Synthetic ATF: Is there downside, what is upside?
 

Car has 178,000 miles, has always had regular ATF. Considering switching to synthetic. I don't care about smoother shifting (though I might like it if it was a result); main goal would be extending life of transmission.

Would this likely be the case?

And, as long as torque converter is drained too, is there any downside? My last tech strongly advised against switching, saying it could create problems. I have no desire to invite unnecessary problems, but I want to take the best possible care of the original transmission.

(I know there are some scattered posts on this...I've read them...but would like some more extensive input.)

Thanks!

I switched to full synthetic ATF (Amsoil) 10,000 miles ago. No problems so far!
Colin:)

What I noticed switching to Mobil 1 ATF in an 87 SDL with 260K miles is that the transmission doesn't feel different before the fluid gets to operating temp. I can't describe the difference but it's not there anymore or there's much less difference now.

Sixto

I've noticed the same thing: transmission in the 190e 2.6 shifts more smoothly cold and is overall more responsive, hot or cold. I am using Mobile Synthetic ATF.

BTW, I am trying moving back to all Mercedes fluids: ATF, coolant, powersteering etc. I am surious as to whether there really is a discernable difference. I'll post after all the fluids are changed.

For oil, I am doing a 15W-40 fill at the next change to see how much the engine and most specifically, the hydraulic lifters, clean up.

I think overall, the synthetics are good. With the engine oil, synthetics clean quite well and where sometimes a leak has started but isn't noticeable, the synthetic will advance the leak, such as with upper cam covers on 103 engines. I have seen the results of running synthetic differential oils- the insides are very, very clean. Synthetics also help in reducing worn differential whine.

Haasman

Well...

When I went to my dealer for ATF for my 95 E420, I got Quaker State Dexron III(H) in green bottles.

It wouldn't matter which MB dealer I went to in Canada - it's what they all use!

It's always worth checking with the dealer for this stuff, though - their price to me was cheaper than the jobber I was using, and the stock was fresher - the jobber didn't have H-spec fluid on the shelf.

Cheers
JJ

To be more specific, is there a danger that, after switching to synthetic, debris will be loosened and leaks will emerge that would not occur if I stick with regular ATF? I should add that the fluid and filter have been changed every 30,000 miles (it now has 178,000) and, the last time it was changed, the tech commented on how good/clean things looked.

danger
 

the mobil one works great in the tranny but dont put it in the power steering..
it ruins it.... causes leaks and such... just stick to ps fluid.... i put it in the power steering... and i have cause some trouble..