99 C280 Transmission

[nhmercracer]

Change your ATF, or this is in your future. Not my first transmission failure, but TH400 is MUCH easier (and cheaper) to R/R than the 722.6

Just so all can see my pain.

http://www.mcarterbrown.com/gallery/data/500/Tranny_011.JPG (http://www.mcarterbrown.com/gallery/showphoto.php?photo=27671&title=tranny-011&cat=500)

http://www.mcarterbrown.com/gallery/data/500/Tranny_009.JPG (http://www.mcarterbrown.com/gallery/showphoto.php?photo=27669&title=tranny-009&cat=500)

http://www.mcarterbrown.com/gallery/data/500/Tranny_007.JPG (http://www.mcarterbrown.com/gallery/showphoto.php?photo=27649&title=tranny-007&cat=500)

http://www.mcarterbrown.com/gallery/data/500/medium/IMG_2206.JPG

http://www.mcarterbrown.com/gallery/data/500/Tranny_012.JPG (http://www.mcarterbrown.com/gallery/showphoto.php?photo=27750&title=tranny-012&cat=500)

[Sulaco]

Yikes.

My dumbass has now logged about 200,000 on a rebuilt transmission with no flushes. I was always operating under the widely accepted misconception that our trannies were the kind you're not supposed to flush.

I've been dealing with a MASSIVE flare between third and fourth for years now, though I think that problem is largely vacuum related. Nowadays it gets to where it's starting to slip, but due to leaking fluid. I have to keep a funnel and some dex 3 in the trunk to keep it topped off. I'm not even entirely sure where the leak is, but I'm starting to believe it's on the cooler line.

Luckily I've got a spare in my parts car, too!

[JRE320]

I don't have any problem with my rebuilt transmission. it got 50K miles already.

[eundaddy]

are you fixing that tranny or buying a rebuilt one? if you are rebuilding it, you should post some more pics of your progress!

[nhmercracer]

I wish I had taken pictures of the dis-assembly. The 722.6 is very impressive internally. The gear-sets and clutches are plenty large. My transmission failed due to the input/output shaft bushing (K2 clutch drum) failure. This bushing separates the input and output shafts, allowing them to turn at different rpm. When this bushing fails, it allows one of the thrust bearings (pictures 4 + 5) to become unevenly loaded, and starved for fluid. This situation coupled with worn out transmission fluid (which is a poor lubricant), causes this bearing to overheat and fail. The pieces in the last picture have actually traveled through the center planetary gear-set, destroying it in the process. This transmission was destroyed, and it was not financially feasible to repair it. The needed parts would have cost more than the car is worth. I finally purchased a used unit with very low miles to replace it.

The reason I suggest new fluid it to prolong the life of the bushing and thrust bearing. Once the thrust bearing fails, the transmission is done for. Replacement parts are profoundly expensive, even at cost.

Eun, I PM'd you on BW

[Sulaco]

I'd give real money to have a complete understanding of how the innads of the transmission works. I can DIY damn near anything on my car except body work and the transmission. I'm going to be completely honest here, I have absolutely no clue how an automatic transmission works. i've always secretly believed it was a combination of voodoo magic and unicorn poop.

[eundaddy]

i think its 90% unicorn poop and 10% voodoo magic.