AW-4 Problems

Just wondering if anyone else has experienced this problem with there aw-4's? My tranny is stuck in first gear. It will shift from park to reverse to neutral to drive, but in drive it will not shift out of first. It will not manually shift out of first either. The tranny has 285,000 miles on it without a rebuild so i'm guessing its due. Just wanted to know if there's something small I can replace to fix this or am I in for an entire tranny rebuild? And on that note does anyone know a good place to buy rebuild/overhaul kits?

Since you don't say what year your XJ is, I can't tell you offhand where to look - but there is a fuze that is separate from the fuze box which controls power to your transmission control unit. Since the AW4 is electronically controlled, it sounds like you have popped the fuze to the TCU, and it is therefore not shifting forward speeds. Reverse and Neutral are mechanically controlled by the shift rod, so they will work normally - but the forward speeds are electronically controlled by solenoids.

If you have your FSM, it will tell you where to look for the fuze. If you don't have an FSM - why not? Get one - you'll thank me later...

BTW - I have a decent selection, so if you tell me what year I can probably point you in the right direction. If I can't someone else here probably can....

IIRC, it's a 7.5A fuze. I think it's in an inline holder.

5-90

Its a 1991 4.0/aw-4/np231. Thanks for the help
one more thing, if I drive it alittle and let the tranny warm up it will start shifting, so I don't think its a fuse. I will check it though.

Have you checked the fluid level?

Fluid is fine, I added some tranny slip fixer and it didn't help.

Just FYI, the AW-4 seems to be a very picky transmission about the fluid in it. Synthetics and additives are often reported to be ineffective or potentialy problematic for that tranny

They may have changed the location by 91, but in the earlier ones, there was an inline fuse in the harness leading to the Transmission Control Unit, which is located in the lower dash beneath the glove compartment. Look for the yellow wire. It's probably worth checking, though my understanding is that when the fuse is gone, it should still manually shift into 2,3, and 4.

Just curious, but is the trans actually not shifting or are you just not willing to rev it high enough in first to make it shift? A bad TPS can delay the 1-2 shift untill redline (5000rpm+). Just my personal experience with my many TPS related shifting problems.

Unfortunately Jeep wasn't nice enough to put a Tach in my XJ. I've pushed it to where it no longer accelerates, about 30 mph in first gear on flat road. I'm sure thats near redline. I'm going to go look for that inline fuse now, anymore thoughts would be appreciated. Thanks for the help.

Hi! I have a 91 with 150,000 and it was doing the same thing. It was the TPS that was bad on mine,shifts ok now. John