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TJ Rubicon Automatic Transmission woes

MigGunslinger

MigGunslinger

Red Skull Member
Joined
May 21, 2020
Member Number
909
Messages
586
Loc
Sacramento
Ok, I am about at my wits end with this thing. Transmission is constantly going into limp mode and I have possibly been in denial that it needs a rebuild, trying everything under the sun and shooting the parts cannon at it. Damn thing is about to look like the one in my avatar and end up in a junkyard. I would really appreciate some help trying to unfuck this Jeep.

06 TJ Rubicon 4.0L
140,000 miles
42RLE transmission

I don't have any pictures from the mall so here is one at the grocery store, This is partial payment for you reading the wall of text below.
IMG_0024.jpg


Moab trip in April 2021. Jeep ran great except would occasionally upshift to 2nd gear while shifter was in 1st in 4-wheel low.

In late May, or Early June I started to notice a hesitation in the shift between 1 &2. This would normally only happen during warm up. No check engine lights would come on with this issue. After searching online a bit it seems like resetting the PCM will sometimes fix this issue, I did so and the shifts immediately improved.

The transmission functioned normally for 4-5 weeks until the 1-2 shift issue came back and continued to get worse eventually throwing P0700 & P0760 trouble codes and forcing the transmission into limp mode stuck in 2nd gear.

After searching the codes and possible fixes I pulled the valve body and replaced the shift solenoid pack with a Mopar part, replacing the transmission filter, new ATF+4. While doing this I installed a new transmission cooler in front of the radiator bypassing the cooler in the radiator. There was maybe a tablespoon of very fine metal debris on the magnet in the transmission pan. The same P0700 & P0760 trouble codes came back along with the limp mode.

I then pulled the valve body again and installed a new Mopar Transmission range/temperature sensor and fitted a transmission pan with a drain plug and a bung for an analog transmission temperature sensor. The same P0700 & P0760 trouble codes came back along with the limp mode.

The last thing I tried was an aftermarket PCM, it seems that the issues I am experiencing are often caused by the PCM in 05-06 models and there are no factory replacements available. The same P0700 & P0760 trouble codes came back along with the limp mode. I reinstalled the factory PCM.

This brings us to today, I suspect that there is mechanical damage or wear somewhere in the transmission or valve body, or something wrong with the wiring harness between the PCM and transmission. I inspected the wiring harness at the PCM and both connectors to the transmission and could not find anything obvious.

I was going to bite the bullet and bring it in to the dealer but they said I needed an appointment and the next available was 2 weeks from now? At this point are there any other possibilities or should I just order up a rebuilt transmission and put it in myself, I have the tools and knowledge I just don't want to lay down a couple of thousand when there was something else to check.
 
MigGunslinger said:
Ok, I am about at my wits end with this thing. Transmission is constantly going into limp mode and I have possibly been in denial that it needs a rebuild, trying everything under the sun and shooting the parts cannon at it. Damn thing is about to look like the one in my avatar and end up in a junkyard. I would really appreciate some help trying to unfuck this Jeep.

06 TJ Rubicon 4.0L
140,000 miles
42RLE transmission

I don't have any pictures from the mall so here is one at the grocery store, This is partial payment for you reading the wall of text below.
IMG_0024.jpg


Moab trip in April 2021. Jeep ran great except would occasionally upshift to 2nd gear while shifter was in 1st in 4-wheel low.

In late May, or Early June I started to notice a hesitation in the shift between 1 &2. This would normally only happen during warm up. No check engine lights would come on with this issue. After searching online a bit it seems like resetting the PCM will sometimes fix this issue, I did so and the shifts immediately improved.

The transmission functioned normally for 4-5 weeks until the 1-2 shift issue came back and continued to get worse eventually throwing P0700 & P0760 trouble codes and forcing the transmission into limp mode stuck in 2nd gear.

After searching the codes and possible fixes I pulled the valve body and replaced the shift solenoid pack with a Mopar part, replacing the transmission filter, new ATF+4. While doing this I installed a new transmission cooler in front of the radiator bypassing the cooler in the radiator. There was maybe a tablespoon of very fine metal debris on the magnet in the transmission pan. The same P0700 & P0760 trouble codes came back along with the limp mode.

I then pulled the valve body again and installed a new Mopar Transmission range/temperature sensor and fitted a transmission pan with a drain plug and a bung for an analog transmission temperature sensor. The same P0700 & P0760 trouble codes came back along with the limp mode.

The last thing I tried was an aftermarket PCM, it seems that the issues I am experiencing are often caused by the PCM in 05-06 models and there are no factory replacements available. The same P0700 & P0760 trouble codes came back along with the limp mode. I reinstalled the factory PCM.

