Let's discuss my 42RLE

[VeroDubs]

2006 RHD with 42RLE

Took my Jeep on a very light off-road excursion today in some soft sugar sand. Right after engaging 4-Low I felt a couple weird shifts and then everything seemed normal.

Ran around maybe 20 minutes then pulled out to get back on the road. Went to reverse back a little and reverse engaged but was slipping so bad. You could tell the jeep wanted to move but couldn’t.

Drove it to my shop where I found I only had 1st and 2nd gears. Once there, on flat ground, I verified reverse was definitely engaging and would attempt to move the jeep, but just wasn’t grabbing hard enough and would slip.

So I check fluid level and condition in park on flat ground. Fluid looked clean and level was perfect.

Scanned the jeep and found the following faults.

P0733 Gear ratio error in 3rd.
P0736 Gear ratio error in Reverse.
P1790 Fault immediately after shift.

Cleared faults and found I still had no reverse. Did not attempt to drive any further to see if it would shift in 3rd or 4th after fault clear.

So anyone have some insight on these faults and issues?

If it’s rebuildable, I’m down. Just not sure what path to take for diagnosis.

Or am I going to need to start looking for a replacement?

 

[Jerry Bransford]

Engine was running while you checked the ATF level right? And it was all the way up to the full mark? It's far better for an automatic transmission to be slightly overfilled than to be underfilled by even a small amount.

If its ATF is up to the full mark I'd be suspicious that your PCM is at fault. The factory integrated the transmission control module into the PCM in 2005 and that's when the problems started due to the excessive heat combining them caused. Mark at @Wranglerfix www.wranglerfix.com might have some input on that or questions for you to see if he feels it is or is not PCM related.

The good news is Mark says they have a permanent fix to that problem.

 

[VeroDubs]

Engine was running while you checked the ATF level right? And it was all the way up to the full mark? It's far better for an automatic transmission to be slightly overfilled than to be underfilled by even a small amount.

Yes, running in park. Right at and maybe even slightly over the full mark.

Also, edited. I’m already running Marks PCM so hopefully that’s not the issue.

 

[pagrey]

Sounds like you blew a clutch and it took out either another clutch or clogged stuff up. It can probably be rebuilt, they replace most of that stuff in a full rebuild anyway. A good shop can read the clutch volume index if you really want to double check but it sounds like at least one clutch has failed. Once that happens all the internals get clogged and things go downhill fast as far as normal operation. It's almost certainly not the control module, it can't tell reverse to slip, that clutch doesn't feather or ever use partial engagement. If you want to rebuild it then stop driving it and have it towed or pull the transmission, if you are just using it as a core it doesn't matter. If you pull the pan you'll probably find a big mess.

 

[hear]

If it’s rebuildable, I’m down. Just not sure what path to take for diagnosis.

It's always rebuildable. I mean, they built it in the first place, no reason to think it couldn't be done a second time. Just start a thread on it, I've never seen a 42RLE up close before.

 

[pagrey]

I've never seen a 42RLE up close before.

This series has more than you'd ever want know. It's the newer variable pressure version from a JK but essentially the same thing. If you just want to see the guts this single video is pretty good. I haven't looked in years but it looks like somebody finally posted at least part of a tear down on a TJ version.

(just watched the last video I linked to, it's funny, that's the guy I want doing my transmission when it blows up)

 

[Mrholland]

I've had 2 of my 3 rebuilt. One of em reverse went out, I continued to drive it for some time with no issue.

Find ya a good mopar transmission guy, he'll make short work of it.