2006 Chevy Trailblazer SS, RPM Level V GM-4L70e, PTC converter, ~ 2900 RPM stall, B&M 70274 SuperCooler (bypassing the horrible radiator cooler entirely - that breached twice and killed 2 transmissions and a number of engine cooling parts). This is the 4th transmission and 2nd cooler. Has about 20k miles on it (88k on the truck total). Was shifting horribly, whining, slipping, making a sound like a lug nut tossed in a blender occasionally. The fluid looked like watered down Yoo-hoo and smelled like bad, bad things had been happening to the friction material.
Tossed in a bottle of Lubegard flush from the 98602 Flush and Protect pack. Truck up on jackstands, ran it through the gears to simulate the instructions on the flush.
Took apart all cooler lines and cooler (the factory lines meet up with braided stainless which then run to the cooler). Flushed all lines and cooler both ways with 2 bottles Lubegard 19001 Dr. Tranny Kooler Kleen. Blew dry with compressed air.
Reassembled, except for cooler line at inlet of cooler, pumped out mocha brown fluid, periodically adding Dexron VI (I had 12 quarts of Havoline Dexron VI, 6 quarts of Mag 1 Dexron VI, 4 quarts of SuperTech Dexron VI, and one almost full jug of GM Dexron VI). I went through this pump and fill for about 18 quarts, until the fluid looked perfect and when I ran some through my Mr. Tea filters I didn't see lots of clutch material. Then I added the Lubegard protectant.
Drove truck around the block. Slipped badly. Checked fluid, it was low, added quart and a half. Slipping pretty much gone, I could make it up the driveway, anyway.
Drained fluid from transmission (I have a drain plug), dropped and cleaned pan that looked like someone filed down horse hooves in it, and replaced filter and gasket with AC Delco replacements. The filter screen in the old filter was a bulged out piece that looked solid (as in plugged), so I'm guessing a lot of fluid starvation might have been occuring.
Added 1/3 of another bottle of Lubegard along with about 5 quarts more Dex VI. It's a funny transmission - fluid takes a while to level out - I use cheap $5 Harbor Freight transfer pumps to lower fluid levels every now and then.
Drives much better, still misses the 2-3 shift under heavy throttle (3-4 piston seal failure, perhaps, the 3-4 pack is probably the bulk of the friction material in the pan), but the 1-2 shifts spin the tires easily again, and off the line if you're near the stall it really is a handful to hook up sometimes, so that's all good.
I'll probably do the same thing again in 6 months to see if I can't get along until the next tranny, which I believe I might rebuild myself - seems like a good thing to know for someone like me.
Funny, our Lexus RX330 (113k miles) is much easier to maintain.
