Last post on Dec 06, 2013 at 12:29 PM
You are in the Jeep Cherokee and Jeep Grand Cherokee
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Jeep Grand Cherokee, SUV
#441 of 1101 2001 grand cherokee transmission shifting problem!!
Nov 05, 2009 (8:05 pm)
Hi , I need help !! my 2001 jeep has 150K on it , and when i take off the car is so heavy like putting a lot of effort ( i assume the transmission starts from the 2nd)
and it will not shift to 3rd or 4th unless i start driving with the shift is on 2 and when i aproch a highway i shift it to D and OD then it runs smoothly , it used to do that once in a while but now it does it everyday , took it to the mechanic he said rebuilt or change the transmission which i will not do and prefer to sell the car instead if couldnt fix the problem , so please Help !!
#442 of 1101 Re: Transmission Shifting Problems [xelvis66x]
Nov 06, 2009 (4:15 am)
If you wiggled the harness and got a trouble code when there was none, it seems like there's a bad connection (or wire). Be careful as I have, of tripping a code by unplugging a sensor or something else.
The 42RE article about the default mode means if the TCM has a trouble code set, then it places the transmission in default mode as you described. On my 98 Cherokee, when I erase trouble codes with the scanner, it erases trouble codes in everything (engine computer and TCM). On my Jeep, I can only read the engine computer trouble codes, and not the TCM. I'm told I need a DRBII scanner to read those which the dealer has and is very expensive. I was surprised by some Jeeps with the 42RE, having the capability to read trouble codes of the TCM separate of the engine computer. I don't know if yours has an overdrive switch, but this is what the article described:
"This system has self-diagnostics. Fault codes can be read with a scan tool or by cycling the ignition key three times, then counting the flashes of the LED in the OD off switch."
Good luck and keep us posted on what you find.
#443 of 1101 Re: Transmission Shifting Problems [nneal]
Nov 06, 2009 (1:46 pm)
Yes I think a wire is bad I haven't checked yet.
My Jeep is a 95, with the OD off switch, which is before the OBD-II scanner connector, mines the OBD-I connector, there is one in the engine bay at the computer which we looked at and some codes were on that we caused, and then I found a plug inside for my TMC. The scanner we have reads the TMC and the computer, from that we got alot of readings, but I had no codes when I had the scanner in. Now with the flashes you said about I checked because I didn't have the scanner and I have TPS codes in both computers, this is after I wiggled the wiring harness a few days ago.
How do you know if it's in default mode, from the articles my symtoms would say but i'm not sure. I guess the scanner will reset this.
#444 of 1101 Re: Transmission Shifting Problems [xelvis66x]
Nov 06, 2009 (5:18 pm)
The way I translate the article (link title), default mode is when you place the transmission in "drive", it automatically goes to third gear. You can make it go to reverse or second gear by manually putting it in that gear yourself. Seems like you have a choice of three gears while in default mode. To me it doesn't sound like you're in default mode because you have all your gears, they're just not shifting right.
#445 of 1101 Re: 2001 grand cherokee transmission shifting problem!! [amab]
Nov 06, 2009 (5:44 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 1101 Re: Transmission Shifting Problems [nneal]
Nov 06, 2009 (8:04 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.
#447 of 1101 Re: Transmission Shifting Problems [xelvis66x]
Nov 07, 2009 (4:17 am)
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 1101 Re: Transmission Shifting Problems [nneal]
Nov 07, 2009 (10:41 am)
there is a ground strap from the back end of the head that you could have forgot to hook up
#449 of 1101 Re: Transmission Shifting Problems [tuggajb]
Nov 07, 2009 (5:46 pm)
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 1101 Re: Transmission Shifting Problems [nneal]
Nov 08, 2009 (4:38 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.