Need an advice on my 2004 42RLE mini overhaul

[TexasTJ2004]

Hi Folks,
I am having some issues with my 2004 42RLE with 105K miles. Have to notice that in last 6 months I was having issues with engine running hot (root caused to be bad water pump). ATF+4 level is really just a little bit overfilled (half quart maybe).

I have multiple issues with it:
1. When it is hot mainly, sometimes it does not engage in Reverse. Like I am switching to reverse from drive, and it behaves like it is completely in Neutral. No noise from Shift Solenoids, nothing. Like the shift position sensor didnt pick up that it is supposed to be in Reverse. Does not light the check engine light and does not throw any codes. Never had any problem shifting into Drive, Park, Neutral, 1 or 2. Only into reverse, mainly when shifting from Drive. If i would hear shifting solenoids but somehow it would just slip, I would blame anything other than the shift position sensor, but it seems like the computer simply does not pick it up that it is supposed to be in reverse. Shifting to park or neutral and bringing it back to Reverse always solves the problem. Shifter linkage cable seems completely fine.
2. When it is really hot day after very lengthy fast driving (like 80MPH on highway), sometimes it slips when accelerating from red light to a hill.
3. The shifts are strange and slow, much worse when it is hot.
4. Once in a while it suddenly clunks, with feeling of knock, happens when driving on 45MPH plus, like it pulls the vehicle back. Feels like it doing some kind of wierd shifting.
5. Fluid is much darker than a new one. Was not that dark by far a year ago.
6. When I trying to reverse Up a Steep Hill, there is a shudder like the entire rig is vibrating and like transmissions is going crazy. Feels much less after regearing (4.56 gears with 31x10.5 inch Goodrich tires), was much worse before regearing.

I am planning to do the following:
1. Install the Derale cooler from Jerry's post - in process.
2. Install GlowShift transmission temperature gauge - in process.
3. Replace filter inside transmission - already got Mopar original filter - Hope that i don't find there any chunks of metal.
4. Install external transmission filter - https://www.amazon.com/dp/B000CJ25PC/?tag=wranglerorg-20. Not a must, but I just want to do it. I saw some folks installing one.
5. Drop Valve body. Clean and replace whatever needs replacement. Planning to do it myself, watched the youtube videos and read the FSM and think that I can handle it myself, w/o paying a shop. It is not my daily driver, and I dont mind it staying inside garage for some time. Try not to use any external shops as a matter of old school principles.
6. Might take it to external transsmission shop to relearn clutch volume indexes, although the above listed does not change anything clutch index volume wise. I saw an old post from Jerry where he mentioned that he didnt have to relearn the CVI after the Valve Body area work.

I need your advice on the valve body parts, that I need to deal with when I am dropping it:
- The Solenoid Pack itself. Is it the right part? Should I take something else? - https://www.moparpartsdepot.com/oem...sZXImeT0yMDA0JnQ9c3BvcnQmZT00LTBsLWw2LWdhcw==
- Manual Valve Lever Sensor (supposedly this is also a temperature sensor with a thermistor that reports to TCM the ATF+4 temperature) - I suspect that this is the guy that is not detecting that it is supposed to be in reverse sometimes - https://www.moparpartsdepot.com/oem...sZXImeT0yMDA0JnQ9c3BvcnQmZT00LTBsLWw2LWdhcw==
- TransGo Shift kit for Non-VLP transmissions - https://www.amazon.com/dp/B009SOVRGU/?tag=wranglerorg-20
- Transmission Oil Pressure Sensor - I understand that our non-VLP 42rle does not have a pressure sensor, it is for JKs only.
- Input and output speed sensors - I can replace these easily, they are mounted externally, but I don't know whether it is really necessary.
- Replace whatever seals needed.

is there anything else that I should be looking into? Any advice from the wise? Want to do everything I can before deciding to replace the entire transmission. I kind of expect the internals (clutches, suns, Torque Converter) to be in a good shape at 105K miles.

 

[LONGJP2]

is there anything else that I should be looking into? Any advice from the wise? Want to do everything I can before deciding to replace the entire transmission. I kind of expect the internals (clutches, suns, Torque Converter) to be in a good shape at 105K miles.

Higher than normal RPM and/or getting hot could be the torque converter.
Although, I would think you would be getting a 7** code.
Mine was acting up and I went ahead and had the whole thing rebuilt.

As far as the reverse thing.
I don't think mine ever didn't go in gear, but I do notice that I don't feel any indication that it's in gear till I hit the gas.

