1999 SL600 -- ATF leak
 

Hi guys. I just bought my 1999 SL600 yesterday. It has 103k miles and has just had the transmission replaced with a unit from an '02 car due to planetary gear failure on the original. He only put 2500 miles on it in the last two years, so I'll probably be looking at a fair share of seals to replace pretty soon.

I drove it home (350 miles) with no problems. This morning, there were no leaks under the car. I drove it an additional ~20 miles and parked it in the garage. I started cleaning up some scratches and stuff and then took it out, only to notice a small puddle of red fluid... the infamous 722.6 fluid. It's coming between the trans and drive shaft. I've attached pictures. Any idea how much this costs, and is it DIY?

Thanks.

Rear seal....not really that hard to replace all things considered. It is potential DIY IF AND ONLY IF you know what you are doing. Otherwise a shop needs to do it....probably about 3ish hours of labor is my guess....maybe 4, depends on what they have to remove to get at the tail piece of the trans.

Ok, is there a guide I can take a look at it? My father and I are alright mechanically, and can figure stuff out with relative ease.

There's not really a guide.....but for starters you'd need to remove the:

-exhaust
-driveshaft
-rear output yoke on the transmission
-support crossmember and support mount
-rear tail piece
fluid would need to be drained....etc....

It'd be a pretty involved project.

All of the trans fluid needs to be drained? It's brand new fluid. Is it just an age issue that makes it the seal go bad? I don't understand why this seal wasn't replaced as part of the trans replacement job.

This doesn't sound like a cheap fix.

It is a cheap fix....if...you do it yourself. Previous poster with the instructions is spot on.....but..it took me 6~7 hours vs paying the stealership a grand!
I have issues with shops and stealerships charging unreasonable rates and yet paying the actual person doing the work slave wages! Sure, one needs to make money to stay in business...but screwing over folks is uncalled for. Stealership rates are what...averaging 100 bucks an hour...independent shops what...50/60 an hour. Unreasonable.
Just because one owns a Benz does not mean they can afford it!
Here on Guam...shops charge 50/60/70 an hour and pay mechanics 10/12 bucks an hour! And when you pay and leave...another problem pops up!

I see. I got a quote for around $250 - $300, trying to talk him down to $200 flat for repeated business and such. Not bad, I guess... could have done without it though.

The mechanic also mentioned that if the bushing on the transmission is bad (drive shaft wobbles), it will need to go to a transmission shop... any insight on this? How would I tell, besides getting under the car to inspect play in the shaft?

The leak has developed much, much more at this point... it's leaking quite a bit of fluid. The fluid is a slightly different shade than pure pink Mercedes ATF... normal?

Is this seal the only one in this particular section of the car, or could I be looking at another problem?

It is not the rear seal, as I thought. I got under the car today to inspect the drive shaft and flex joints and they both are tight and look fine. There appears to be a 3-4" long connector that has a piece of rubber surrounding it that is the cause of leak. It plugs into the transmission on the driver side. Can anyone tell me if this component just needs to be adjusted or replaced? If so, how much would it cost? I'm guessing that the whole line won't need to be replaced... it looks like it could just be unplugged and fixed accordingly.

Front electrical connector leak is VERY common on 722.6 (5-speed).

The parts are about $20.

It's only the "driver side," however, if you live in the UK or somewhere else with RHD.

I think what is leaking is the shift boot interlock. It is near the flex disk.