Jeep Garage  - Jeep Forum banner

1 - 11 of 11 Posts

·
Registered
2002 Jeep Grand Cherokee Laredo 42RE transmission
Joined
·
2 Posts
Discussion Starter #1
I have been all over this Jeep engine light came on when my husband was driving. He pulled into our deer cmp which is on seasonal road and when I looked at Jeep I noticed something hanging on the drivers side rear. The entire emissions system was hanging by one hose. The bracket had pretty much rotted completely out. Most of parts had been dragged and were full of dirt. Took out completely and fabricated new bracket out of stainless then cleaned each piece and put back together. The engine light was on nd I assumed it was because of emissions. Put scanner on to clear.but had transmission codes on it, not emissions? Then husband decided to tell me that it wasn't going into gear unless he let up on gas. Soooooo codes led me to believe it was the [1 - 2] 3 - 4 shift module. It was bad and I replaced. Code still came up the same. I was baffled and sick of having mud in face and eyes. So I called my mechanic who is also my nephew. He has just went legal with his shop but is young. He checked the module just to make sure and played with switching out a couple others out of my other jeep which he has because he is fitting it out with a plow. Same thing. My brother in law teaches auto diagnosis at our Boces and has helped out before but they stopped doing trannys. Both of them told me I would have to go to dealership, they may have just told me to go to the devil. Well we live in the boonies so there was only one place that could do it and it was Bradford PA. I am not fond of dealerships. Nephew wanted me to have it flashed and brother in law wanted it diagnosed. So I told them to do the diagnostics for only 100 dollars, And if it needed to be flashed do it. For an extra 125, they are not cheap. Also told them if work needs to be done I would do it. They said I should wait cause it wouldn't be long. 4 1/2 hours later.....
The idiot hands me an estimate to change the same solenoid that I had told him was just switched. Estimate was for 850. It did take me a whole hour to do it. Mine came with wire they wanted 60 for the one on bill and 250 for the 58 dollar one I bought that came with line. Back I go to Fudds, my nephew, and we tested solenoid they said it read 6 and it definitely tested correctly. So now he thinks may be PCM. But hate to purchase on a hunch. Codes are now both shift solenoid and an odd one. Is there anyway to test PCM?
 

·
Registered
2014 WK2 Overland
Joined
·
816 Posts
You may have better luck in the WJ Jeep Grand Cherokee forum. This forum is for 2011 and above Grand Cherokees.

Quick quesiton: After the shift solenoid replacment(s), did you perform a "relearn" procedure on the transmission via scan tool?
 

·
The beast from Brazil
Joined
·
8,246 Posts
I don't think the 42RE has a relearn function which can be performed.
What are the exact fault codes presented by the PCM?
 

·
Registered
Grand Cherokee
Joined
·
2,822 Posts
I don't know for sure, but I think all electronic transmission have a relearn function, at least all Chrysler transmissions.... ....if its adaptive programming that adjusts with feedback from sensors, how do you re-baseline it after repair?
....They may call it different things, reset, quick learn, etc.... ....but the idea is to clear the memory of all stored correction factors, and have it learn all new correction factors with no early ones to average them with.....
 

·
The beast from Brazil
Joined
·
8,246 Posts
The 42RE transmission is in fact an old fashioned transmission which uses throttle pressure and governor pressure to shift gears. There is not a real electronic control with this transmission. The governor pressure is electrically controlled with a solenoid and the pressure sensor gives the feedback of the actual pressure. The only shift which is controlled electrically with a solenoid is the 3 to 4 shift (overdrive).
 

·
Registered
2014 WK2 Overland
Joined
·
816 Posts
Frango is correct. Having not seen a 42RE in a while, my brain was locked on a RFE transmission which supports component relearn procedures. Sorry for the misinformation!
 

·
Registered
Grand Cherokee
Joined
·
2,822 Posts
That explains the questions about the PCM, the few electronic management items added to the hydraulic based transmissions were controlled by the PCM. Early in another post she spoke of shift solenoids, now she talking about modules, that and the "E" in the designation also lead me to believe it was an electronic trans... ....its like Frango and Ratchet are saying its a hydraulic trans with a few electronic controls added to it controlled by the PCM so it doesn't have a quick learn process...... ....for that they added the "E" to it, but its hydraulic.....

But what that also means, malfunctions and worn out parts in the trans are not going to have codes like electronic transmissions. You may have a few codes for the few items the PCM controls.... ...but you could have completlt worn clutch packs, out of adjustment, etc... ...and since a computer isn't managing the main operation it is not going to set codes for that......

To many Dealers are idiots, they likely left their books on the shelf and just read the codes and made a wild guess based off the trouble codes..... ....that is all they are doing now....

Have you thought about taking it to a transmission shop? I'm just realizing your best course of action is likely to go through the book troubleshooting procedures, which I suspect today, only a transmission shop will do that.....

