Blueoriontiger

Hi forum,

First, Jeep specs. 2003 Grand Cherokee Laredo 6-cylinder. As far as I can tell, I have the 42RE transmission, 2WD.

Got a 2003 Jeep Grand Cherokee used from someone last October. It was a bit of a wreck and had to do a lot of work engine-wise, but finally got it running normally.

It had a small snag in which it would hesitate to go into 3rd gear out of 2nd, but it wouldn't do this often, only occasionally. As time went on it would happen more often, and the transmission would feel like it would want to slip out of overdrive (like the gear ratio was too low when you gave it gas and it didn't have power to push the Jeep in such a high gear).

Come February, the Jeep disengaged out of gear while driving down a highway at 55 mph one afternoon. I had to pull over; tried to shift, would not engage into gear whatsoever. It had to get towed back home.

First thing I did was change the transmission oil filter. The oil in the pan was jet black and gritty. Couldn't really tell if it was burnt or not but it looks like it was never changed. I also emptied 7.5 quarts out of the pan. I put the new filter in, added 5 quarts per the auto store's recommendation, then one more later when the dipstick showed it was low (so a total of 6). Fluid I put in was ATF + 4. The Jeep was able to shift, go into gear and drive.

After 30 miles roughly it would stutter and want to stall in 1st gear. I nearly had the Jeep just come to a halt in the middle of an intersection while slowing down trying to turn. When it would get into 3rd gear it would seem that it was fine, and the fluid level was acceptable.

Pulled the pan off again. Drained 5 quarts of oil from the pan. The oil was brown and the magnet I can cleaned the first time around was gunked up again (no large fragments, thankfully). Filter didn't look really dirty but I changed just in case to be on the safe side.

This time I tried to look into everything. Got a code from the Jeep about the HVAC system (0422) via OBD, but nothing with the ignition on/off method, but that was it and nothing else. The fluid on the dipstick was a maroon color now, having refilled with 5 quarts. Nothing was leaking. Drove the Jeep, worked fantastic for another 30ish miles.

Now it almost constantly does not want to shift into second or third gear as if it is stuck. I have to pull over, put it in neutral, then start driving again for it to shift remotely normal. Every time I slow down and the transmission has to downshift, it does not want to upshift into third gear unless I really hammer the gas (and reach about 45mph).

Sometimes if I just start the vehicle up from it sitting a few days, it'll shift very smoothly and without an issue like nothing was wrong, but as soon as I slow down to go around a curve or come to a halt at a stop sign (whatever causes it to downshift to a lower gear), then pull off, it will start revving and not wanting to go into 2nd/gear. Again, the only solution on the fly is to come to a complete stop, shift into neutral then drive again.

The vehicle will engage into whatever gear it is shifted into with the gearshift without any issues since the first oil change. Reverse causes the Jeep to lurch a little bit "harder" instead of a smooth shift, but nothing out of the ordinary otherwise.

I am aware of the bands and am seeing how I can adjust with the tools I have on hand. My gut tells me that it may not be the issue but I'm at wits end short of selling the Jeep or getting a junkyard transmission. Problematic is an understatement. I'm not much of a mechanic but know how to do easy to moderate repairs short of engine disassembly.

My two questions:

1. Any ideas what may be wrong?
2. I drained 7.5 quarts of fluid from the pan initially. Should I put the 7.5 quarts in, or keep running it on 5? The vehicle had been sitting approximately 4-5 weeks since towing and me changing the oil the first time. Is it that it could've been overfilled by the previous owner, or the extra oil from the torque converter leeched out into the pan from sitting such a long time (and perhaps causing these issues?)

I also ask this as every Google search is divided on the answer (half say keep it to factory specs, the other half say put in what you drain out).

Thanks for your time and input.

Cherryokee

IMO, you need a full reverse-flush removal and replacement of transmission fluid. Consider all the contamination that distributed throughout the torque converter, pump, valve body, lines and cooler that still is not blown-out yet. This should dictate a full 10 quart flush and fill. Any one of a number of things may be getting clogged or stuck by random deposits finding there way into the flow every time you get it going again. Band adjustments and stuff like that can follow, once you know you're past the issue causing the shifting hiccups. I'm not sure but you may want to check into the presence of a second filter at the inlet coming from the trans cooler. I know my 45RFE has one but I'm not too sure about your 42RE. Good Luck.

dave1123

There is no reason you can't ADD a return line filter to the trans cooling lines. When I rebuilt my GM 700R4, there was metal throughout the whole transmission, so I added an AC metal can fuel filter in the return line and changed it twice in the first 1000 miles to be sure everything was clean.

The trans holds about 11 quarts of fluid, but the pan only holds 4 quarts. If it takes a long time to change the filter, more can leak out. However many it takes to fill it up to the "full" mark on the stick is what it needs. Be sure to check it in neutral, not park. Just one quart low can make it shift whonky.

You can pull the governor solenoid and clean the screen on it as well as the ports on the overdrive and lock-up solenoids. That might help it also.

Blueoriontiger

Thanks for the reply guys, and sorry for the delay in response.

Just flushed the transmission out today, took about 10 quarts of fluid till bright red fluid came out. Fluid had a good level, took it for a test drive.

It now refuses to shift into anything above second gear. Now it even doesn't want to shift out of first gear if you come to a stop and you're still in drive (which I then shift manually into second to get it to shift).

I did look for a second filter, but there is none. Cherryokee, I do know exactly what you're talking about on your transmission and tried to find it anywhere else along the line, but there isn't any. In the actual transmission there's just an aluminum stub where the second filter would've gone.

Not sure where to proceed next. Guess I'll try dave1123's advice and now try to get out the governor solenoid/ports to clean it out.

wingless

Welcome to the forum.

The ATSG 42RE Manual is an excellent document that could be useful for the diagnostics / repair.

Blueoriontiger

Hi Wingless,

Thanks for the suggestion. As stated in my first post, I'm not too much of a mechanic, so if there's anything complex or super-detailed to diagnose like rebuilding the transmission, I'm probably going to take it to a mechanic to have it looked at/done.

I'm going to see if Pull-A-Part of a junkyard has solenoids, a valve body or with luck even an entire 42RE transmission that I can just pay someone to place into there for me. Will keep you updated if anything else progresses. Thanks again for all the help so far.

Blueoriontiger

Hi everyone, quick update. After some digging around and having a mechanic looking at it, there is something minor with a solenoid that is malfunctioning but not throwing an error code; however this is minor.

The main cause of the symptoms post-flush was due to the kickdown cable improperly adjusted. It would seem the old owners had made it shift hard and rev high to compensate for the clogged transmission; now that it was clean, it was just revving like crazy. I recalibrated and while a bit clunky from the minor issue, drives much more normally that I can use the vehicle once again.

So for now, case closed. Thanks for the advice, everyone.