 

[Jerry Bransford]

How did you check the ATF level? Was the engine running while you were using the dipstick to check its level? Is it all the way up to its hot full mark while the engine is running?

 

[TexasTJ2004]

How did you check the ATF level? Was the engine running while you were using the dipstick to check its level? Is it all the way up to its hot full mark while the engine is running?

On a hot day, after an hour of driving, stopped on flat at a gas station and checked multiple times. It was little out of hot (two holes of hot, not between them, but quarter inch after them, little overfilled).

 

[TexasTJ2004]

Higher than normal RPM and/or getting hot could be the torque converter.
Although, I would think you would be getting a 7** code.
Mine was acting up and I went ahead and had the whole thing rebuilt.

As far as the reverse thing.
I don't think mine ever didn't go in gear, but I do notice that I don't feel any indication that it's in gear till I hit the gas.

One time I got this

 

[TexasTJ2004]

Also, before I pull the trigger on the rebuild, I want to do some valve body work to check whether it fixes the problem.
Process wise,
Step #1 - I verify with transmission cooler and gauge that it does not go beyond 180F, with new filer and new ATF+4 (use Mopar ones for both). It could be that the transmission is simply overheating and everything else (other than the reverse problem that easily happens when cold as well, although less frequently) is a result of it.
If it is still acting up:
Step #2 - rebuild and cleaning of the valve body and everything. If it is still acting up after it, I will have to replace it with something remanufactured, as I am giving up on suns and clutches and stuff.

My hope is that after rebuild of the valve body and transgo kit, it will work fine

 

[Jerry Bransford]

On a hot day, after an hour of driving, stopped on flat at a gas station and checked multiple times. It was little out of hot (two holes of hot, not between them, but quarter inch after them, little overfilled).

You didn't answer my questions how you checked the ATF level. Engine running or not? The engine MUST be running while the ATF level is checked with the dipstick or it'll show a significantly higher level on the dipstick than is is really there. Low ATF will cause major shifting issues.

 

[TexasTJ2004]

You didn't answer my questions how you checked the ATF level. Engine running or not? The engine MUST be running while the ATF level is checked with the dipstick or it'll show a significantly higher level on the dipstick than is is really there. Low ATF will cause major shifting issues.

My bad, I thought that I have stated it, and it appears that I didn’t. Yes, the engine running, gearbox in neutral (tried park as well, got the same results).

 

[Jerry Bransford]

Thank you, you did it correctly. Park and Neutral work equally well with the 42RLE for checking its ATF level.

 

[hear]

Nobody ever seems to mention it, and after rebuilding my 32rh over the summer I also ignored it, but there's a whole big section in the FSM about how to do various pressure tests. Some require the tires to spin so you'd have to be under it while it's jacked up & running, so maybe that's less than ideal (or can you just remove both driveshafts/put the t-case in neutral?). But there are some pressure tests you can do once you remove the valve body, which it sounds like you're planning to do.

As far as your specific problem, I like to think about it in terms of what components are engaged in various gears. Sometimes you can build a mental Venn diagram based on what is/isn't working and maybe isolate the issue. This matrix is right out of the FSM. For your case, it seems like coming out of P or N, the reverse clutch isn't being applied (or just doesn't work). But if you put it into D and then into R you're saying it does work, so there must be something about the pressure flow once the Underdrive clutch is applied that allows the Reverse clutch to work. As an absolute idiot layperson, I would expect you've got some sort of valve problem that allows it to work from one direction but not from the other.

But you've also talked about other weird intermittent problems, so who even knows. Overhauling the VB isn't hard at all, just keep track of all the parts. There will be tons, and you may find that the FSMs assembly pictures are wrong when you go to put them back together. I filmed myself doing it, and I found myself going back to my youtubes just to see what it looked like at disassembly.

I have that same temp gauge, it works great. Good time to install a deep pan, and get yourself a lube locker gasket. If your transmission work goes anything like mine, you'll drain the thing several times along the way and you won't want to mess with RTV or a single-use gasket or whatever comes with the 42RLE.


Lastly, props for not wanting to take it to a shop. Rebuilding these things, if that's what it comes down to for you, is not very hard. Much much easier than you'd think for this amazing black box of engineering.

 

[TexasTJ2004]

I read about the pressure tests in FSM, found the taps on the transmission. They are not hard to access if front driveshaft is removed, which I plan to do anyway when I will work on valve body (and replace u-joints in it as well, since they are original ones).
I thought about making it in this way. Connect 300PSI pressure gauge to each one of taps, when the Jeep is on 4 jacks, so I can actually perform the transmission operation with all relevant ranges of operation including highway speeds. I have e-locker in my rear Dana 44, so I can run any speeds in the air w/o risking messing up the spider gears (can happen while both tires are in the air, if it is not locked).
However, most of my issues are intermittent, so I don’t know what exactly I will catch with it.