How many miles are on this vehicle/trans?

In short, don't assume you have bad PCM, you could have a worn out or malfunctioning transmission, and there is no electronic monitoring to set a code for that.... ....I'd stop chasing codes and start doing old fashioned hydraulic transmission troubleshooting....

Another coa might be to find a cheap rebuild or junkyard trans and have your family connection shop replace the trans with another good one..... ....the symptoms you describe sound like the trans is slipping, and that pretty much is the kiss of death for the old hydraulic trans you could count on the diagnosis to be its worn out and needs to be rebuilt.....
 

·
Registered
Joined
·
41 Posts
Have you decided to change the Transducer and the pressure sensor. It sounds like both could be bad. And while your changing those it would not be a bad idea to change the fluid and filter to the transmission being there right below both sensors.
 

·
Registered
Joined
·
4 Posts
I have been all over this Jeep engine light came on when my husband was driving. He pulled into our deer cmp which is on seasonal road and when I looked at Jeep I noticed something hanging on the drivers side rear. The entire emissions system was hanging by one hose. The bracket had pretty much rotted completely out. Most of parts had been dragged and were full of dirt. Took out completely and fabricated new bracket out of stainless then cleaned each piece and put back together. The engine light was on nd I assumed it was because of emissions. Put scanner on to clear.but had transmission codes on it, not emissions? Then husband decided to tell me that it wasn't going into gear unless he let up on gas. Soooooo codes led me to believe it was the [1 - 2] 3 - 4 shift module. It was bad and I replaced. Code still came up the same. I was baffled and sick of having mud in face and eyes. So I called my mechanic who is also my nephew. He has just went legal with his shop but is young. He checked the module just to make sure and played with switching out a couple others out of my other jeep which he has because he is fitting it out with a plow. Same thing. My brother in law teaches auto diagnosis at our Boces and has helped out before but they stopped doing trannys. Both of them told me I would have to go to dealership, they may have just told me to go to the devil. Well we live in the boonies so there was only one place that could do it and it was Bradford PA. I am not fond of dealerships. Nephew wanted me to have it flashed and brother in law wanted it diagnosed. So I told them to do the diagnostics for only 100 dollars, And if it needed to be flashed do it. For an extra 125, they are not cheap. Also told them if work needs to be done I would do it. They said I should wait cause it wouldn't be long. 4 1/2 hours later.....
The idiot hands me an estimate to change the same solenoid that I had told him was just switched. Estimate was for 850. It did take me a whole hour to do it. Mine came with wire they wanted 60 for the one on bill and 250 for the 58 dollar one I bought that came with line. Back I go to Fudds, my nephew, and we tested solenoid they said it read 6 and it definitely tested correctly. So now he thinks may be PCM. But hate to purchase on a hunch. Codes are now both shift solenoid and an odd one. Is there anyway to test PCM?
the bradford dodge garage is a dead end. i had a 1999 cherokee sport that would not stay in OD and the cruise quit working. we swapped out the trans (with a confirmed good one) with now luck. took it to them they did their diagnose and said they didn't know it either needed new trans (1200.00) or new computer, they said one mech. had an idea it wasn't grounding proper so the dummy ran a ground wire from the battery to the bell housing LOL. that switch operates the brake lights, shuts of the cruise when stepping on the pedal, and kicks off the OD when useing the pedal. they charged me 178.00 for this useless crap. come to find out i fixed it be replacing the brake switch on the brake pedal for less than 7.00. (now don't tell me they never had a problem like mine brought to them before and they had now idea how to solve it!)
 

·
Registered
Joined
·
41 Posts
I don’t usually talk bad about dealerships with Bradford dealership is just a joke I don’t even know why they’re still open how they’re still open they tried charging me $1000 one day years ago to do 45 minutes of work I said nope I’m done have a nice day couldn’t tell me what it was and what not just decided to charge me that
 

·
Registered
Joined
·
4 Posts
I don’t usually talk bad about dealerships with Bradford dealership is just a joke I don’t even know why they’re still open how they’re still open they tried charging me $1000 one day years ago to do 45 minutes of work I said nope I’m done have a nice day couldn’t tell me what it was and what not just decided to charge me that
last year i had bought a 2002 grand cherokee which needed a new fuel filter (the fuel regulator is built into the filter- not a smart move) i tried 2 different name brand after market ones that wined and howled badly so figured a dodge one would work LOL at close to 200.00 for that it was just as bad they did replace it but still had the same noise. they refused to replace it a 2nd time and said i needed a new fuel pump which i had replaced before the filter. the last noisy one from dodge is still in the vehicle but has very slowly become quieter for the last year of use, but can still be heard. oh and they said the ones (after market) i had bought were probably made in japan (but they actually were made is the usa. the ones with the dodge name were made in japan.
 
1 - 11 of 11 Posts
Top