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headusher 10-28-2013 02:11 PM

02' GC Overland Tranny Problem
Just had 90k mile tranny service 2 wks ago by qualified tranny shop at the 93k mark. Old fluid looked good, not burnt, no shavings. Replaced filters, fluid, gasket. Drove approx 300 miles with no problems after the service. Parked the GC for a few days and then felt a little tranny slippage problem. After the tranny warmed up no more slipping. Parked it again for another 24 hours and when I used it again the GC would not move in any gear. Let it sit & warm up for 15 minutes- still nothing. Was told to unhook the battery for 10 minutes and see what happens. Did that a few days later. The GC moved but was slipping badly in each gear (3-4 seconds) before engaging but it moved and the trans problem indicator light came on and is still on. Trans fluid is perfect color & is at correct level & a little above the full mark. Some techs I know don't believe it's the trans. They believe it's a computer problem. They indicated that the trans should not be bad at this mileage. I don't want to take it to a shop that automatically removes & rebuilds the trans without checking for electrical problems if this is the case.

Was told to check the fluid level in neutral so I let the engine get up to temperature and checked it. Still full but the fluid and tranny housing did not heat up and was still cold. Not sure if that means anything.

I was able to get a universal scanner but it displayed 'No Code'. I was told that type of scanned won't work. Suggestions on what may be going on??? Other comments??

Frango100 10-28-2013 04:25 PM

Re: 02' GC Overland Tranny Problem
Just to be sure, the text says 02 GC overland, but the information above says 4.0L.
Don't think that they made overlands with 4.0L and 42RE transmissions, so i presume you have the 4.7 with 5-45RFE.
You say that the transmission problem indicator light came on, but there is no such light. You can have the "transmission overheat" indicator light, or the "check engine" light. Normally when there is a transmission problem, the "check engine" light comes on and a code P0700 is set. This code only tells you that the TCM (transmission control module) has set a fault code and that you have to take the jeep to a place where they can read the TCM faults.
The universal scanner didn't show anything, but did you try the key dance? Ignition switch off/run three times and leave in run at the third time. Odometer will show DONE or any fault code, but not the TCM faults. It should show the P0700 though.
Where previous fluid changes done in time? No transmission flush performed?
Fresh fluid has strong cleaning properties and can remove dirt, which can block orifices and cause problems.
The first thing i was thinking about was a detached inlet filter, but that would cause no movement at all, all times. Did you check the fluid after running for some minutes to check for air bubbles on the dipstick?

headusher 10-28-2013 05:26 PM

Re: 02' GC Overland Tranny Problem
Yep-typo it's a 4.7. Did the key thing and got no codes but the indicator light blinked about 10 times and stayed on. You are right it's a MIL not a trans malfunction light. Don't see any bubbles on the dip stick. No flush and it had a 60k the 90 k service. I bought the GC with 41k on it so not sure about previous services but was told both times no problems were detected each time and the same tech did both. Was able to move the car today after revving the engine for 30 seconds so this is another wrinkle in this story. Yes there was slippage but not not as bad as it has been.

Frango100 10-28-2013 07:19 PM

Re: 02' GC Overland Tranny Problem
In reverse no electronics are used for switching, its a mechanical valve in the valve body which does this. If it also didn't move in reverse, then the problem could be a too low line pressure (could be a sensor problem, or the pressure regulation solenoid on the solenoid pack or the pump/mechanical regulator)
When it happens again, i would remove the transmission control relay in the PDC. Then all power will be removed from the tranny and it will go into limp mode. See if it then moves. It will be in 3rd gear only with the shift lever in D, or in 2nd gear with the shift lever in manual 1 or 2. You could also remove the line pressure sensor connector (on the right hand side of the tranny, close to the exhaust hanger), then the line pressure will be regulated to a fixed value and this will override a faulty line pressure sensor. (for this the transmission control relay should be in place again)
Could be torque converter related, but don't see the relation to this with the service performed.
But first find a place where they can read the TCM fault, then we can see for further action.
Edit: the check engine light shows that there should be some fault detected. Did the keydance show "Done"? The PCM should at least have stored the P0700 fault code. You could go to autozone or alike to have them scan the TCM.

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