Have a 2006 Jeep Grand Cherokee 4AW with 80 Plus thousand miles that without any warning will not downshift out of overdrive when coming to a stop, I use the Vehicle for church and need it working correctly. I have tried to manually down shift it when this happens by pushing the shift level sideways and I get no response, If I turn the Vehicle off and restart all is well, sometimes for hours and others for just a few minutes. I was told it could be the SIM/ESM but not sure now. I had an Issues opposite of this a few years back where all the shift indicators had a box around them and it would not shift out of first, again turn vehicle off and restart and all was well, that issue has never returned, Yesterday the Jeep failed to downshift again when heading to church, had not run more then 5 minutes , I turned off and restarted and this time the check engine light came on ? I have at times had the tyranny bang and then the downshift didn't work but most times I get no notice at all. I also know this vehicle has SIM/ESM issues as well but don't want to guess at the problem as some of the symptoms suggest solenoid. As far as I know this vehicle has never had the fluids changed as the book states 90K so I assume both interior and external filters have not been changed as well.This Jeep has the Mercedes Trans. Thing is only worth 5000 so can't spend to much on repairs , plus on a limited income as a disabled Vet, What do you suggest.

 

James, Aside from reading the book to determine when to change fluid/filters, what have you checked? From your description, it sounds like it may already be too late for simple solutions.

 

Book states Trans filter and Fluid change at 90K, Jeep is 1K short of the suggested change, Further the 2006 Jeep Cherokee does not have a dipstick to check fluid levels, dealer wants almost $200 to change it, I'm told a power flush would be the best way to go, Jeep does have trans cooler as well. I drove the Jeep today with no issues what so ever. When I had this issue a few years back and took it to the dealer they said the code in the computer did not tell them what the cause was and they could only guess what to do, try replacing the ESM at a cost of $700, or another module at the trans was $1200 but they had no idea what the problem was then so I assume the same will be true now. Today while out I manually shifted thru 1-OD and it worked fine, On the Xway I manually shifted from 3-OD and it worked as it should, At 80 MPH in 4th the RPMS were 3K RPM's, when I put it in OD it Dropped to 2.1K RPM's. Any Thoughts ?

James

 

Unless you have a 5-speed trans, 4th gear IS overdrive. It sounds like it was in 3rd gear to be taching 3 grand at 80.

Okay, just looking at the specs, You must have the W5A580 5-speed transmission. Judging by the rpms, it looks like it jumped from 3rd to 5th when you engaged the O/D.

 

I shifted through all the gears 1st 2nd 3rd 4th and drive the display shows one two three four and drive, as stated it shifted through all the gears took it out today and it drove perfect on the expressway went through every gear., as stated when I do have the issue where it will not downshift out of overdrive I have to turn the vehicle off and restart it then everything is fine , what are the possible issues

James ​​​​​​J

 

I can't say for sure because the 5-speed transmission is beyond my knowledge, but it sounds like the overdrive solenoid is not disengaging the overdrive clutch. When this happens with the torque converter solenoid, the engine will stall when you stop.

When you shut it off, pressure bleeds out on the O/D clutch circuit and everything returns to normal. The plunger in the overdrive solenoid might be sticking closed.

I'm pretty knowledgeable with the 42re and WJs up to 2004, but I've never done anything with the WK or WK2. Sometimes my diagnosis sounds like rambling because that's how my mind works. By explaining all the possibilities, something will pop up and the answer becomes more obvious.