Occasional O/D problem and wrong gear problem

[mtsu4000]

I have a 95 GC 6cyl. and recently after putting it into drive, it will start out in 3rd gear without using 1,2 or overdrive. The overdrive button will light up (which it usually doesn't do) before starting. The strangest part is that it is very selective as to when it does this. I can usually get it to return to normal (starting in 1st upon start up) by shifting down to 1st then to park, then back into drive. Does anyone have an idea of what I can do to correct this problem? Thanks in advance

[kwj929]

I have the EXACT same problem with my 95 JGC 6cyl. It has been doing this intermittently for several months. I brought it to Aamco who replaced the Governor Solenoid. They also tried to fix the speedometer which hasn't worked in almost a year... but they couldn't fix it. All that for $800 and it still exhibits the same intermittent problem that you describe. I've taken it upon myself to self-educate and will try my best to either replace appropriate sensors or at least to be able to talk the talk if I have to go back to a mechanic. I haven't attributed this problem to the broken speedo since the problem began well after the speedo broke. In any event, I hope someone can offer some clues. I've come across this same symptom on other forums, but with no conclusive results of a fix. I may try to replace the speedometer sensor as a first course of action.

[mtsu4000]

Well if you do find out what sensor, solenoid, etc. is causing it to do this, let me know. I am researching it myself too, and I will let you know if I can figure it out.

[LELeach]

I had a very similiar problem with my 4.0 1994 Grand Cherokee Loredo 4X4. It began dropping out of overdrive. About 50 miles after this started occurring and while traveling at 75mph on I-26, the transmission literally disentigrated internally. The resucing dealer told me there were no reuseable parts including the case. The output shaft bearing had seized. The bottom line was $2977 for a factory rebuilt x-mission. Good Luck.

[dksob81]

mtsu4000, Does this happen after driving for awhile or after 1st start-up in the morning?

the reason I ask, if the O/D light come on, this means the TCM is disabling OverDrive. The TCM will disable OVERDRIVE when the tranny begins to overheat, it does this too cool the transmission, could explain why LELEACH tranny disentigrated...

[dksob81]

also, make sure the tranny fluid level is where it should be, check with engine at normal operating tempature and with Tranny in NEUTRAL...

[mtsu4000]

DK--Thanks for the info. . .To answer your question, it started out one night about 4 months ago, the OD light (which never came on before) came on when i started it. It stayed on and the Jeep stayed locked out of everything but 3rd for the whole ride home. Since then, it does it more and more frequently. I would understand if the TCM would lock it out of the gears if it was overheating, but as weird as this seems, the hotter it is outside, the less likely it will lock out. What does that mean? Is the trans. temp sensor going out? If its 90 outside it will most likely start up in 1st, but if its any colder it will take a few tries before I can get it to shift normally. I had the trans fluid changed about a month ago, and its still level and clean. If anyone has an idea, let me know. Its getting harder to get it to shift correctly each week

[mtsu4000]

LELeach--I had a very similiar problem with my 4.0 1994 Grand The bottom line was $2977 for a factory rebuilt x-mission. Good Luck.[/quote] Thanks and that sucks about your x-mission. Thanks for the help

[LELeach]

Originally Posted by mtsu4000

LELeach--I had a very similiar problem with my 4.0 1994 Grand The bottom line was $2977 for a factory rebuilt x-mission. Good Luck.

Thanks and that sucks about your x-mission. Thanks for the help[/quote]

You're welcome......I hope my bad luck helps prevent yours.

[rpady]

Originally Posted by mtsu4000

I have a 95 GC 6cyl. and recently after putting it into drive, it will start out in 3rd gear without using 1,2 or overdrive. The overdrive button will light up (which it usually doesn't do) before starting. The strangest part is that it is very selective as to when it does this. I can usually get it to return to normal (starting in 1st upon start up) by shifting down to 1st then to park, then back into drive. Does anyone have an idea of what I can do to correct this problem? Thanks in advance

mtsu4000,
We have the same problem with our '95 GCL 6 cyl. auto. I would love to find out what the fix is. It can do 3 different things, work great, start in 2nd and shift to 3rd only or just start out and stay in 3rd only. The overdrive OFF light either stays on or will not come on.
Don't believe it's a tranny exploding problem like someone suggested. Has to be a sensor or control module. But, which one????
Will let you know any findings and please do the same, thanks, Rob

[dksob81]

well RPADY your prolly right about it not being an exploding tranny problem, the only good thing about ELECTRONICALLY CONTROLED TRANSMISSIONS is about 90% of the time the problem is gonna be an eletrical sensor or solenoid and such.

Ok guys I was doing some Home work also,

You have to disconnect every connector clean it (GOOD) and use conductive switch grease on the connections and plug them back in, you have to do this on just about every one, it has to do with no signal or a falt signal not or being sent to the ECM.

This makes sense, after dude got a new trans the connectors would have been replaced or cleaned of a new one connected fixed the bad link.

Let me know if this works.

Originally Posted by ramairgto72

Ok guys I was doing some Home work also,

You have to disconnect every connector clean it (GOOD) and use conductive switch grease on the connections and plug them back in, you have to do this on just about every one, it has to do with no signal or a falt signal not or being sent to the ECM.

This makes sense, after dude got a new trans the connectors would have been replaced or cleaned of a new one connected fixed the bad link.

Let me know if this works.

I forgot to add this The info said to uses nothing but contact cleaner to clean the contacts and to use the conductive grease lightly. You can get the contact cleaner at any Radio Shack.

A few of you have written to me, so I will kinda give everyone here the same info I gave them.

All the connectors locations.

Thats a good one, I could try to get the wireing grid from my program and Book, but the connections are not listed.

The connectors are easy to get messed up, the contacts inside the connector can be not connecting even if the plug in snaped in, a simple audio type ohm meter from walmart would be able to tell you if somethings not together.

One contact on a wire on one male side of the conector and the other on the female connected/ing wire one the other side, I know that sounds like alot of work, but short of the dealership thats what you got.

On top of that you have sensors that feed info about the what the engine is doing and inlet temp, engine temp, outside temp, rpm, VAC, it's a dam mess, what happened to a 12V kickdown switch and a Vac line?(TH400) even the Army still uses them!

I would also like to note here that "I don't have all the answers"
I do have alot of leg work, and I built my 1972 GTO from the ground up, along with wireing in and setting up injecction systems, and have a wide collection of service books along with some engine theory, chassie, supercharging/Turbo and NOS, and intake design along with a spat of engine rebuilding books, but i'm not a pro on any of it, i'm allways learning, but aren't we all....

The info come from my CD rom for Jeep by Nichols Publishing (Chilton) I looked up problems with the trans and in bold print it stressed about the connections!

If anyone fixes the problem/s I would like to know!

I can't help to quote Mr. Scott (Star Trek)
"The more complcated the pluming, the easyer it is to stop up the drain"

[rpady]

Fixed mine today with a TCM.