This brings us to today, I suspect that there is mechanical damage or wear somewhere in the transmission or valve body, or something wrong with the wiring harness between the PCM and transmission. I inspected the wiring harness at the PCM and both connectors to the transmission and could not find anything obvious.

I was going to bite the bullet and bring it in to the dealer but they said I needed an appointment and the next available was 2 weeks from now? At this point are there any other possibilities or should I just order up a rebuilt transmission and put it in myself, I have the tools and knowledge I just don't want to lay down a couple of thousand when there was something else to check.
Click to expand...
If replacing the solenoid and internal harness didn't get it, assuming fluid condition is good without debris constantly in the pan, you're looking at a trans. There could be debris caught in the valve body, making a spool valve stick, or a broken spring, but I think something in the 1-2 circuits is worn past serviceability. you can pull the valve body and have a look around and see if anything has physically failed, but unless its obvious, it could be a waste of time.

Also a good time to install an AA Rubicrawler......
 
Cowboy63b said:
If replacing the solenoid and internal harness didn't get it, assuming fluid condition is good without debris constantly in the pan, you're looking at a trans. There could be debris caught in the valve body, making a spool valve stick, or a broken spring, but I think something in the 1-2 circuits is worn past serviceability. you can pull the valve body and have a look around and see if anything has physically failed, but unless its obvious, it could be a waste of time.

Also a good time to install an AA Rubicrawler......
Click to expand...
Thanks for the sanity check, and for reading all of that. I am definitely thinking the same.

I think I knew about the rubicrawler from seeing them on JKs, it never really dawned on me that it would work on a TJ 42RLE.:homer: I wonder how much real world utility that would bring? I am running the 4:1 Rubicon t-case, 4.88s in the axles on 35s and I have never really felt the need for more gearing (Rubicon, Barret Lake, Moab) but maybe I have been relying on the torque converter / 1st gear too much.
 
MigGunslinger said:
Thanks for the sanity check, and for reading all of that. I am definitely thinking the same.

I think I knew about the rubicrawler from seeing them on JKs, it never really dawned on me that it would work on a TJ 42RLE.:homer: I wonder how much real world utility that would bring? I am running the 4:1 Rubicon t-case, 4.88s in the axles on 35s and I have never really felt the need for more gearing (Rubicon, Barret Lake, Moab) but maybe I have been relying on the torque converter / 1st gear too much.
Click to expand...


The TJ 42RLE and JK (2011 IIRC) 42RLE are same=same.

Edit.....here it is. Rubi-Crawler : Rubi-Crawler Auxillary Crawl Box For 42RLE Transmission | Advance Adapters
 
Bebop said:
Time for an AW4 swap ! :)
Click to expand...
Though an objectively better transmission that's a rabbit hole all on it's own.




Looking for remanufactured transmissions these options come up in the forums, if anyone has any input or experience with these companies I would appreciate it:

42RLE Transmission - $2,295 | 5-Year Warranty | Money Back Guarantee

The 42RLE Transmission You Can Count On. Built With The Best, By The Best. 5-Star Rated Nationally Recognized 42RLE Transmission Supplier.
www.bestbuytransmission.com www.bestbuytransmission.com
1895.00 including core and torque converter

www.atsdiesel.com

ATS 42RLE 4WD PERFORMANCE TRANSMISSION FITS 2003-2006 4.0L JEEP

The ATS 42RLE is engineered to hold the power and abuse Jeep owners can throw at it. Substantial increases in clutch pack surface area, line pressure and shift quality provide the reliability Jeep owners demand. 42-RLE Transmission: The 42-RLE transmission that is used in the 2003 to 2012 Jeep...
www.atsdiesel.com www.atsdiesel.com
2137.00 including core and torque converter (There is a long list of improvements and marketing wank but not sure if it is worth the extra cash.)

I also keep hearing Jasper transmissions mentioned but it looks like they sell through dealers only which is a shame because they have a facility in Sacramento which might make shipping / core return easier.
 
Last edited:
Just bring it to a reputable local rebuilder
 
Even though you replaced the PCM if you didn't get one from Mark at wranglerfix.com it could still be busted. Nobody else fixes the PCM. I'd contact him and ask for help first. Most refurbished PCMs are crap. If you want to see if the transmission is bad then take it to a shop that has a scanner that can read the codes. The transmission tracks its own wear and you can read it with the correct tool. P0700 is also just a generic code, the transmission stores codes in it's own control unit and you need a good scan tool to read it. If your PCM is still a dud putting a rebuilt unit in is an expensive mistake.
 
