Question on AW4 problem

I have an AW4 in my 85 4.7L XJ. After sitting for a few hours, it takes about 15 seconds after starting for it to want to move when put in gear. After that, all is fine. I chalk it up to old seals, but I have one interesting problem. If I rev too high under load, ie. ~=4000 rpms, it will act like you put it neutral and the motor will free wheel. As soon as you let off the gas and the rpms drop, the tranny shifts back into gear.

The tranny fluid was changed a couple of times this summer fighting with a bad seal rear seal and a pan leak, so it is fine and at the correct level.

Are you using dex/merc or atf-4?

Sure sounds like a low fluid issue. Seems likely, when it is cold you have insufficient fluid until it heats up and expands, at higher RPM's you get a little foaming and it starts acting up again. If it is a low fluid level issue it should act up on inclines also, maybe. If it is a low fluid issue it is likely way low, I never noticed when the shop filled mine almost four quarts low.

The first step for me when the tranny is acting up is to check the TV cable adjustment.

Shifting from neutral to drive or reverse there shouldn't be any more than a 1-2 second lag before it engages.

Likely not to be your issue, but I actually stuck the wrong dipstick in the wrong tranny *once*. My nick name was *dipstick* for weeks after that one.

Demonoid369 said:

Are you using dex/merc or atf-4?

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When they (the shop) filled mine with ATF 3 it would slip in first and a little in second gear when it was cold. It got worse on very cold mornings.

I agree with the above. If a shop did the work (especially if you chose a Skippy Lube outfit), be afraid...very afraid.

Possibilities include low fluid level, wrong fluid, clogged/incorrect filter, high fluid levels causing foaming, TV cable out of adjustment, misadjusted bands and an incorrect dipstick. I have seen shops inadvertently swap dipsticks between cars.

I am running Dex/Merc. It is definitely not low on fluid. I bought a new dip stick from the dealer some time ago.

Like I said, after the first 20 seconds, all is great when you shift between gears.

A quick test is to block the wheels, put on the parking brake and throttle down for a few seconds in gear and watch your RPM gauge. Should be between 2100-2400. My 88 is a little lower than this.

Could be an iffy solenoid. You can ohm test the solenoids from the TCU plug. This way you test the wiring and the solenoid at the same time. You might want to also volt test a solenoid wire with everything connected and that solenoid activated, right after cranking it cold for the first few seconds, low voltage and most anything is possible. A marginal battery is likely to show up first by flaky component function, like the IAC, maybe the same for the solenoids. My number 1 solenoid has low resistance, it hasn't caused any real issues yet. But My shifts to reverse got long, a hesitation, when my battery was on it's last legs.

Sounds like low pressure for some reason and after it heats up a little, the pressure comes up. Various reasons for low pressure, the one I'm most familiar with is thick fluid from really cold weather.

This may be a dumb question, but I'll ask anyway. To address 8Mud's question about the fluid level, how much fluid was added after the pan was drained?

was the filter changed when the fluid was changed?

I ask because the symptoms lead me to a plugged filter.

slow to engage, and cavitation of the pump over 4k rpm

8Mud said:

When they (the shop) filled mine with ATF 3 it would slip in first and a little in second gear when it was cold. It got worse on very cold mornings.

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thats why I figured i'd ask him as the atf-4 has a reputation of making the aw4 slip

When was the last time you replaced, adjusted your TPS?
I had an incident recently with my Renix heep and the AW4 acting like it was in neutral sometimes or not shifiting right. Adjusted my TPS, and it went away. Never had the issue of cold start not moving though. A solenoid failing is definitely possible. Maybe disco the TCU and see how it works manually?