Chevy & GMC Vans

Ok, I've read about flushing and re-juicing the transfer case.

What do you use to flush out the old?
(Yeah, besides the special GM 'pull chain' or aftermarket propwash... )

I know the new juice is dealer only, no prob.

I figure with the ride at 102 K, prob never been flushed, and with the amount of highway miles I do, it's a good maint thing to get outa the way.

i was think the same thing last night on my snowy highway drive home (which was fun since i was passing everyone except some transports with ontario plates ) but i thoght i should do my transfer case since it's probably never been done and i thought i heard a wine from my rear-end figure why not do them all together (F,T,R) and get it over with

I don't think flushing with anything is necessary if you aren't having any problems.
The manual talks of checking levels and adding, but I don't believe there is any scheduled change of fluid.
I would pick a warmer day drive the van to get the fluid mobile and drain/add new.(GM P/N 12378396)

The 1999 and newer must be done every 30,000 miles or you risk having weird driving issues with binding or surging while accelerating. The These newer t-case take the GM only Auto Trak 2.

The 1990 to 1998 t-cases take regular old Dexron 3 - same as the tranny. These don't require as many flushes but it is good maintenance anyways.

The flush procedure is the same for both. You loosen BOTH plugs first! (To make sure the fill will come out) Then remove the bottom plug and catch the fluid. Once it drains out, reinstall the plug and remove the upper one and add 2 quarts (liters) to the bottom of the upper hole.

Ok, jist a drain 'n fill, v.s. a 'flush' 'n fill.

Thanks.

I did just like Lifted said and it cured my binding problem right away. The Autotrak II fluid was cheaper at Lordco than it was from the dealer.

LiftedAWDAstro wrote:The 1999 and newer must be done every 30,000 miles or you risk having weird driving issues with binding or surging while accelerating. The These newer t-case take the GM only Auto Trak 2.

The 1990 to 1998 t-cases take regular old Dexron 3 - same as the tranny. These don't require as many flushes but it is good maintenance anyways.

The flush procedure is the same for both. You loosen BOTH plugs first! (To make sure the fill will come out) Then remove the bottom plug and catch the fluid. Once it drains out, reinstall the plug and remove the upper one and add 2 quarts (liters) to the bottom of the upper hole.

Oh God Bless your Dean. My heart jumped when I started to read this thread because I have been draining and filling mine every YEAR and not use GM fluids (now using Royal Purple) so I thought I might have been damaging my ride but not knowing. Good to do it - brings back the nice smooth coasting and mpg (I notice it and so does the Scangauge) as well if you like rhomping on the AWD I think it is good to treat her well eh?