I have lube locker gasket ready, will go in the moment that I drop the pan.

The reason I don’t want to take this to shop is that this is my hobby. I should be able to accomplish work on valve body myself.
So far I have replaced myself the thermostat, water pump, fan clutch, IAC, radiator, ac evaporator, Dana 30 LP with Dana 30 HP, Dana 35 with Dana 44, Dana 44 bearings and seals, converted Dana 44 to disk brakes, replaced master cylinder, almost all brake lines and the list is ongoing. I won’t be scared by some valve body or jiggle inside of it.

 

[TexasTJ2004]

Nobody ever seems to mention it, and after rebuilding my 32rh over the summer I also ignored it, but there's a whole big section in the FSM about how to do various pressure tests. Some require the tires to spin so you'd have to be under it while it's jacked up & running, so maybe that's less than ideal (or can you just remove both driveshafts/put the t-case in neutral?). But there are some pressure tests you can do once you remove the valve body, which it sounds like you're planning to do.

As far as your specific problem, I like to think about it in terms of what components are engaged in various gears. Sometimes you can build a mental Venn diagram based on what is/isn't working and maybe isolate the issue. This matrix is right out of the FSM. For your case, it seems like coming out of P or N, the reverse clutch isn't being applied (or just doesn't work). But if you put it into D and then into R you're saying it does work, so there must be something about the pressure flow once the Underdrive clutch is applied that allows the Reverse clutch to work. As an absolute idiot layperson, I would expect you've got some sort of valve problem that allows it to work from one direction but not from the other.


View attachment 371608

But you've also talked about other weird intermittent problems, so who even knows. Overhauling the VB isn't hard at all, just keep track of all the parts. There will be tons, and you may find that the FSMs assembly pictures are wrong when you go to put them back together. I filmed myself doing it, and I found myself going back to my youtubes just to see what it looked like at disassembly.

I have that same temp gauge, it works great. Good time to install a deep pan, and get yourself a lube locker gasket. If your transmission work goes anything like mine, you'll drain the thing several times along the way and you won't want to mess with RTV or a single-use gasket or whatever comes with the 42RLE.


Lastly, props for not wanting to take it to a shop. Rebuilding these things, if that's what it comes down to for you, is not very hard. Much much easier than you'd think for this amazing black box of engineering.

And BTW, where does your gauge measure the temperature? Is the probe in the oil pan or you plugged it somewhere in the lines as a tap?

 

[Jerry Bransford]

It's always best when the ATF temperature is measured in the pan.

 

[hear]

And BTW, where does your gauge measure the temperature? Is the probe in the oil pan or you plugged it somewhere in the lines as a tap?

I was extremely tempted to put the temp sensor inline, or even put one on the send & one on the return and then wire a switch to show me just how much cooling I was getting...... but in the end I welded a bung into a deep pan and mounted the sender there.

 

[TexasTJ2004]

I was extremely tempted to put the temp sensor inline, or even put one on the send & one on the return and then wire a switch to show me just how much cooling I was getting...... but in the end I welded a bung into a deep pan and mounted the sender there.

Did the sensor interfere with the skid plate? I have a dorman pan with drain plug ready to go in, but my concern is that it will interfere with the factory skid plate

 

[Jerry Bransford]

Did the sensor interfere with the skid plate? I have a dorman pan with drain plug ready to go in, but my concern is that it will interfere with the factory skid plate

It won't.

 

[hear]

Did the sensor interfere with the skid plate? I have a dorman pan with drain plug ready to go in, but my concern is that it will interfere with the factory skid plate

I'm much more concerned that the wires are going to contact the front driveshaft, so I make a point to zip tie them up out of the way.

 

[TexasTJ2004]

Finally finished my Derale transmission cooler.
Will drive and see whether by keeping the temperature at 180F max it will improve the behavior of the transmission.

 

[TexasTJ2004]

Spent 2 hours trying to get the transmission skid off.
Both nurserts were spinning inside the frame.
Such a pain.

 

[TexasTJ2004]

Finally got out my transmission filter.
It looks really dirty. The pan itself did not have any single piece of metal, only dirt. Had some stuff on a magnet, but was not too much in my opinion. Seems like expected. The original filter seems very old.