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My auto is shifting all the time, What can i do??

Big Hank

Big Hank

NAXJA member #435
NAXJA Member
Location
Columbus, IN
I got a 93 XJ. I am running 32'' BFG A/T's Also a 4.0L so I assume it would have the 3.55's. I commute on the interstate everyday and the Jeep downshifts at terrible times. It seems like you have to be very gentle on the gas to keep it from downshifting.

I was thinking that i have read where you can do some wiring work and make the tranny stay in the gear you put it in. Or be able to control the torque converter.

New with this xj/auto tranny thing.

Thanks, Gene MJ
 
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AZman is the real expert here but

In my opinion you need to regear it. It will help with the shift points to yur driving speeds.


hinkley
 
I won't swear to it, but sounds like you need to regear, bro. My friend's 2000 has the same symptoms.

lol..figures, Mark beat me to it by 2 minutes..but yeah, I agree.
 
I would regear, but...

I would regear but I am not worried about driving this jeep off road at all. I doubt it will ever see any serious off road. If i drive 75 mph the jeep never has to downshift. I wish i knew exactly what makes the jeep know when to downshift. If it has anything to do with power, I will just do a few power mods to give it that little extra. Throttle body and air tube, maybe header. I just dont want to lose my capability to go interstate speeds. I like knowing i can drive long distances in this jeep if i need to. I have 4.56's in my MJ on 33's and I don't like to push it over 65 on the highway.

Gene MJ
 
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"I would regear but I am not worried about driving this jeep off road at all. I doubt it will ever see any serious off road."

If this is the case, why the 32" meats? You could just get a bit smaller tire and it seems to me that would help.
 
32's cause they are where allready on there. I helped my younger brother lift this jeep when it belonged to him. He was not into the off road thing so he wanted to get rid of it. I got a super good deal on it and that is just how it is. I really don't want to take it back to stock. I understand your thaughts though.

i was just under the impression there was a electrical mod you could do to the tranny.

Thanks for all suggestions, gene mj
 
The only electrical mod I know of has to do with keeping it from downshifting into 1st when in 1-2. Not applicable to your situation.
 
Don't regear for off road just regear to get back to stock. Then the shifting problems because of tire size will go away.

hinkley
 
Leave the shift lever in "3" until you head downhill or get it above 70 mph (BTDT).

3.55:1 gears with the trans in "3" is the same reduction as 4.88:1 gears in OD. You lose a gear with the lever in "3", except for high speed, but it prevents the shift hunting.

The other things to do are adjust the trans pressure regulator cable (near the TB, to get firm shifts) and the brake pedal switch (down on the pedal linkage, to minimize the TC unlocking).
 
My XJ's up on stands so I can't test it, but would it work to just disconect the "kickdown cable?" from the throttle body? There's 3 cables attatched to the linkage, one to the pedal, one to the cruise, and one to the tranny.

Terry
 
Regear.

I run 32's on my XJ and had to regear twice. First time went to 4.10's. Even though this got me back to my effective stock gear ratio of 3.55 ((28" stock tire /32" stock tire) x 4.10) it still shifted a lot on the highway and gas mileage was terrible (11 mpg). Went to 4.56's and it shifted less, and boosted mpg back up to 17. Even though you're not offroading with it, your gear ratio is effectively 3.10, which is really low for any type of vehicle. I'd go with Ed A. Stevens suggestion of driving it in 3rd gear, which only partially solves your problem.
 
Thanks for all the info folks.

Ed, I will look into that brake switch that would effect the torque converter. It kicks down with so little effort that something may need looked at.

Witt, I was unaware that the speedo gear would have anything to do with the tranny kicking down. I will get the proper gear, it was planned, just hadn't had a good reason to get to it till now.

Also, Witt, do you have any pics up of your rig on 31's. Just curious to see how it looks with 4.5 in of lift. Thats the same lift i got.

Thanks for all the good info as usual.

Gene MJ
 
no sry i dont have any pics.. the tires are new and i havent gotten any good/any shots of me since i got em....
sorry
 
Vehicle speed (speedo gear) like Witt mentioned, TPS and probably manifold vacume along with some imput from the TV cable. Probably all imput to the shifts.
A new speedo gear, might help some, adjusting the TV cable one notch up and down and a test drive in each configuration, might have some affect. Most tranny guy´s say the adjustment has to be dead on, or it will cause tranny damage.
I´ve heard tranny guys with a lot more knowledge than I, mention blanking the memory on the computer controls, for the tranny and retraining it. But when they mention this, you always get the feeling, it´s a last resort type thing (like sunbathing near an ant hill/walking through a minefield).
Unhooking the TV cable won´t deactivate it, it will probably cause the piston, to kind of run wild, in the valve.
 
My 700r4 used to do that a lot. Theres a valve I put in that prevents 4 to 3 unless your WOT I wish I could remember what its called but the size is .500 :rolleyes: but it worked so good that I had to manually drop it into 3rd sometimes.
700r4 is in the XJ and it shifted like that even geared correctly 33" and 4.56 (back in the day)
 
Just found the paperwork. Its a boost valve and it creates less or more pressure so it doesnt shift till kickdown does it at full throttle
 
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