westafur

I have an 89 XJ,with the AW4 tranny. The other day it just stopped shifting. The more I looked at it I realized that when I hit 5000 rpms it will shift smoothly BUT if
I let off the gas, it drops itself into neutral. After dropping into neutral, I can feather it and it will kick back in gear....has anyone experienced this before? what could be causing this? The 2 shops I have tried to take it to refused to look at it saying that it was a weird year of Jeep and they didnt have the correct equipment to run diagnostics on my tranny so I am stuck diagnosing it in my apartment parking lot with my mediocre skills......

Dave51

What type of fluid are you using and when's the last time you changed it?

Fun reading in the can:

https://cdn.xjjeeps.com/pdf/en-us/aw...nformation.pdf

westafur

Valvoline DEX/Merc. I changed it within the past few weeks after the tranmission stopped. Fluid looked good. I dropped the pan and replaced solenoids and filter.

lawsoncl

If it's trying to start in 4th gear with the shifter in (D) then check the fuse in the wiring harness near the trans computer. Check and clean the transmission wiring harness connectors (see http://cruiser54.com/?p=58). If it's just plain not upshifting, check and adjust the cable from the throttle-body to the transmission (see https://www.cherokeeforum.com/f2/free-quick-fix-41821/). If that's disconnected or really badly adjusted, it won't shift. Also if the rear output speed sensor is bad, it won't upshift. Also look through Cruiser54's other great tips, particularly refreshing the ground connections (www.cruiser54.com)

Dave51

If you unplug the TCM does it shift manually?

If you haven't done it already, test, readjust and/or replace throttle position sensor.

Dave51

It's all in The Book:

MANUAL SHIFTING TEST (1) This test determines if the problem is related to a mechanical or electrical component. (2) Stop engine and disconnect TCU or TCU fuse. (3) Road test vehicle. 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 (4) If transmission operates as described, proceed to next step. However, if forward gear ranges were difficult to distinguish (all feel the same), or vehicle would not back up, refer to diagnosis charts. Do not perform stall or time lag tests. CAUTION: Do not overspeed the engine during the next test step. Ease off the throttle and allow the vehicle to slow before downshifting. (5) Continue road test. Manually downshift transmission from D to 3, and from 3 to 1-2 position. Then manually upshift transmission through forward ranges again. . (6) If transmission operation is OK, perform stall, time lag and pressure tests. If transmission shifting problem is encountered, refer to diagnosis charts. (7) If a problem still exists, continue testing with DRB II tester.

cruiser54

Pay attention to lawsoncl and Dave51.

westafur

Awesome, I will give this a try when I am home and see what the outcome is.

westafur

Unplugged TCU, 1-2 worked as supposed to. 3 worked normal but (D) acted like it was in 1-2 again...

Dave51

How about reverse?

What brand of solenoids did you get? Why did you change them? If they were working OK do you still have them?

Dave51

Or does this

mean the problem started and in an attempt to fix it you changed all the solenoids?

westafur

Reverse, neutral and park are all fine. Yes, once the issue began I replaced the solenoids in an attempt to fix it.

Dave51

No metal in the pan when you looked?

The next thing to look at would be the valve body, but IMO it would be better to change out the transmission.

Having first and third indicates the solenoids are good, as probably the old ones as well.

With the absence of any racket, you could try driving around in the present state and pray to the xj gods it self-resolves.

See if lawson has any thoughts.

westafur

No metal in pan at all and fluid looks good. I have been told to trash the transmission and get something else.... haha so very strange, this was my daily driver for over a year and no issues, as soon as I buy a truck my xj stops sifting... I thinkn the Xj gods did it....

lawsoncl

This was done with the TCU unplugged which eliminates the tcu and solenoids, so we're looking at a mechanical issue. Valve body or clutch/brake issue. The stall test in the AW4 manual Dave linked might be helpful, but unless you have the means to tear into and rebuild the tranny, you might be looking for a used one.

Make sure the throttle-body to trans cable is still attached and adjusted.