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AW4 Please help

xj9140

xj9140

NAXJA Forum User
Location
Sacramento, CA
I replaced my aw4 today, with a used one that worked fine when pulled, but has been sitting under a tarp for over a year. Put the Jeep in drive and it wouldn't move! I can't get the tires to move in any gear, Tansfer case in 4low, 4hi, 2hi, still nothing at all. I jacked up the back tires and there was absolutly no movment in any gear, absolutly nothing. I checked the fuse under the hood and its getting power. I've searched and searched, havn't found anything close to this problem. Its a '91HO. The old tranny slipped bad and had burnt atf. The torge converter I used was from the burnt, the reason being was the used aw4's TC got dirt in it. Figured I be better off using the old converter. I know this is not the best way to go about this, but I don't mind the work to much and its what I had on hand. I might buy a new torgue converter, but I don't think this it's the problem. I'm thinking its electricle, Can anybody help? What should I do next?
 
I am not a tranny guru, but I do understand electronics. I would first check the NSS and verify that it is switching correctly. Next, I would make sure that the connections to the TCU were good and check the solenoid outputs on the TCU for voltage in each gear. Note, use a volt meter (VOM), not a test light.
 
isnt the lever to transmission mechanical (park, reverse, neutral, forward), and solenoids do the shifting (1-2, 2-3...)? Hmmm just a thought but it might help someone else think of the solution.
 
If it won't move in reverse, then it is NOT an electronics or solenoid problem. My 93 FSM shows total fill on the AW4 is 8.5 quarts. You did bolt up the TC to the drive plate, right?

Also, did you verify that the output shaft spline count was the same? I understand if they are different, it will bolt up but the output shaft will not actually engage the xfer case input. If you put it in park, jack up the rear and you can spin the tires this might be the problem. What year is the donor tranny?

The NSS controls starter lockout, reverse lights, and tells the TCU when the shifter is in (1-2) or (3).
 
If it's in park and he spins the rear axle, the wheel on the opposite side will spin in the opposite direction......so don't confuse that with a problem.

However, I think he didn't put in enough fluid. The pan holds about 5 quarts alone......when I just drained the pan, all I had to fill was 5 quarts. But since he's filling an empty and fresh aw4, yeah, about 8 quarts or so I've heard as the total capacity.

Transfer case - just fill until it reaches the top fill hole.
 
Last edited:
"If it's in park and he spins the rear axle, the wheel on the opposite side will spin in the opposite direction"

auauh no. with motor running In park and jacked up i can't spin the tires, but any other gear, R,N,D,3,2-1 I can spin them can't feal any diferance in any gear other than park. The splines are right. Like I said this AW4 worked graet when I pulled It, But that was almost three years ago, and its been outside under a tarp ever since. But this doesn't make since to me, Anybody know whats going on with this AW4? I most likely will end up just getting a low milage junkyard replacement, but still I want to figure out whats going on.
 
Blaine B. said:
If it's in park and he spins the rear axle, the wheel on the opposite side will spin in the opposite direction......so don't confuse that with a problem.
Click to expand...

I guess I should have said put it in park and see if he can push the vehicle. Anyway, from his post it sounds like the drive shaft is getting connected through the xfer case to the tranny output since park is locking the drive shaft. That eliminates a spline mismatch and a xfer case problem.

On the t/c, the best method is to unbolt it and installed it on to the tranny input first. Then lift and install everything at once. Otherwise, you run a much higher risk of damaging the t/c or the tranny, especially if the t/c isn't engaged properly when you cinch up the bellhousing bolts. I don't know if this is the problem, but it is possible that something got damaged.

Since you left the t/c in place, adding 5 qts might be about right.

Don't suppose you have a pressure guage with the right fitting to check if you're getting any hydraulic pressure in the tranny?
 
You can't spin the tires in when park? With my XJ I can.....just the opposite turns the other direction.....AKA, when on flat ground, they can't turn the same direction, that's why your vehicle doesn't move. Its in the differential - I believe with a limited slip it would be different. Maybe you have a limited slip?
 
lawsoncl said:
If it won't move in reverse, then it is NOT an electronics or solenoid problem. The NSS controls starter lockout, reverse lights, and tells the TCU when the shifter is in (1-2) or (3).
Click to expand...
Like I said, I am not a tranny guru. I am good at troubleshooting electronics though, so I posted what _I_ would do with the information available.
 
It sounds like you trashed the fluid pump. There is no way you can leave a converter bolted up and cinch the transmission down on top of it and expect it to work. When the converter is installed there are about 4 different sets of splines it engages into, requiring rotation between each set.

That trans is junk now.
 
rpyne said:
Like I said, I am not a tranny guru. I am good at troubleshooting electronics though, so I posted what _I_ would do with the information available.
Click to expand...

Don't worry, I wasn't trying to bust your balls. I was just clarifying based on how the TCU works so he didn't get diverted thinking it was an electronics problem.

I agree with JJacobs that the fluid pump may have been damaged. Pulling the cooler lines and looking for flow as xj9140 mentioned is a good way to look at that.
 
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