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Aw-4 tranny issue with '99

preacherjeeper

NAXJA Forum User
Location
Toledo, Ohio
Just exchanged burnt aw-4 (front seal went and puked all the fluid out) with a boneyard tranny. Exchange went well (nothing broke and no parts left over). Filled it with proper amount of fluid and took it down the road for a test drive. First couple of shifts seemed normal but would not shift into third. Continued to accelerate but as the rpm's rose it would not shift. Seems to be an electronic issue. Been told there are tail shaft speed sensors and I saw three internal selenoids ?? where the filter is. Don't know my next step. Help!
 
What year was the used trans from??? Mid-98 the AW4 came with an input speed sensor that they didn't have before.
 
possible nuetral saftey switch? I know its a long shot, but my buddies 97 wouldnt go into third, I adjusted the NSS and it works much better now.
 
I'm not sure what year the boneyard tranny was, I just told the guy I needed one for a '99. Is this sensor found on the tailshaft? To the second poster: Where is the NSS located?
 
The NSS is on the right side of the trans (big switch). The AW4 speed sensors are on the driverside of the trans. The input is close to the bell housing and the output in under the t-case shifter pivot bracket.
 
If the 1-2 shift happened at the right time and you're not getting a check engine light, you got the correct tranny. If you had gotten a pre-98 tranny it would have been trying to shift a 4x the normal rpm (ie probably not at all).

You might need to pull the NSS and clean it. It's a very common problem http://www.go.jeep-xj.info/HowtoNSSrebuild.htm. Try not to break it getting it off as they're $149 to replace.
 
One of the first things I always do with AW4 equipped XJs, whether a transmission or driveability issue, is to remove the in-line fuse to the TCU or to simply unplug the TCU, then drive it shifting manually. If the problem goes away you have confirmed that it is electrical in nature.
 
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