1992 cherokee transmission skips 2nd gear

I just bought a 1992 Jeep Cherokee with 193,000 miles or so on it. I have a few things that I used to help me troubleshoot the transmission problem I'm feeling.

For one, when I accelerate lightly, as in normal driving, all the way to highway speeds, I count only three very distinct shifts; It winds up, goes to the next gear (with less 'pickup' than the first one), then the next gear. I'm assuming it's first gear, then third, then overdrive (4th).

For two, I helped myself find out which gear was being forgotten by the tranny by putting the selector in 1-2 and tried accelerating lightly and heavily. I let it wind up all the way to about 6 or 7 grand and there was NO shifting.

For three, I tried downshifting from 3 to 1-2. Unfortunately it downshifted once instead of the two times I was looking for.

If I floor it from a stop, it winds waay out maybe to 3 or 4 grand before shifting very hard to the next gear. This next gear pulls along at a lowly pace. Again I'm assuming this is from gear 1 to 3.

The only time it will downshift when I floor it while moving is when I'm below about 30mph. It'll downshift to first. It has never downshifted from overdrive to third or from third to second.

It's like my tranny completely denies 2nd's existence!

The guy I bought this Jeep from has told me the following about its history: His girlfriend was trying to drive it out of a parking lot when it spewed the transmission guts all over the place. She promptly turned the car off (gotta love mechanically inclined southern women) and found that the tranny cooler line had popped off at the cooler. They got a new hose clamp for it and tightened it back on and put more fluid in it. Apparently the problem with the hard shift/gear skip happened a few days after this incident.

Any idea what could be causing this? Some say it could be a tranny piston seal issue where the piston seals are shot. I don't know much more than basics about auto trans but I think the pistons control the band tension. Makes sense to me. I would think it would cause a soft shift though or an attempted shift or something other than no shift at all. I would like to think that maybe there is an adjustment that is not set right. TV cable is tight at idle. The guy I bought it from says that he replaced the TPS.

odds are its starting in 2nd gear! I've had more then a few friends with the same issue.

I'd drain the fluid and change out the filter. If you have tranny cooler flush it out too.

But if you wanna go on the cheap, a truck with that many miles you could also have a vacuum leak somewhere too! look for cooked, dried out lines. they seem to be everywhere on the fire walls. if you have time pull one out at a time check them. With some of the older jeeps they had some goofy wiring to the dist caps and throttle positioning stuff look for broken or exposed wires there too...

Best of luck

Thanks Offroadwagon, but I think this is the AW4 transmission because of the year (meaning no vacuum lines to the tranny, just wires). It has a transmission fuse in the fuse box and I found on another thread that pulling this fuse will cause the exact symptoms that I'm experiencing. The fuse isn't blown, so I suspect something else must be messed up. (perhaps solenoids?)

It could be missing first gear, though, and just hard shifting into 3rd and a tranny flush/filter replace could indeed unclog some ports. I think I'll take it to a car repair shop and have that done to see what it does.

I've also noticed that it doesn't have any Torque Converter 'lockup'. I hear that the AW4 is supposed to lockup in 3rd and 4th gear, but it definitely doesn't. I can press the gas pedal lightly or heavily at highway speeds and the tach will shoot up >500rpm, leading me to believe that the TC is just slipping. Also the tranny tunnel is HOT. Like I can't touch it for more than a second at highway speeds kind of HOT. Fluid is still pinkish red, not burnt and filled to the top when hot, in park, and at idle.

Sounds like she might be cooked, mang. I'll have alook at it in a few days for free, but a tranny shop will charge you about 125 bucks to do a flush. Hell, you can get a whole used transmission for less than that out of the junkyard.

moneypit said:

Sounds like she might be cooked, mang. I'll have alook at it in a few days for free, but a tranny shop will charge you about 125 bucks to do a flush. Hell, you can get a whole used transmission for less than that out of the junkyard.

Click to expand...

