zanderman111

Do you think that a fluid change and or flush would help? The shop thought it would only make things worse.

ol"blue

I don't think it would hurt. You might think about having the TCM reflashed. We bought our '04 WJ new and it'd had to be reflashed twice. It now has 88,000+ miles and shifts great.

96GC4x4

Don't mean to highjack, but can you reflash a 96 GC? mines shifting a little funny.

mudfrog

Do a fluid and filter change. Do not flush it. When you do the change add a bottle of Lucas Transmission Fix. That stuff works wonders.

ol"blue

I don't know if they can reflash a '96 ZJ because it doesn't have a separate TCM. The transmissions functions in '96 were controlled by the Powertrain Control Module. When the trans in my '97 was shifting funny I took it to the dealer and had a new crate trans installed. $2,400 w/a 3/36 warranty.
I'd like to hear if someone has any more info on this.

x91j

Mines doing the same thing. Plan is to do a fluid filter change and add lucas trans fix. It slips in 2nd when cold but shifts fine warm. I have a 95 4.0. But I say just do the filter and fluid it won't hurt.

zanderman111

Thanks for all the info. Ill do the fluid and filter change hopefully Friday. What does having the TCM reflashed do exactly and how much does a dealer usually charge? Obviously I am looking for the cheapest good fix here ( I am a college student) but I do want to fix it right. I'll try the fluid + filter change and let everyone know how that works out. The WJ's take ATF4 right? Is there any brand that is "better" than anther that anyone would recommend? Also is all the Lucas tranny fix the same or am I looking for a specific type?

Thanks!

ol"blue

When the dealer reflashed ours it was $100 deductible under the extended warranty. It takes the TCM back to the factory shift points. Ours was shifting late, dragging out the gears too long.
The funny thing about it is it learns how you drive and adapts the shift points to that. My wife normally drives it but if I drive it for a week or so she says it's shifting funny. Well that's because it learned that I drive with a lighter foot than her. After her driving it for awhile it returned to her way of driving.
Also on our 4.7L V8 WJ, when OD is dis-engaged you get a different 2nd gear ratio than when OD is engaged. I don't know if it's the same on the 4.0L equipped models.

zanderman111

Does having the dealer flash the TCM do the same thing as holding the odometer button and turning the key on off on off on off (3 times)? I read this somewhere and tried it. It makes the dash light up pretty colors and then the odometer starts counting 111111, 222222, 333333, etc. Holding the button and turning the ignition on and off clearly does something, but it did not help/solve/fix my problem. So im not sure if it actually flashed my TCM or not.

mudfrog

I would think it has more to do with the bands sense it mainly does it while the transmission is cold. This is usually a sign of the internals and not the shift points. There is only one type of Lucas transmission fix. It's about $10 for the bottle, it is well worth the money. I know guys who had the same issue as you and after using the Lucas product they have gone another 30k miles and the transmission is still going strong.

ol"blue

No, that's similar to checking the trouble codes. >Jeep Horizons :: View topic - Jeep Computer codes (OBDI & OBDII)

zanderman111

Update:
Last night I did a filter fluid change and added about 1 bottle of Lucas tranny fix. I drove it around last night to stir up the new fluid. I just got back from driving it this morning and the slipping problem in 2nd gear has been 80% eliminated! However, clearly something is still not right, because it does still seem to slip, just not nearly as bad and it would be almost unnoticeable to the everyday driver.

I can live with it the way it is, but is something clearly very wrong with my transmission and it just needs professionally repaired? Or is the right course of action just to do another change / flush and add more Lucas tranny fix?

Any ideas are appreciated!

Thanks!

ol"blue

I hate to give advice from a distance, but to do as you stated above will be a lot cheaper than a possible rebuild. It would be fairly cheap to find out if it will help.
Since what you've done has helped a lot, I doubt a re-flash would help any. JMO

zanderman111

Update 2:
I did yet another fluid change and added more Lucas tranny fix. It worked! My slipping problems have stopped completely! THANK YOU to all of you that have given me advice and helped me through this! You have saved me thousands of dollars and I have gained somewhat of an education about transmissions through all this.

THANKS AGAIN TO EVERYONE!

ol"blue

Glad to hear that. Thanks for posting the update.