• 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.

AW4 - Every Gear is "Drive"

S

SpydyrWyr

NAXJA Forum User
Location
Raleigh, NC
*Sorry if this is a re-post, but couldn't find anything exactly like this with a search*

Well, got a 1990 XJ, 4.0, AW4, almost free. The P.O. said it had "tranny problems" that was the extent of the problem description. Got it cranked up and motor sounded good from low to high rpm. Then shifted out of park into Drive and tried to move forward: success! Then shifted into Reverse and tapped the accelerator: it moved forward. Then shifted to neutral and tapped the gas: it moved forward. Then put it in Park and tapped the gas: it moved forward.

Let it sit overnight, started it up the next morning and it was in "park" was able to rev the motor w/o movement. Shifted to drive and drove down the street, seemed to be shifting fine. hit the brakes and it wanted to stall, stuck in a high gear just able to limp home. went to park it and it was stuck "in gear" even while parked again. next morning, back in actual "park."

Unplugged TCU and no effect.

thoughts?

any help would be greatly appreciated.
 
SpydyrWyr said:
*Sorry if this is a re-post, but couldn't find anything exactly like this with a search*

Well, got a 1990 XJ, 4.0, AW4, almost free. The P.O. said it had "tranny problems" that was the extent of the problem description. Got it cranked up and motor sounded good from low to high rpm. Then shifted out of park into Drive and tried to move forward: success! Then shifted into Reverse and tapped the accelerator: it moved forward. Then shifted to neutral and tapped the gas: it moved forward. Then put it in Park and tapped the gas: it moved forward.

Let it sit overnight, started it up the next morning and it was in "park" was able to rev the motor w/o movement. Shifted to drive and drove down the street, seemed to be shifting fine. hit the brakes and it wanted to stall, stuck in a high gear just able to limp home. went to park it and it was stuck "in gear" even while parked again. next morning, back in actual "park."

Unplugged TCU and no effect.

thoughts?

any help would be greatly appreciated.
Click to expand...
Bad NSS or no power too it.
 
NSS would prevent it from shifting into R or N or P ?? I thought it just keeps it from starting in anything other than park or nuetral. Not questioning you, just looking for clarification.
 
SpydyrWyr said:
NSS would prevent it from shifting into R or N or P ?? I thought it just keeps it from starting in anything other than park or nuetral. Not questioning you, just looking for clarification.
Click to expand...
It's called a NSS but it also is the gear selector, it has contacts for, NSS 1-2 3 Drive, and the Backup lights.
That transmission is electrical controlled.
 
Then how can someone drive it normally when it's bypassed?? I also don't think it's the NSS b/c we disconnected the TCU, therefore bypassing all the transmission electronics, and it acted the same way. A properly funtioning AW4 with no TCM hooked up will drive fine other than never shifting out of first. The fact that the transmission still had the same problem indicates it is a mechanical and not electrical problem. At least that's how I understand it.
 
Last edited:
SpydyrWyr said:
Then how can someone drive it normally when it's bypassed?? I also don't think it's the NSS b/c we disconnected the TCU, therefore bypassing all the transmission electronics, and it acted the same way. A properly funtioning AW4 with no TCM hooked up will drive fine other than never shifting out of first. The fact that the transmission still had the same problem indicates it is a mechanical and not electrical problem. At least that's how I understand it.
Click to expand...
With the TCU disconnected it should shift manually when in 1-2 it will stay in 1-2 when in 3 it will stay in 3.
But I think your on the right track, is sounds like a valve body issue.
 
my vote if its worth anything is not the NSS but sticking solonoids.. im not that up on the aw-4 but something say solonoids here
 
I am also going to have to say it sounds like a solenoid issue. Although, i believe at one time I came across a Technical Service Bulletin that mentioned a kinked tranny line (external of tranny) that could result in a similiar issue. I wish I could provide more specifics, but I do not have the info.
 
I know this is a old post but did anyone happen to figure out the problem? I am currently in the same situation.

I have a 96 Cherokee, 4.0HO, AW4, currently every gear is drive, R is drive, N is drive, D is drive, 3 is drive, I cant go into 1st and even in park the vehicle will drive forward until park engages.

This started by the vehicle not engaging into first gear when in drive, i dropped the valve body, cleaned it, replaced the gasket and the solenoids and put it back in. after putting it back in now every gear is drive.

I made extra certain that when i put the valve body back together all the balls went back in there original spots. I am very confident that I did not put this back together wrong.

Any ideas?
 
As suggested already, unplug the TCU and shift with the floor gear shift lever. The manual valve is operated by the gearshift linkage. The valve diverts fluid according to shift lever position. If the transmission is functioning correctly, with the TCU disconnected it should shift manually.

Shift transmission into each gear range. Transmission should operate as follows:
• lock in Park
• back up in Reverse
• not move in Neutral
• provide first gear only with shift lever in 1-2 position
• operate in third gear only with shift lever in 3 position
• operate in overdrive fourth gear in D position

With a bit of Google-fu you can locate an AW-4 Diagnostics and Service Manual.
 
Last edited:
Michael101 said:
I am very confident that I did not put this back together wrong.
Click to expand...

I assume the fluid level is correct? Usually it won't move if that's the problem though. I'm kinda thinking something didn't get put back together correctly, and you're going to be pulling the valve body back out.
 
You must log in or register to reply here.

Similar threads

B
2000 4x4 sport with 4.0 auto trans issues looking for help.
Replies
4
Views
1K
lawsoncl
L
A
Rough idle & CEL with no codes?
Replies
10
Views
3K
alopeks
A
Z
Whirring sound only heard from inside
Replies
7
Views
106
Z.m4v
Z
4
Timing gear?
Replies
3
Views
100
4x4JeePmaNthINg
4
C
Transmission Not Shifting Past First Gear
Replies
2
Views
68
CBJeeper
C
Back
Top