• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

1998 XJ trans low/2nd gear & TC lock-up?

chucknewell

NAXJA Forum User
Location
So. Cal.
I've searched through the forum and the 'net but all the info about the auto-trans shifting mod seems to be for the pre 1997 XJs. I read one that said it wont work on the '97-2001 XJ. I'm from the school that anything is possible. Does anyone know what is different about the late model XJ and what the procedure would be for the mod?
Thanks
Chuck
 
I have a '99 and would be interested as well.
I would guess you would need a wiring diagram and go from there.
I can't realy read those too good anyway.
but I have lived with the 1-2 for a couple years and it doesn't really bother me any more. Just looking for more cheap mods.
 
Anyone know? I am eagerly awaiting the response as well!
 
Maybe I don't understand this.

I have a 97 XJ with a 242. and auto tranny. When I put mine in 1st, it stays there, wont go to 2nd. when I go up to the "3rd" indicator, then it will shift to second and also onto 3rd.

is mine the only one like this. I think it is all stock.

Jason
 
On my 98 if you put the auto in the 1-2 position it will go back and forth between 1 adn 2. If you put it in 3 it will use all those gears. I think it was GO-Jeep (not positive on this) that has a tech article where if you put it in first or second it stays in first or second. Not both. There are times coming down a hill that I want to stay in 1st not shift to 2nd.
We're hoping that someone know the answer to the question of whether it can be done to the 98. Hopefully next week I will be able to get back into the garage and can maybe try it on my 98 and see what happens and report back.
 
Mine is a 98 with an auto. Put it into 1 stays in 1. Only way to get 2 and up is to either go to 3 or D (yeah smart asses, R works too).
 
martianxj said:
Mine is a 98 with an auto. Put it into 1 stays in 1. Only way to get 2 and up is to either go to 3 or D (yeah smart asses, R works too).

I have a '98 w/ auto. It drives as it has since new.

If I have the shift lever in 1/2 and accelerate to get the tach up to around 4,000 rpm (haven't looked at the speed as I'm totally focussed on the tach....hate revving a straight 6!), the transmission will shift into 2nd, and I can continue to accelerate.

Conversely, if I'm travelling down a gravel road at 35 mph, or so, and shift into 1/2, the tranny will shift into 2nd. As soon as I allow my speed to drop below about 28 mph, the tranny will slam down into 1st gear....this can be interesting on snow with a No-slip locker in the rear.

If your tranny won't upshift into 2nd gear as you accelerate (while in 1/2), then I'd suggest that there's something wrong with the tranny or the TCM.

Bones organized a "sort of" Compushift group-buy back in the old days, and I don't think anybody was able to get the Compushift to work seamlessly with the DiagII computer.
 
No one seems to know. From what I've been able to find out so far it seems that the problem with doing this mod to the 1997 and later XJ's has to do with the OBDII computer. That's On Board Diagnostics (I guess). I've e-mailed Mopar and will keep you'z updated as I find out more.
Chuck
 
This has been a question that has never been answered. I know some about electronics and have done the 1-2 mod on mine and another XJ (90 and 91). I also have a factory service manual from a 99 and have sat down trying to figure it out for those years. It does not look possible. The ECUs are completely different and by the looks of things, the fluid paths are different in the newer trans than the older trans. On the older ones, you can just activate the #2 solenoid and get 2nd gear.

I'll sit down with the manual again and see if I can figure out a way to do so, but not having a vehicle to try it on will be a problem. Even if I did come up with something, would you really trust me enough to try it? :D

As for why do the mod, here's why I did mine:

I was wheeling in the snow in Oregon with it locked in 4lo. I was using the selector in 1-2 for the control and engine braking. We'd sometimes get some speed on the flatter portions of the trail where first was revving high. The only way for an AW4 to go from first to second without moving the selector is to reach around 4700 RPM where the TCU forces an up-shift, but then when you slow down, it slips back into first. While wheeling along in first, I wanted second. To get second and not third, you pop it into 3 and shifts into 2nd or 3rd, then you pop it back into 1-2 and you get second, but when you slow down enough, it goes back into first. In 4lo, when you the TCU goes back into first, it is somewhat violent, and when on the snow, it causes all 4 tires to momentarily lose traction. I didn't feel completely in control when this happened. This is probably one of the best mods, and others will agree, but like stated, it's not available for 96 (some 95s I believe too) and newer.

Steve
 
Back
Top