car has 245K miles on it and I want to go to RedLine synthetic trans fluid (or something better, any suggestions??). The trans also leaks a bit of fluid. Main reason for change is age of trans and it slips a little, and hesitates sometimes. SO, a couple of questions- who has done this, is it recommended/beneficial? And if so, any tips/tricks to actually changing it myself? Tools? New filter? Any suggestions are welcomed. TIA
Mark

If you have a slightly leaky transmission, then I wouldn't use synthetic in it. The reason is that synthetic is a 'thinner' oil, and will more than likely make your leaks worse. I would simply use a good dino trans fluid.
Also, if you don't know when the fluid was last changed, I have heard that you should change it and drive it for 1 or 2 thousand miles, and then change it again, because this will dislodge all of the sludge and so on. Good luck.

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2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

I could be incorrect here, but I believe the stories on synthetics making leaks worse is from the days of Mobil 1 0w-30. Now that they have more "conventional" multiweights, the problems don't occur as often...

For changing the transmission fluid... Not a big deal at all. Get a kit from Partshop. Wait for it to arrive... Then do a search here to get info, it's been done before. You MUST drain the torque converter, so I start there (if you can't get that to work, you are out of luck...). Really it's the only pain. The biggest thing to remember is to be absolutely meticulous - keep ALL foreign matter out of the pan.

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Bill Streep
San Antonio
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)

BE SUPER CAREFUL WHEN PUTTING THE TRANS PAN BACK!!!

Torque specs are in INCH-POUNDS, NOT foot-pounds. VERY little torque is used on these bolts. I went through this with my wife's 190E about 6 months ago but didn't have the correct torque spec / wrench. I over-torqued the bolts and it ended up puking all of the Mobil-1 ATF on the ground in the parking lot at my wife's office (53 miles from home, one way!).
Thank God for AAA-Plus (100 mile towing - on a flatbed in this case!). My regular shop just dropped the pan, put in a new filter and filled 'er up (using conventional ATF). I was grateful that it didn't cost me $2500-3000 for a rebuilt trans and labor.

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Jay Yambrovich
Scotts Valley, CA.

1993 300 CE Cabriolet (A124) 131K miles
1997 C-280 133K miles

2000 BMW R1100RT 69K miles
1989 300 E 216K miles (sold)