AW4, Rebuild? Your opinions wanted

[knever3]

I have a '90 AW4 in my truck with the 242 transfer case and it shifts slow even with the sport shift on.  I think it has some slippage when I really get on it because the throttle doesn't seem to match up with forward movement.  It seems the torque is absorbed by the tranny.  I have a 4.7L stroker and it barely spins 1 wheel through 1st gear.  

 

I went through the 242 and it works good so I really don't want to upgrade the input shaft to the 23 spline.  I know the 23 spline is "slightly" stronger, but has anyone actually broken one?  

 

Do I pull it and have it rebuilt this fall?  It has probably 230,000 miles on it.  If I have it rebuilt I want them to hot tank it so it is cleaned, I pressure washed it before putting it in, but it's still filthy.  It has that Tennessee sand/mud baked on.

 

What would you do? 

[89 MJ]

What would I do? AX-15 swap it. 

Realistic answer, though, get it rebuilt. 

[Jesse J]

[cruiser54]

Let's not jump the gun here.

 

I would first adjust the throttle valve cable.

Make sure it has Dex/Merc ATF in it.

When is the last time the fluid was changed?

 

What year is the truck? There were different TCUs used over the years.

I would bypass the Power/Grandma trans switch. They fail frequently and default to Grandma mode.

THE HISTORY OF THE 4.0

BYPASSING THE POWER/COMFORT SWITCH

AUGUST 6, 2016 CRUISER54 42 COMMENTS

Even though the indicator lights up in your Power/Comfort switch, that does not mean the switch is working and putting the Transmission Control Unit into Power mode.

The switches had a high failure rate.

Remove and unplug the switch. In the harness are 3 wires.  One has a stripe, one is tan, and the other wire is black.

Make a 4″ jumper wire with a male spade at each end.

Plug one end of the jumper wire in the cavity for the tan wire and the other in the cavity for the striped wire of the harness and you’ll be in permanent Power mode.

Stuff the harness back in and reinstall the switch for looks if you want.

Make sure the 7.5 amp “Trans” fuse in the fusebox is good.

If you happen to have a 91 or 92 XJ/MJ and it has the Power/Comfort switch, just jumper the Tan and Blue wires in the harness plug.

NEVER include the black wire when jumpering!!!

 

 

[knever3]

I'll give those a look, it shifts when it is supposed to up and down and the torque converter locks up like it should.  I changed the fluid and filter when I put the truck together maybe 10k miles ago at the most.  The TCU and trans are from a '90 XJ as my truck is an '87 MJ.  I will also check the switch, I notice it does work ad shifts slower or slips more then set to the comfort mode.  Might as well bypass it since I will never use it anyway.

 

Thanks for the tips Cruiser once again!

[cruiser54]

You used Dex/Merc fluid?