AW4 slipping in First

First of it an 88, 4.0, AW4. 33" tires, 3.55 gears, 254,000mi

The poblem seems to be limited to first. It doesn't do it all the time, but it has been slowly getting worse. Mostly I notice it while in 4low while starting from a dead stop. It feels like it is slipping then catches like it is not building pressure. Sometimes I have to hold the brake(if on an incline), then rev the engine, then first will catch and its good. A while back I my flywheel broke, breaking the centering pin off the Touqe conveter. I replaced both, but I,m thinking that something else was damaged like the pump, a seal ect.

Trans is full of fluid, and I have tried some lucas oil trans fix with no result. My family has own the jeep since it had 160,000mi, and I know the trans filter has never been changed.

Any Ideas???

Doesn't slip in the reverse gear? If you try to accelerate harshly (but not hard enough to force a shift to 1st) in second does it
do it?

Edit: Engine and tranny cold, shift from Park to Drive with your foot firmly on the brake. Count how many seconds until you feel it go into gear. Repeat with both hot.

Your right. It does slip in reverse, but not nearly as bad as first. As far as how many seconds it takes to engage I don't know the exact count, but I would say around (2-3?) I cant' tell you the exact count as the jeep is about an hour and half away in a friends garge with with broke front and rear shafts. (which broke in first) I know sometimes I can stomp on it quick (at a dead stop) and nothing happens.

What are you thinking?

I was going to say it could be a TCM related issue, but the no 1 solenoid is on for both reverse and first positions. It will operate even with no TCM connected. So that rules out the TPS or TCM as culprits.

This is out of my expertise, but it sounds internal or possible a worn torque converter. I have the AW4 manual though and it mentions several tests. The park to drive time test I mentioned tells general condition of the overdrive, forward, and clutch brake engagement. It says 1.5 seconds is acceptable for reverse, and 1.2 for drive. Hot.

You mentioned line pressure. That can be tested too, but its a long procedure and I dont want to type it out unless you want me to.

If it were me, I'd probably be pulling the tranny and either a. Having it rebuilt or b. more likely getting a JY tranny. Obviously with it out inspect the tq converter.

Oh! I just noticed you said the filters never been changed? I know its just a screen, but any possibility it could be clogged? That may starve the pump

Edit: Line pressure cable is adjusted properly, correct?

Thanks 89CherokeePioneer! I'll try replacing the filter and see what happens.

If anyone else has an idea on the issue I'm open to it.

Have you checked to see if your solenoids (3) are good?

Try unplugging the TCU completely then drive it to see how it shifts with it disconnected.
You will need to shift thru the gears manually of course.
This is a simple test to see if it's mechanical or electrical.

My 88 slipped in first, I changed the oil twice and it stopped slipping, that was about five years ago, I drain and change the Dexron every year, I figure I get a complete change every three years that way. The dealer had put ATF II in the tranny and it didn't seem to like it very well.
My 87 was slipping some, I adjusted some of the slippage out by adjusting the TV cable. I was always suspicious of the dealer then also, it started slipping shortly after a service at the dealership. I never really did have to deal with the problem long though, my wife parked it on the roof and it went to XJ heaven, before it got critical.

8Mud said:

My 88 slipped in first, I changed the oil twice and it stopped slipping, that was about five years ago, I drain and change the Dexron every year, I figure I get a complete change every three years that way. The dealer had put ATF II in the tranny and it didn't seem to like it very well.

Click to expand...

You bring up a good point here.....
Make sure you have Dexron II or Dexron III in your transmission.

Thanks guys. I'll try doing a TV cable ajustment then unplug the TCU and test it that way. If that seams to help I will do a fluid/filter change.

I'll post up my findings in about 2 weeks.

Update!!!!

I finaly got around to changing the filter, and I think that was the problem. My pan has a drain plug and the fluid that came out looked normal. When I droped the pan there was about 1/8 inch of dark sluggy fluid on the bottom of the pan, and both magnets where covered. Im guessing it was cluth materal / burn fluid? Cleaned it all out and it seems to be pulling good again.