fwlau

Hi all, thank you in advance for any input and help you can provide. I will list the series of events in chronological order to try and condense what could be a potentially very long post.

1. Purchased an automatic 2001 Jeep Grand Cherokee with a 4.0 inline 6 motor and 157K on the odometer. Drove perfectly for two weeks. Had inspection done, transmission fluid was CLEAN.

2. CEL lit up, mechanic says torque converter code, most likely just an electrical relay, cleared code and said to drive and see if the car exhibited any different behavior or the CEL came back.

3. A day later, I'm driving on the highway, O/D turns off by itself, RPMs are at 2500 @ 60mph, CEL lights up.

4. Exit highway, slowing down at red light and engine braking seems very heavy, not very loud clunk when I come to a complete stop (transmission forcing itself into first?)

5. Green light, try to accelerate, revs build but no speed, I fiddle with the gearbox and after a couple of attempts, I get movement in first, pull to gas station, transmission over temperature lights up.

6. Speak with mechanic, he says bring it by ASAP, I'm 68 miles from home. He says disconnect the battery and let sit for a minute to clear everything and then come home. I do just that, all lights disappear, car drives like normal.

7. Ten minutes later, RPM spikes again but this time no lights on the dash, no O/D, CEL, or Trans light at all. Continuing on, suddenly it appeared like the Jeep went into neutral, revs spiked but no acceleration. I pull to the shoulder and sit for half an hour. No odors coming from the Jeep or anything.

8. Start the Jeep up again, no lights come on, hard to get movement, I fiddle around with the gearbox and finally get going in 1st, shift up to 2nd, and then finally to drive. Car seemed very underpowered. I keep the RPMs steady at 2K all the way to his garage.


Now, none of the gears appear to have normal behavior, the car is extremely slow accelerating, and when I brake it is very hard to build speed again, if I can at all. I'm aware of the solenoid and governor sensor issue and that is the first thing we are looking at, but I'm wondering what the chances of a transmission problem are?

As I previously said, when we got the jeep inspected a week prior to this occurring, the transmission fluid was clean, no metal flakes or anything. It seems this problem came out of nowhere. My rational is that it is highly likely that it is just the solenoid and governor because from my experience, electrical issues pop up in an instant but mechanical issues typically occur gradually. Is the fact that I was able to drive the Jeep 60 miles in the underpowered form a good sign?

Will a bad torque converter solenoid cause the car to exhibit behavior similar to that of a bad transmission?

I have a 12 hour drive in ten days and need to get this issue sorted out before that takes place. I really appreciate any input you guys have. Thank you!

dave1123

All the torque converter solenoid does is engage the converter lock-up clutch which decreases the engine rpm by only 10%. I've been driving with a bad one for over a year and the only difference it makes is about 200 rpm at 65 mph and 2 to 3 less mpg.

The governor pressure is critical to controlling shift points. Also, there is a thermister (temperature sensitive resister) that senses transmission temperature and will not allow O/D to work over 260*. You may have a plugged trans cooler that isn't getting rid of the heat and causing the trans to malfunction. I'm afraid you'll have to do a complete transmission diagnostic check to find the cause. Hopefully the problems are electrical and not mechanical.

fwlau

Thanks for the response! I'll relay that to my mechanic when he drops the pan. He did drive the jeep for a bit and was able to replicate the problem, then pulled the dipstick and it didn't smell like any fluid was burning or anything. Tomorrow is pan drop day though as we'll have the new solenoid and governor sensor so we'll be able to know more and at least see if there are any signs of mechanical problems.