ybfcsqs1

I have a '94 LAREDO with multiple issues. Xmission shows O/D light when weather is warm. It down shifts gaining 600 revs and randomly has shifting issues from 1st to 2nd. It pops in and out of O/D randomly. 120,000 mi.

wingless

Which engine / transmission?

When was the last fluid / filter change?

How does the fluid look / smell?

Welcome to the forum.

ybfcsqs1

Hey Wingless, tried to post you a reply but got kicked out with a not logged in from admin?? My Jeep is a 1994 GrandCheriokee Laredo with 120k on it. 2WD/4WD SELECTABLE xfer, serviced at 70,000/75,000, fluid looks good, no smell. 4.0 six, don't know the tranny code(42/44 etc). The problem seems to be load related. No load; shifts good if I feather the throttle after warm-up. At speed on the interstate; shifts in and out of 3rd and 4th if going up grade. On top of the hill or down slope; shifts right into top gear and operates normally (no load?). Revs run between 1900 and 2600 when she's mis-behaveing. This is at 60 to 70 mph. Possibly TPS or manifold pressure switch, I don't know. I'm not even sure this is a transmission problem!
Baffled in B'HAM (Jim)

wingless

The 1994 ZJ w/ a 4.0L engine has the 42RE transmission.

The transmission could / should be diagnosed while intact before draining fluids.

Use either the FSM or the ATSG manual to analyze, identify and resolve the transmission problems.

There are pressure test points on the exterior of the transmission to connect high pressure gauges while putting the transmission into different modes. There are internal fluid ports that are tested after disassembly using compressed air.

There are common problems with the electronics failing on those transmission that are fixed by swapping parts.

It sounds like a transmission problem.

FWIW, here is my 46RH Rebuild Topic.

Start w/ all the external stuff, like verification of proper cable and band settings, also fluid level.

ybfcsqs1

Hey Wingless,
Thanks so much for your input. Here are observations to-date. GUESS which DUMMY didn't check his fluid level. Noticed that characteristics seem to be the same as lack of tranny fluid. Never had been an issue before, always right on target at each oil change. Somehow I blew this one. Dipstick barely touched fluid. At a service station/conviniece store, purchased what they had. ATF DEXRON III, 1 quart brought up the level to almost on the mark. Man what a difference. Knew I was in the money at manual gear selection. Then drove it and had no real complaints, just a slight hesitation from 1st to 2nd. Upshifts and downshifts with authority. The amber led associated with the O/D only comes on every once in a while (60 deg. ambient temp). Stays on for a reasonable time then goes out. I can live with this and the moderate rpm gain because I think this is a fluid temp cooling strategy incorporated into the design(you can correct me on this if I'm wrong). About a couple or so years ago I began to see small splotches on the exterior of the Jeep (mine is factory red). I thought this was road grime, never have seen fluid on the surface underneath the vehicle. I now believe this was residue from from the tranny. I'll continue to monitor my fluid level and keep you informed if it seems to be excessive. I now have a new motto; Check the fluid level idiot.

wingless

Glad to help!

Clean the bottom, especially the hoses, bell housing, coolers and all joints. They should stay clean. The transmission does not consume fluid, except through leaks.

The leaks will be visible from the exterior. The amount and location will indicate the problem.

The correct fluid is ATF+4.

A fluid change could help. Dropping the pan would reveal the amount of contamination sitting in the bottom. It would also permit adjusting the band.

dave1123

JMHO, but stick with wingless, he seems to know what he's talking about.

ybfcsqs1

Got kicked of my "reply' again?? Would like to know Wingless, if an average shadetree could replace a servo pack while draining/replaceing fluid, re-torqueing front and rear bands. I have a small two-car garage with concrete floor, want to raise vehicle on jackstands. Do I need any special tools, are these servo packs (you said 42re xmission) readily available (ie. O'reilly auto parts), could I save myself a buck or two. I usually do anything I can myself. Never tried anything like this. Back in the day, I've changed out whole engines, whole xmission (manual), rear end, brakes, shocks, blown head gaskets, added xmission cooler (this vehicle), etc. Nothing lately. Give me a sign partner.

wingless

The front / rear band adjustment requires a torque wrench and the FSM.

The governor pressure solenoid and valve are attached to the valve body. The overdrive / converter clutch solenoid assembly are attached to the valve body.

It looks like normal tools to drop the pan, remove the valve body (probably Torx drive), remove the solenoids and reassemble.

On mine the "difficult" parts were removing the valve body from the transmission because the connector pokes through a hole in the transmission and it needed extra persuasion to let go.

The assembly is okay. The park rod needs to snake into a cavity, but the design is okay to help it arrive at the correct location.

For sure this is a "shade tree mechanic" job.

ybfcsqs1

Man your quick on the trigger! Just posted my latest, and THERE YOU ARE. Got a siren hooked up or something? I think I'm probably going to give it a go. Hope I can come up with a decent service manual. There is some stuff on Youtube. Don't know about this. Interested in the park cable deal. Your 'crackerjack' guy. Much oblige.

dave1123

Na, he's probably just like me, got nothing to do and just cruises the forum! I'm retired and am on just about every day. It sure was dead Christmas.

I have a 107 page ATSG 42re manual I downloaded from Transtar Ind. in pdf format. I've tried to send it to people before, but it's a mega-file and most e-mail servers won't accept it. Google it and see what you can get. It even has troubleshooting charts and disassembly instructions.

wingless

The ATSG manuals are very well written. They are better than the transmission section of the FSM.

dave1123

Yeah, I've never had a 42re apart and I was curious about the check ***** in the valve body. I've done GM transmissions before and they are a PITA to get the ***** to stay in the transmission when you pull the valve body. You have to know where they go and stick them in with Vasoline when you put it back together unless you have the transmission upside down. The ***** in the 42re are captured between the 2 halfs of the valve body so it's simple.