Bebop said:
Just bring it to a reputable local rebuilder
Click to expand...
I did get one reference for a local transmission shop from a friend. I'll call them and see what their deal is. I have a garage full of tools precisely because every single time I have had to bring something to a shop I get fucked over.
pagrey said:
Even though you replaced the PCM if you didn't get one from Mark at wranglerfix.com it could still be busted.
Click to expand...
The PCM was from wranglerfix.
pagrey said:
The transmission tracks its own wear and you can read it with the correct tool.
Click to expand...
This is one of the only cool things about these transmissions, it might be worth taking to the shop just to have them scan that.
 
TrailTamer said:
have you checked the connector per this link?
Click to expand...
Thanks for writing this out and posting.

Yes, I have seen the TSB associated with that connector. As I stated in my OP I did inspect the connectors for damage and corrosion and I suspected that the issue is either the wiring or internal transmission damage.

I am bringing the jeep to a local transmission shop that was recommended to me and I will have them check this wiring as well as the condition and wear of the transmission.
 
TrailTamer said:
Any update?
Click to expand...
Well I took it to a local transmission shop. Told them everything I had done to it. They did a bunch of testing and were not able to find a smoking gun. They were going to price me a remanned jasper transmission figuring internal transmission damage.

Next day they called and said that when they wiggled the transmission connector at the PCM that shit started to go haywire on their scanner. They suspect a break in the wiring between PCM and Trans but they apparently do not get into wiring harness work and the few old timers they knew who would have retired. They only charged me for 1 hour of diagnostic. So while my problem is not fixed, I at least don't feel screwed over at all.

They were not able to check the transmission for wear with the computer because it needs to have been operating correctly for a time before you can get useful data.

Currently I have the Jeep back home. I have pulled back the sheathing and pulled apart the connector in question, again no smoking gun. I was hoping that since wiggling at the PCM caused issues I could find a broken wire but no luck.

I will be stripping out the harness and tracing every wire. The same harness holds all of the engine sensors and engine controls all the way back to the transfer case so it is going to be a bitch to get out but all of the plastic sheathing is heat damaged and crumbling apart so I will clean that all up. My current theory is an issue with the OD solenoid wire since the P0760 is consistent across all attempts to fix. I guess a shitty power feed or ground at the PCM could be it as well.

I bought a pin extractor assortment but I cannot get the pins out of the connector, I really do not want to mongo them so I need to find details.

This is the connector I'm dealing with.

Mopar Connection Repair Kit

connectors.dcctools.com connectors.dcctools.com
 
You should probably start at the PCM connector since that's where they found the problem. You'll probably find it within 1ft of that.
 
arse_sidewards said:
You should probably start at the PCM connector since that's where they found the problem. You'll probably find it within 1ft of that.
Click to expand...


On It! Nothing yet,

The harness goes across the firewall and below the jeep about 1ft away from the plug so in order to get the slack to look at it I may have to pull the harness out. Not there yet but I did pull the plug apart. Found a depin tool that works okish and some instruction online.
IMG_0919.JPG
IMG_0918.JPG


My stepdad offered to let me use his fault finder tool which may help me find a broken wire or even a bad power feed to transmission.

I depinned the 2 wires associated with the OD solenoid control and pressure circuits, again with no smoking gun yet.
 
Look at the pins very closely and do a " pin drag" test. it may be a spread female pin. by wiggling the harness like you said, I'm starting to think the external harness is the issue from a spread/possibly broken pin. i know on ZJ's, the connector at the PCM is a common issue, I didn't think to connect the dots with a wrangler that's a decade newer.
 
From context I take it that a pin drag test would be taking the depinned connector and sliding it on the pcm pins to check for looseness? I actually did that, there was some resistance but I have nothing to compare it too. The connectors seem to have shiny copper or gold plated caps on them, I suppose there could be corrosion inside or the delicate gold could be wallowed out?

I do have a complete mopar connector replacement kit coming and used connectors from eBay cut out of a Dakota so that will give me a baseline.
1629511383818.jpeg
 
MigGunslinger said:
From context I take it that a pin drag test would be taking the depinned connector and sliding it on the pcm pins to check for looseness? I actually did that, there was some resistance but I have nothing to compare it too. The connectors seem to have shiny copper or gold plated caps on them, I suppose there could be corrosion inside or the delicate gold could be wallowed out?

I do have a complete mopar connector replacement kit coming and used connectors from eBay cut out of a Dakota so that will give me a baseline.
1629511383818.jpeg
Click to expand...
If you have some pins to check the female pins, insert a male pin, and you should feel resistance and you pull the pin back out. it'll be metal on metal grabby. but, it shouldn't have a whole lot either.
 
I have been slammed at work the last couple of weeks including last weekend. I did a couple more continuity checks and resistance checks on my suspected bad wire with nothing conclusive. I also performed the recommended drag test on the PCM pins which seemed acceptable compared to the new ones I bought. The next step is to rip out the whole wiring harness.

