I recently took on the ambitious task of taking care of a lot of the little issues that were adding up on my wife's '04 MCS (Dealership quoted $3000+ for repairs ), so I dropped a few hundred dollars on parts and did the following things:
New Oil Pan Gasket (with oil change, filter, & Quick Drain Plug)
Manual Transmission Fluid change (75w/80 GL4 from dealership)
New Power Steering Hoses (not the high pressure one though)
New Passenger Side Inner CV Boot, Grease, & Clamps
New Control Arm Bushings & Brackets
New Inner Lower Control Arm Ball Joints
New Front Outer Ball Joints
' & Other little odds and ends

Please understand, this was a bit more than I've done, but I just couldn't pay that much in labor, so I figured it out… mostly.

I systematically followed the shop manual and various forum posts, and all went pretty well… slow, but good. I got it mostly buttoned up except for the front wheels, still had it on all four jack stands, and thought to myself, "Maybe I should fire this baby up, see how it sounds, and check for any leaks.". So, after starting, and the oil had a chance to bath everything, it purred like a kitten. Next, I started rotating the steering wheel slowly from left to right and back again several times in order to bleed any air out of the power steering lines… again, no problem.

Next, I thought I'd try putting it into 1st gear to test the smoothness of the new transmission fluid, and that's when it made a weird noise, which come to find out was the DSC kicking in (flashing DSC light included). I also noticed a small amount of transmission fluid leaking out around the passenger side of the transmission housing where the axle enters into the housing. In my repairs, I did not want to pull the entire axle assembly out of the transmission, and I was able to separate the axle at the CV joint to deal with the torn boot. I am pretty confident the leak may have been there before my repairs, but nonetheless, there's a leak.

So, is it normal for the DSC to kick on when it's still in the air?
Should I slap the wheels on it, drop her on the ground, and try driving it?
How serious is this leak (can it wait another month or two)?

Thanks ahead of time for all of your wisdom!

 

Yes that is complete normal for DCS to come on while the car is in the air. it "thinks" the car is slipping... front wheels are spinning yet rears are still. flick the dsc button off and it will act normal.

maybe its just a bad axle seal... or you did not push the axle in far enough.. depends on how bad the leak is but i would not wait. running a transmission dry is not so good and getting another one is a pain. its just like running a engine dry.

 

Well, all seems to be running well. I took it for a 30 minute drive and it handled like a champ. I put a big white poster board under the car when I parked it in the garage, and no leaks! The transmission fluid leak was minimal while it was in the air and wheels were dangling, but once on the ground, it disappeared.

Thanks!