Ok, so hear goes the story, its a little long so bear with me please. We have a 2002 GCL with 98,000 miles on it. It has the 42re tranny I6 4.0. Tranny was slipping, so did a fluid and filter change. still shifting prob. Soo we changed speed sensor. Was okay for a few days, then tranny acted up again. At the advice of some good friends, took it to tranny shop..>never again< Got it back a week later and $550 less with them saying that a rebuild was in order. Well, since i was not convinced that was the problem, I came to the forum and did some research and found that it was the governor pressure sensor and selonoid. Replaced both and adjusted the bands, took for a test drive. Shifted perfectly.About 30 minutes later, the trans over temp light comes on! I am wondering what the blue blazes they did to my tranny at that shop?!?! We are going to check the tranny coolant lines tomorrow, but was hoping someone might have some insight as to what else to look at. The fluid level is fine and there is no discoloration to it and it doesnt smell burnt. There are no leaks at all. Is ther a way to check the sensor and selonoid to make sure they were not faulty without taking them all the way out first? Is there another sensor that we need to get? And there are no codes. Called dealership and they said for $80 they MIGHT be able to tell me the problem. Well, i would rather come here first. Thanks in advance for all your help.
that is a brand new part your thinking maybe its faulty? Anyway to check that without dropping the pan? Anything else that would cause the tranny to overheat? I read that if its overfilled just a little bit that would cause problems. Hubby is getting frustrated but I love my jeep and really want to solve this if we can. i am not ready to throw in the towel just yet, just need some other ideas on what to look at. Maybe the band are to tight? anyway to check on those as well? Anyway to check the coolant lines for pressure? Any ideas we are willing to try.
Yes to be honest I suspect that part. Unless you sense hard or delayed shifts I would not suspect the bands.
I would check the pan temp after you've gone for a nice and long cruise, btw does it go into 4th with OD on? Anything above 250 would indicate a mechanical issue. If it is not overheating then this would further lead me to believe that the new part is suspect.
If indeed it is overheating the fluid...
You can check if the cooler is plugged by disconnecting the return line from the radiator (if you have ext cooler this will be the line going to that ext cooler) and starting it up. Ensure full flow. If you have a an ext cooler you can also check for flow doing the same but doubt any problems with that unless you where towing something heavy.
The pan will have to come off, I would use a carb/brake cleaner and clean the outside of the pan and catch the fluid in a clean container for reuse (shame to waste it). Prefilter with cloth if you get any dirt in there in the process.
when we test drove it it shifted fine into all the gears...we went to get off e-way and trans over temp light came back on, then O/D kicked off...I dont have a trans temp gauge to tell me the actual temp of the fluid. We thought we could hear it getting hot, like simmering under the gear shifter... leading us to believe that maybe the coolant line is clogged somehow. Hubby wants to replace the trans coolant lines anyways, so we are hoping that is the cause. Anyway to check that new sensor? Maybe a volt ohmmeter? And since there are no codes...i am further thinking the coolant lines.
if the origional govenor was contaminated with debris it makes sense that the same debris is in the cooler possibly restricting it
overheating engine will overheat the trans as well
corroded wires going to the temp sensor can change the reading as well
I just had my transmission replaced due to a TCC code (Torque Converter Clutch). The diagnostic system recorded slippage in the TCC (Code P0740 I believe). The transmission made noise when I got up to about 45-50 mph. Mechanic said the whole transmission was damaged because of the ruined torque converter clutch. I've done alot of reading on the subject and one thing I learned is that if the clutch is in fact slipping, this alone can cause the trans to overheat. The added friction of the slippage is the cause. Not to say you shouldn't keep troubleshooting the Torque converter but you may further damage your transmission if it's not damaged already if you continue to drive it. Just a shot in the dark but maybe you need a new torque converter.