I just rebuilt a 42re that had perfect fluid. PO had changed it and removed all the metal. Many times you won't have bad looking fluid.

Did you even read what I said? Because you basically just said what I said.

So what's the problem?

Dextron/Mercron only. Don't waste the money on the ATF 4. ATF 4 was designed for the newer style electronic transmissions.

Also OP, there is a TCU (Transmission Control Module) located under the passenger side dashboard and a NSS (Neutral Saftey Switch) located on the passenger side of transmission. These two controls help determine what gear the transmission should be in. We will also be checking the TV (Throttle Valve) cable as well. There is a write up here on cleaning/repairing the NSS. Try cleaning that then check for original problem. If original problem still exists after, we will then move to diagnosing the TCU and adjusting the TV cable.
So in recap, fluid is in check, now clean NSS and report back with results.

It sounds like you are not building pressure until the fluid gets warm. This usually is a problem with older hard seals inside the transmission.

After you do the flush get back to us. The aw4 is an electronically controlled transmission . However as you stated everything is fine once it's up to temp. Which would mean it working properly at that time. Usually an electrical problem is not temperature controlled. And/or can happen at any given time or clear up at any given time. Or just don't work period and consistently does not work.

If it's consistent in the scenario you originally described I would bet a mechanical problem rather than electrical. And as usual I hope for your sake I am wrong.

Actually some problems can be temperature controlled. temperature and resistance are closely related in a lot of instances. The solenoids inside the AW4 are one of those said components. Hence why a solenoid check at the TCU is performed after warming up the fluid.

You are right.
I meant what it sounds like.

You can also bypass the tcu completely and check the transmission for a mechanical related problem. Remove the fuse or unplug the tcu. Drive (3rd)will act as 3rd only with no slippage. 1-2 will be first only with no slippage. If you have slippage with the tcu disconnected then it's a mechanical problem normally.

But i still would suggest a fluid change first. Making certain the fluid level is checked in neutral while running.

What is the connection to the NSS in this situation? Isnt it only on start up that its a big factor or does it work further with the transmission to engage into certain gears once the jeeps running??

Sorry goof up post

The nss works with the speed sensors and the tps, through the tcu to tell the transmission when to shift.



Since you are slipping at startup I would point the blame elsewhere. As the electronic control mainly effects 1-2, 2-3 shifts and not start up. But you never want to completely rule out electrical problems. Especially if you are trying to communicate through the internet. LOL

Edited 8)

And keep in mind multiple problems are always possible.

Here found this in the manual for you.

The NSS essentially tells the TCU what gear or gear range you've selected like "Hey!, I'm no longer in Park, I'm in Drive now. Switch the solenoids to go forward. Chop chop!"

There are about 4 things that control your gears and shifting on the AW4. Having a brief understanding of how all these things work and how they work in conjunction with each other will help you to figure out where certain problems may lie.