Transmission vacuum leak?? help
 

i have a 90 cherokee with an inline 6 and today it started acting weird. it will not shift out of first gear or atleast thats what it feels like. my dad told me it sounded like a vacuum leak in the trany. but i cant find a vacuum hose that goes to it or where it starts does anyone know where the vacuum hose on the transmission is.

That's because there are no vacuum controls on an AW4 trans.

What if you put the lever in 1-2 and then move it up to 3 and then 4/OD while driving? Dos it shift?

theres no vacuum hose on the transmission? its a automatic transmission 4wd
i tried down shifting and it doesnt do anything different.

Some automatic transmissions used vacuum modulators that required a vacuum line, yours isn't one of them. You have an AW4, it shifts electronically using solenoids controlled by the TCU, or manually through the valve body using the shift lever.
What does the fluid look and smell like? Is the level correct?

Look underneath your glovebox and you'll find the TCU (Transmission control unit). Small metal box. It should have an inline fuse. If it's blown, replace it and see how it works.
If it is not blown, remove the fuse, unplug the connector and try shifting manually. Note that in 1-2 the shift to second doesn't happen until you hit relatively high rpm, but it should eventually shift. If you have manual gear changes the Trans is OK, you have an electrical problem. First electrical suspect in a poorly (or non) shifting AW4 is the TPS (throttle position sensor). Any driveability problems aside from the trans issue?

thanks. im going to go check it out and see what i can find. other than the trans it runs good besides when i get around 60 mph it shakes alot and when i try to brake from higher speeds it shakes bad too i know it shakes when braking dur to warped brake rotors but i havent figured out the shaking at high speeds its not as violent as death wobble. im thinking it could be alignment issues and where is the throttle position sensor?

I am having the same issue with my 96 Sport 4.0. I disconnected the TCU and found that my tranny is mechanically fine, it shifts manually. I have replaced the TPS twice and I still have the same issue. Could I still have a bad TPS? Also I did a fluid and filter replacement and adjusted the throttle valve cable as well. This is my only vehicle and I drive 80mile round trip to work so I need help ASAP

Cruiser’s Trans Plug Refreshing

Over near the transmission dipstick tube are 2 rather large connectors. One is black and the other gray. These 2 connectors carry all the info between TPS, TCU, NSS, speed sensor, and transmission solenoids.
Unplug each one, visually inspect for corrosion or bent pins, spray them out with electrical contact cleaner and plug them back in.
　
Additionally, if your Jeep is an 87 to 90 Renix, it’s always a good idea to reach up under the glovebox area and unplug the connector to the TCU and spray it out along with the receptacle of the TCU. While you’re there, find the fuse right in that area for the TCU. Remove it and spray out it’s receptacle and clean any corrosion from the fuse.
Revised 9-10-2012

not to steal the thread, but if you shift it after unplugging the tcu in 1-2 it should shift from one to two correct, and then up through drive and if this isn't happening, then you have an issue. just want to be sure, before i go buy the solenoids and a tcu from the junk yard. thanks

I believe 1-2 stays in 1, lever to 3, lever to OD.

No 2nd gear without TCU.

THANKS!

I have given up on this. I just disconnected the TCU and shift manually. It works fine like that. kinda like have a stick without a clutch. what is if any harm to this?

"what is if any harm to this?"

Keep a new shifter cable handy.

Other than you're skipping 2nd gear?