Newb here but I've been lurking these boards and using the "Search" function for the last 18 months since I purchased a 2002 Grand Cherokee with 101,000 miles on it. It's a 4.0L inline 6 engine. I do not know exactly what transmission I have but my VIN is 1J4GW4855 2C167427 and my pan gasket would be exactly square except for a 45 degree "shortcut" across one corner. From the time I purchased the Jeep it shifted into 2nd gear and then 3rd far too early. After shifting into 2nd and then 3rd too early from a dead stop the transmission would "toggle" (shift into 3, then back to 2 then 3 again) between 2nd and 3rd gear a couple times driving me crazy (and probably wearing hard on transmission internals). Occasionally on really hot days and typically if the AC compressor was running it would go into a sloppy version of "limp-home" mode out of the blue. That is to say it would shift into 2nd gear at a stop and shift 2nd to 4th unless I manually went 1, 2, D. Finally it no longer took a really hot day or the AC compressor to make this "limp-home" happen.
Not long after I purchased the Jeep I took a wild guess and replaced the rear vehicle speed sensor which changed nothing.
I know this similar issue has been posted on this board several times with the same "replace pressure solenoid and sensor" as the fix but honestly I haven't seen my exact running issues documented here. I today replaced the pressure solenoid and sensor just like the video seen here (not my video):
I'll add that using the cycle-the-key method I have never had any codes tripped on the dash (it only ever displayed "done"). I cannot say if there were hard fault codes store because I never hooked up to the OBD port.
In any case replacing the solenoid and the sensor fixed both the early shifting problem and the limp-home problem. I used OEM sensor, solenoid and gasket from my local dealer and spend $209. I hope this post helps anyone that might be Googling around for a fix for my same problems.
To sum up here are the specific gripes I was dealing with:
-early shift into 2nd gear and 3rd gear
-jump from 2 to 3 to 2 to 3 if I didn't lighten up on the throttle
-occasional limp-home mode on hot days at full running temp or before that if the AC compressor was running
-finally, limp home mode at all times operating the vehicle
Just for further clarification here are gripes that I did NOT
have and cannot comment on:
-slipping of transmission between shifts (have never had a slip even while towing)
-stuck in 1st gear (i have NEVER had mine stick in 1st)