2012.




Have you checked the transmission line pressure yet with a pressure gauge?I always do that before replacing anything. Also have tried to diagnose the P0720 yet?


Saturntech9
Mar 23, 2012.
Have not checked line pressure yet. The P0720 code may be coming from the wiring itself. Its been awhile since I checked but I think it was over the 5 ohms for any part of that circuit stated in the powertrain and diagnostics manual from jeep. The sensor, when checked with a multimeter, puts out a beep every time the rotor passes by it (am I correct in thinking its an induction type?). When I get some time, I plan to repair that wiring harness.


Tiny
Desertjeeper
Mar 23, 2012.
Which model cherokee do you have classic sport etc?Also what size engine do you have?


Saturntech9
Mar 23, 2012.
2001 Jeep Cherokee 60th Anniversary Edition. VIN puts it down as Sport. Engine is 4.0L 6 cyl 242 naturally aspirated.


Tiny
Desertjeeper
Mar 24, 2012.
I posted the trouble tree for code P0720 lets follow that trouboe tree and see what you find.I have seen output speed sensor issue cause transmission issues.


Saturntech9
Mar 24, 2012.
Thanks alot, I will do this sometime this week and I will get back to you with results.


Tiny
Desertjeeper
Mar 24, 2012.
Alright let me know what you find.
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Saturntech9
Mar 24, 2012.
Went through this procedure and stopped at #2. When vehicle is lifted, I am getting vehicle speed reading. Something else has started to happen though. The other day, after just starting and coming to my first stop, the vehicle started to shudder and die. This is a new twist in the chain, and now I am starting to think maybe torque converter clutch is not engaging/disengaging. Already changed the solenoids since they come new with the valve body and I checked them with DVOM before installing. When is the TC supposed to be engaged/ disengaged?


Tiny
Desertjeeper
Mar 31, 2012.
The tourqe convertor should be disengaged when you come to a stop and engage when your at cruise. When it starts to die when coming to a stop try putting it in neutral see if it still dies. ALso any new codes?Lets also finsh looking at that code P0720.


Saturntech9
Mar 31, 2012.
Been putting it in neutral to keep it from dying when I feel its going to happen, keeps running when I do that. The reason I stopped at #2 because it says that if, when monitoring output shaft speed it's above 0 RPM then the code will not set. Just so that I'm not confusing this, I just used my code reader to monitor vehicle speed. I have Auto enginuity's program but did not use it. I may be able to monitor OSS from it but I have to check.


Tiny
Desertjeeper
Mar 31, 2012.

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