Fluid changes
 

Hi guys, I'm going to be servicing my '89 300CE in the next couple of weeks to get it ready for winter. I'm going to be changing the transmission fluid and filter but have a few questions. Firstly, how can I get most of the fluid out? I believe there is a drain on the torque converter, correct?

Do many of you run synthetic fluid in your older Mercedes' transmission without any problems? If so, what brands do you recommend? I'm also thinking of going with a thinner grade of oil, possibly a 5W-40 Rotella as opposed to the 15W-40 that is in the car now. How does the M103 take the thinner weights? I have had the top end and head gasket replaced so I'm not concerned with oil leaks, at least not yet...

There is a drain plug on the pan and there are several in the torque converter. Just turn the engine SAFELY until one of the torque converter drain plugs is at the bottom. Drain the pan and the torque converter and refill. Make SURE that you get the correct reading on the stick under the CORRECT temperature conditions.

Especially in your climate, there is no need for synthetic ATF IMHO. The 5W 40 might be a good choice for your climate. The M103 has sliding cam followers as opposed to flat tappet, so it might not be necessary to run the Fleet type oil in the engine. I like the added detergents for keeping it clean, and with a flat tappet engine the zinc additive to some level is necessary, but in your situation I would think that a good 5W30 would get the job done.

My $0.02,

I will go with the regular ATF fluid then. It is Dexron III, correct? What intervals should the fluid and filter be done at? Would every 15k miles be too soon? I'm also thinking of changing out the PS fluid. I believe I can only use the dealer only stuff if I'm not mistaken. I also need to think about possibly changing the battery. Are the OEM Mercedes batteries really worth the extra cost over an aftermarket replacement?

Just put in synthetic and quit worrying forever about "thick" and "thin."