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Jeep Grand Cherokee Transmission Problems

1070 messages,  Last post on Jun 17, 2013 at 4:48 PM

You are in the Jeep Cherokee and Jeep Grand Cherokee Forum.

What is this discussion about? Jeep Grand Cherokee, SUV

Messages Page 46 of 108

#445 of 1070 Re: 2001 grand cherokee transmission shifting problem!! [amab] by nneal

Nov 06, 2009 (6:44 pm)

Replying to: amab (Nov 05, 2009 9:05 pm)
My 98 Cherokee with an AW4 transmission had the same symptoms. Not sure what your transmission is. I brought mine to a transmission repair shop for a free first time estimate, and all he could tell me he was the fluid was a little dirty and he didn't know what was wrong. According to him, my only option was a total rebuild. Then I thought, what the heck, I'll bring it to the Jeep dealer, with all their tools they will know what's making it act up. I got the same answer from them, only this time I was a $100 poorer.
 
  I knew the "guts" of the transmission was alright, because like yours, once I got it to drive it ran normally. Only when I came to a stop, it would not shift down to first unless I manually put it there (in order to take off again). So with nothing to loose, I bought a solenoid kit consisting of three solenoids off the web and installed them. To my surprise that's what my problem was.
 
  If this is what you decide to do, look around at some of the transmission parts sites on the web for solenoids. The Jeep dealer wants an outrageous price for theirs. I got all three solenoids (the kit) off the web for LESS than the price of one from the Jeep dealer.

#446 of 1070 Re: Transmission Shifting Problems [nneal] by xelvis66x

Nov 06, 2009 (9:04 pm)

Replying to: nneal (Nov 06, 2009 6:18 pm)
Sounds good to me. I had the scanner hooked up tonight with my brother watching it and everything is working and there's no codes, we cleared them so now I'm going to drive it tomarrow and see what happens. It tells me the readings of all the sensors to do with the tranny, so I want to see if they are correct. Also the scanner says that everything is good and ok to drive.
 
Do you think the TCM could have gone bad. I was reading about them and TCM tells the tranny when the best time to up shift and downshift, but there is only one shift solinod in that tranny which is for the OD and the rest I think is controled by shift valves. and the solinod is working because I have all gears.
 
I need to look at the engine again I ran out of time. I want to check wires to the TPS.
Thank You!

#447 of 1070 Re: Transmission Shifting Problems [xelvis66x] by nneal

Nov 07, 2009 (5:17 am)

Replying to: xelvis66x (Nov 06, 2009 9:04 pm)
From what you've discovered so far, I don't think the TCM is bad. I have a spare one which I used to switch with the factory one to rule out the TCM, and that has never gone bad on me. I've read some people have had the dealer reprogram (or Flash) them, but it's not cheap. Yes, from what I read your TCM controls the solenoid for 3-4 upshifts and back down. Shift valves control the 1-2 and 2-3 upshifts (and back down I assume - they don't say). But what actually controls the shift valves themselves is the TCM, because it controls what the governor pressure solenoid does - and that is how much pressure the shift valves have to work with. So actually, there are two solenoids, one is a shift solenoid (3-4) and the other is a governor pressure solenoid (valve body), from which controls your shifting. The clinker in all this is that your TCM relies heavily on inputs from all your sensors, so they make a good weak point.
 
  One thing I thought of and read somewhere, is make sure the ground strap from the engine (or tranny) to the frame is good, otherwise it will mess up all the electrical parts and make them act strangely. Especially after working with the head, there might have been one connected to it.
 
  You're lucky you've got the tools and a brother who knows what he's doing. Best thing is, don't get discouraged because in the end I'm sure you're going to find it's only a wire or small component that's screwing things up. I've been there many times.

#448 of 1070 Re: Transmission Shifting Problems [nneal] by tuggajb

Nov 07, 2009 (11:41 am)

Replying to: nneal (Nov 07, 2009 5:17 am)
there is a ground strap from the back end of the head that you could have forgot to hook up

#449 of 1070 Re: Transmission Shifting Problems [tuggajb] by xelvis66x

Nov 07, 2009 (6:46 pm)

Replying to: tuggajb (Nov 07, 2009 11:41 am)
There's not one of them on mine but I know what you mean. When my brother work on his cherokee a few weeks ago (headgasket) we had to unhook that strap, but the only thing that is in the back of mine is a plug, I think with one wire and I checked I out and played with it and it didn't change anything. Do you know what that wire is for. It screws in to the head then a plug hooks on?

#450 of 1070 Re: Transmission Shifting Problems [nneal] by xelvis66x

Nov 08, 2009 (5:38 am)

Replying to: nneal (Nov 07, 2009 5:17 am)
There was no ground strap on the back of the head like my brothers, a one wir plug which I had to unhook. This screws down into the head then the plug hooks on from the harness. Could this be my ground to the head.

#451 of 1070 Re: Transmission Shifting Problems [xelvis66x] by nneal

Nov 08, 2009 (8:38 am)

Replying to: xelvis66x (Nov 08, 2009 5:38 am)
Could very well be. Either way, the transmission has to be grounded to the frame in some way for it to work right. A corroded ground would cause the same problems. My Jeep has a flat braided strap (wire) from the head to the firewall. I don't know what 95 models used.

#452 of 1070 RE: Answers & Solutions by nneal

Nov 08, 2009 (9:12 am)

I would like to add a request to all the people posting their vehicle problems in this forum. If you have found what was causing the problem in the message you posted, please let the rest of us know what your solution was so we can all benefit by it. I've learned and discovered many solutions in forums like this not found anywhere else. Many of them are not to be found anywhere, not even from the manufacturer. Forget garages and transmission specialists, as they are not going to throw away easy money. Feedback benefits everybody! Thank you.

#453 of 1070 Re: Transmission Shifting Problems [nneal] by xelvis66x

Nov 08, 2009 (11:40 am)

Replying to: nneal (Nov 08, 2009 8:38 am)
You think oil will make a ground short out because there is oil on some of the plugs and I've been spraying them with WD-40. I'll ave to look and see if there's a ground.

#454 of 1070 Re: Transmission Shifting Problems [xelvis66x] by nneal

Nov 08, 2009 (12:19 pm)

Replying to: xelvis66x (Nov 08, 2009 11:40 am)
I doubt if oil would affect anything, although the cleaner the better. After having driven it some, are you still code free?

Messages Page 46 of 108

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