Help from tranny Guys????

Just got my motor running and my 44 in the rear and went on a test drive. Its an 89 xj, 4.0, 4:56's and 34's. SO, I think the trans is working improperly. It shifts into 2nd at about 15 mph, then to 3rd at like 20 mph and into 4th at around 40. I have the aw4 i believe and am not sure where to begin. It stinks because i have a new motor and it feels gutless!!! no power at high speeds and wont kickdown like it should. Anyone have this prob? is it a sensor or adjustment to be made??
Ive been told that with 4:56's and 34's i should be back to almost stock highway performance other than the weight.Any help please?

Try adjusting the throttle position sensor. makes a big difference in how they shift. Transmission cable regulates stiffness of shifts.

John McHorney

is there a writeup on adjusting the tps on here? any other ideas????

Did you change the speedo gear? If you didnt you probably arent going the aem speed the speedo says.

When I went from stock tires and 3.07 to 33" and 4.10, my truck felt gutless too. No top speed, no takeoff power (and this is with a 5 speed!) because the high torque RPMs were done before the truck even got moving fast. (I think it's more Renix than HO problem because HO makes peak torque at a higher RPM) I now have 3.73 and it goes like a rocket by comparison.

carnuck said:

When I went from stock tires and 3.07 to 33" and 4.10, my truck felt gutless too. No top speed, no takeoff power (and this is with a 5 speed!) because the high torque RPMs were done before the truck even got moving fast. (I think it's more Renix than HO problem because HO makes peak torque at a higher RPM) I now have 3.73 and it goes like a rocket by comparison.

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let me get this straight, you geared to 4.10 for some 33's then regeared AGAIN to 3.73??? that makes no sense and is a waste of money unless you swapped in another axle with 3.73 already in it

my problem has to do with the way it shifts in my opinion too early. especially from 2nd to 3rd....it shifts into second and almost instantly goes into 3rd.....not sure the issue??

i've never really been satisfied with how auto trannies shift, so mine is manually shifted. The only reason I wish I had the auto hooked up is so I could let girls drive without having to explain a manually shifted auto tranny.

ok, so ill try the tps, and hope it fixes it i guess?

skyjackedxj96 said:

let me get this straight, you geared to 4.10 for some 33's then regeared AGAIN to 3.73??? that makes no sense and is a waste of money unless you swapped in another axle with 3.73 already in it

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I actually went from 3.07 with stock tires to 33" tires, then to 3.73 gearing (already had the axle from a 4 banger Cherokee. Welded new pads on SOA and it was good2go!) Then, thinking the power would be better with 4.10 and 33" tires, I swapped another Comanche axle in (welded new pads on SOA. Piece of cake with a level and a couple blocks under the axle) that had 4.10 gearing. Power took a MAJOR dump! I had lots of RPMs, but no takeoff power. It would wind out before the tires even got moving! It felt like trying to drive around on the roads in low range (which since it's a 2wd trans, wasn't possible)
Would've been fine for rock crawling, but sucked for a daily driver. My fuel economy dropped to nearly 10 mpg too (I ran 3 tanks before giving up and switching back. Yes, the speedo was regeared to match at the same time) My speedometer read 90 mph and people were honking at me for going too slow in the slow lane on I-5!
When a Ford Escort with a bad headgasket passed me, I gave up!

UPDATE!!!
ok, so i adjusted the brake switch and the tc will lock up but at about 40mph...is that close to when anyone elses locks up?
Its still off though. it seems like way to low a gear for the speed and when you gas it, it wont down shift, but when i let off the throttle, it will unlock back into 4th.
So, continuing problems are:
2nd to 3rd shift only takes about 5 mph.
tc locks up at about 40 mph...seems low...boggs down
No kick down....
Help anyone?
i tried ajusting the TPS but i started another thread because it wont adjust to 83%...maybe part of the problem. it adjusts to like 90 at best