Recurring transfer case problems

[InvisibleMan]

When I bought the 2003 AWD Astro 2 years ago, there was a rapid thumping feel on tight turns. I used it this way for several months. I refilled the transfer case with the blue Auto Track fluid, and the problem went away for about a year. Now, on tight slow turns it binds up until one of the rear tires skids repeatedly. I tried a flush and fill of the GM fluid again, but no improvement this time.

The blue fluid that came out looked very dark, but I did not notice a burned odor.

It does this whether or not the ATC fuse is in place. It does not do it when backing up. Driving down the road seems normal.

[LiftedAWDAstro]

After the flush and fill, did you drive in figure 8's in a paved parking lot? That is supposed to get the fluid in between the clutch packs.

[1Gary]

Good stuff Lifted.You be learning me somthin.

[InvisibleMan]

I've done some figure-8's in paved lots, and gravel lots, in forward and reverse. Also mixed in some regular driving. I just dropped it off at a transmission shop this afternoon. They insist that it will only need an encoder motor. I guess I'll find out tomorrow.

[LiftedAWDAstro]

That was the next step. Probably the motor isn't releasing like it should. If they want a fortune, you can do it yourself pretty easily.

[InvisibleMan]

I just picked it up from the transmission shop. Everything seems back to normal, no binding or thumping on turns. Front wheels had some power to them when tested in the gravel.

They replaced the encoder motor. The old one was stuck in mid-position.

Thanks for the information everyone.