True, but I've been meditating on this for quite a few days now. According to the way the tranny shifts (using two solenoids), Gear 2 cannot be dead if gear 3 works. Gear 2 and Gear 3 both require solenoid #2 to be powered in order to be in that gear. Gear 1 requires solenoid #1 to be powered for it to work. Knowing this lets me know that both solenoids probably work.

Also, the fact that that my lockup isn't happening means to me that there's probably something wrong with the shift controller. It's the most logical guess I think. I can test the resistance of the solenoids from the shift controller plug.... whenever I get a voltmeter.

Haven't done much research on the shift controller itself, but its probably a bunch o money.

bchokola said:

True, but I've been meditating on this for quite a few days now. According to the way the tranny shifts (using two solenoids), Gear 2 cannot be dead if gear 3 works. Gear 2 and Gear 3 both require solenoid #2 to be powered in order to be in that gear. Gear 1 requires solenoid #1 to be powered for it to work. Knowing this lets me know that both solenoids probably work.

Also, the fact that that my lockup isn't happening means to me that there's probably something wrong with the shift controller. It's the most logical guess I think. I can test the resistance of the solenoids from the shift controller plug.... whenever I get a voltmeter.

Haven't done much research on the shift controller itself, but its probably a bunch o money.

Click to expand...

Are you referring to the TCM? If so, JUNKYARD! They'd probably charge about 15 bucks, and they're about a 6 minute job to swap out.

Alright man I'll give it a go for 15$... problem is we're on 12's this week and I got the duty this weekend. haha.

UPDATE!: I changed out the TCU and apparently a new TCU does not fix the shifting issue. Still skips past 2nd and doesn't "lock up" like a TC should. RPM's are never locked in. I figure by now it's probably the TPS (though it's supposedly new) or the TV cable. You never know... they may have changed the TPS without adjusting it. I'll do some research into how to adjust these. I think the TV cable needs no measurement when adjusted but the TPS needs a multimeter (ohm meter) and some simple tools. I'll be sure to check the entire range of the TPS to make sure that it is linear like a potentiometer should be.

I don't believe a 92 has an adjustable TPS. The older "Renix" jeps had slots on the sensor and it was rotated to adjust it. You problem does sound like a potential solenoid problem. Adjusting the throttle-tranny cable will only affect the shift firmness, although if its way out of whack it may not shift at all.

Have you seen this website yet? http://www.transonline.com/transdigest/magazines/1997-10/Shift Pointers/index.html (I think the D2 pin voltage measurements on this site are for the Renix TPS with is backwards from the Chrysler TPS).

Thanks Lawson for that info.

Fixed the problem!

I was about to ohm out the TPS... when Moneypit was under the car and found my problem. He saw three broken wires. Some dumb fart decided to cut three wires under the car then twist the stripped ends coming from the TCU together. All three wires went into a plug on the tranny. Colors of these wires were White, Purple, and Yellow, I think. They all had some color of stripe on them, but I forget the stripe color.

Anyways, as soon as I crimped these wires back together, I took it for a test drive and get 2nd gear (WOO!) and downshift in every gear. Got lockup in 3rd and 4th, and it unlocks when I hit the gas hard or tap the brake. Awesome!

Hope this thread helps someone else out with the same problem, albeit a weird and rare collection of symptoms.

Thanks everyone for your help.

Congratulations! I think you own him a beer.

Yeah that might cause a few problems! I think the white and violet are the wires for the two shift solenoids. Shorting together would indeed cause you to skip a few gears as they'd both be on or off. Not sure who would have done that. An idiot previous owner, or a dishonest shop trying to get return business and sell a new tranny?

The usual troubleshooting steps of measuring the solenoid resistances at the TCU would have given you weird results. It is a good example of why the next step is to pull the tranny pan and measure directly at the solenoids to eliminate wiring problems.

I'm hoping moneypit is just a friend and not a professional mechanic. Just something not right about a mechanic going by the moniker of "moneypit". :}