So I put on my big boy cargo shorts this morning and got to it:


Removing the skid plate and exhaust,
IMG_0936.JPG



Disconnecting all of the engine connectors including taking off the power steering pump to get to the AC compressor Connector :shaking:, I also mongoed the PCV hose and tore the rubber connector in half:homer:

IMG_0935.JPG


Then to the transmission, transfer case, Locker pumps.

And finally the fuel tank which needed to be dropped to disconnect. I did not get any pics of that because of course the tank was full (as is tradition) and now I smell like gas.

Anyways after fighting the long crumbly harness for a while I got it out of the jeep, most of the tape was so brittle if you bent it it would crack like uncooked spaghetti.

+
IMG_0939.JPG


I put it on my bench and started peeling off tape and tracing my most suspected wire when I found this!

IMG_0941.JPG


That is a rub mark and exposed copper on Circuit T60 OD Solenoid Control!!!

I just so happened to get a picture of the area this was in, about 3 feet back from the PCM connector where the harness turns towards the rear of the jeep. The corrugated tube along this whole section was crumbled to dust and oily as well:

IMG_0938.JPG


I cut out a 1/4" of the wire, crimped it back together and sealed with adhesive lined heat shrink, I also repaired another damaged wire which was some sort of sensor ground in the same area.

I stripped off the rest of the tape, cleaned and inspected all of the remaining wires and connectors and now have it ready to wrap with fresh tape and wire protection. I bought some stuff recommended in the wire loom thread but I will have to wait until it comes in.

IMG_0943.JPG


I am pretty exited as this seems like a smoking gun, I will update the thread again when I get it all put back together.

For now, thanks for all of your help, I was ready to throw in a new trans. There is still going to be a shiny new addition if Advanced Adapters ever ships the damn thing.
 
Great news!

I put in a few hours after work almost every day last week and re wrapped and protected the whole harness. Including new TPS wiring because the old wires were cracked and exposed. Here is a pic of the complete harness. The Tesa harness tape was a bit hard to work with, it does not stretch or form so when you wrap it in a spiral there is always a loose side that you wrap with the next spiral, It seems like quality stuff though. For wire protection I used Polyethylene spiral wrap under the tape which was kind of a bear to get on but I wanted to try it over the traditional corrugated plastic split loom or the woven split. Woven solid loom was never really an option as I would have had to depin all of the connectors to run them through.

IMG_0948.JPG



I put the harness back in the Jeep and after a few false starts ( I somehow forgot that I removed the power steering pump before trying to start :homer:) I got it running and immediately took it for a test drive. Everything seemed to work perfectly, all shifts were smooth all through the gears.

It is so weird driving it again, I have been driving our shop hybrid so long now that I forgot all of the squeaks and rattles this thing has.

I still need to put some miles on it before I call it 100% fixed but the trip in to work this morning went perfectly. Thanks again to everybody who chimed in and gave advice. My rubicrawler was supposed to ship on 8-28 and now it is scheduled for 10-4 I may throw up a pic or 2 of that when it comes in.
 
Hell of a task but very satisfying when it works out.

Great job !
 
I had an 06TJ kick my ass.. Was throwing "output speed sensor" errors and going into fuck mode. I had a fucking full plate with taking care of my aging parents and didn't have the time to trouble shoot this bitch the way I wanted. I flipped it over to a local shop; they tossed in a rebuilt tranny but were a little slow to return the bitch. I strongly suspect the "input speed sensor" was the root cause of all my woes. :smokin::smokin:
 
billdacat said:
I had an 06TJ kick my ass.. Was throwing "output speed sensor" errors and going into fuck mode. I had a fucking full plate with taking care of my aging parents and didn't have the time to trouble shoot this bitch the way I wanted. I flipped it over to a local shop; they tossed in a rebuilt tranny but were a little slow to return the bitch. I strongly suspect the "input speed sensor" was the root cause of all my woes. :smokin::smokin:
Click to expand...
I came across mention of issues with those sensors when trying to figure this out. I got very lucky that the shop I brought it to put in a little extra effort and got me pointed in the right direction.

It is funny because it was just luck of the draw that caused my transmission issues, could just as easily been one of those sensors, locker controls, fuel pump, or any other wire in that bundle. I have been wondering if my 1" body lift, 1" motor mount lift, and custom trans crossmember changed things enough that the factory wire harness location caused the body to rub the wires.

That and the heat cooking everything under the hood. I am surprised the PCM does not just shit the bed in protest. I installed a hood louver while the Jeep was just sitting there broken.

hood louver.jpg
 
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