95quicksilver

I have a 4.0L Laredo that is giving me transmission error codes 22 and 23. I know that the error codes are for an overdrive error and a torque converter error. I haven't been able to find any information on possible fixes. I replaced the governor solenoid and sensor about 4 months ago and now the Jeep is once again having shifting issues. My wife normally drives the Jeep but I did experience at least one issue with it. I was trying to get up a pretty long and steep hill. When I accelerated to maintain speed, the trans downshifted, held lower gear till about 4000 rpm and then upshifted. All seemed normal, however after upshift it had no power and could hardly pull itself up the hill. Luckily there was a spot I could turn around. Coasted downhill. Got to stop sign and it felt like it was pulling out in third or OD. Manually shifted into second at next stop and it started in first, shifted to second and then I shifted back into drive. By about 4th stoplight/sign it seemed to be shifting normal again. Mechanic seems to think its a mechanical issue with the torque converter. The Jepp has about 177K miles on it.

Could this problem be caused by an external (to transmission) issue either mechanical or electrical? If so, how can I determine?

oddballracing

I've got a 1995 right now with a code 21,22, and 23. from what I'm reading this could be attributed to the TCM or wiring. the one common wire for all three solenoids is the 12V feed from the TCM.

this is pin 1 on the 8-pin connector at the transmission, I'll be checking for 12V on mine tonight to see what my next steps are, might be a good place to start. search for a "42RE TCM pinout" to see what the TCM connector looks like (32 pin double-row connector).

try this document for some more details of the transmission wiring diagram and connector pinout: https://shop.ukrtrans.biz/wp-content...alogs/42RE.pdf

if you're not pulling a code 21, perhaps you have a wire break on the wire going to the TCC/OD solenoid pack downstream of the tee-off for the gov solenoid (possibly damaged during replacement of solenoids), or the TCM itself.

oddballracing

An update from my end:

I hope this method is feasible on your end as it was a quick troubleshooting step for me on my issue. I pulled a TCM from a 1993 ZJ 4.0/42RE at a local Pick-n-Pull before work yesterday, and installed it in my 95 after work last night. While the Jeep was still on stands, I ran the shifter through all positions several times. After that, I turned it off and ran through the ON-OFF-ON-OFF-ON and received only a code 55 (end of codes) through the O/D light.

At this point i put the wheels back on and took it for a short trip up and down the road next to my shop (didn't go too far or over 80km/h as it was midnight and the vehicle is not registered, and several other issues such as broken sway bar link, brake wear, etc. and a loose tailpipe made me want to take it easy). I confirmed that it was taking off in first, shifting decently into second, and then third, and then OD. confirmed first and second gear lockouts worked as expected as well. returned to the shop and ran through the ON-OFF-ON-OFF-ON again, and still only a code 55.

One thing to note here is that the TCM numbers are different between 93 and 95, both from my experience and research in recent days. The unit I pulled out of my 1995 is a 5602 7564 and the unit I pulled from the 1993 is 5602 7218. They look exactly the same (both externally and the PCB itself), same relay part number and such. I can't speak to any long term differences in how they operate, but it was enough for me to pinpoint the module that was putting my unit into limp mode and throwing the codes. I hadn't come across anyone else running this combination, but in theory only programmed shift points may differ: same transmission and engine combo, the differences can't be too significant.

If you can track down a spare TCM at a wrecker, it may be a good step in determining whether this is your issue, or if you may need to dig deeper into wiring, or look at repairing the existing TCM (capacitor and/or relay, connector, etc.). I described this at checkout as a "transmission controller" and was charged at the Pick-n-pull for a "control module" at a total with tax and core of $26CAD. I've never been a big fan of parts-swap diagnostics, but in this case it was easier than pulling the pan and probing wires, and I'm still sore from the recent work on my 98 ZJ.

I'm just getting my head around this transmission and it's controls (never been a big automatic transmission guy, but I'm interested in it much more now), but if I can be of some help here, then i guess that's a good thing.