95 850T, Transmission issue, like it's in neutral, flashing arrow and CEL

[dosbricks]

OK, my wife and I have owned our cars for 18 years, and I flush the trans on both about every 40-50k and both working smooth with nice clean fluid in there. Check the mileage in my sig.

[cn90]

It's not idea or myth...it's reality!
I have friends which had that exact experience on Grand Cherokee,Audi,Mercedes.

Also have a friend who owns Mercedes service shop and he refuse to change oil in auto transmission.He would do that ONLY on full owner's responsibillity.

One friend changed transmission oil on Grand Cherokee on his own responsibility and transmission broke few km away from the shop.It was working normally before fluid replacement.A lots of examples besides that Cherokee.

Every time I see these comments, I just laugh b/c I have changed ATF for 30 years, not a single problems.
From a "scientific" stand point, an ATF change brings in new fluid with better spec viscosity and bringing the fluid back to spec, and that is about it.
How can it damage the trans? Making the clutch pack slip more?
I am not talking about "flushing machine" which is a different ball game.

[mecheng]

Because the transmission is a fluid coupling, a fluid change would help in this case, especially considering his fluid is black. The sludge which is usually metallic based is caught by the magnetic drain plug, you clean the plug allowing it to trap more metallic debris and you remove the contamination from the system. All good things and worth a shot, before you declare it RIP. It is well known in the auto industry, lifetime fluid is a marketing tactic and is good enough for the fluid to last 200,000km which is all the mfg cares about the car to last for.

[bmdubya1198]

Because the transmission is a fluid coupling, a fluid change would help in this case, especially considering his fluid is black. The sludge which is usually metallic based is caught by the magnetic drain plug, you clean the plug allowing it to trap more metallic debris and you remove the contamination from the system. All good things and worth a shot, before you declare it RIP. It is well known in the auto industry, lifetime fluid is a marketing tactic and is good enough for the fluid to last 200,000km which is all the mfg cares about the car to last for.

Lifetime fluid is the biggest crock of s*** I've ever heard. I'm wary to flush my transmission, still, but I might actually try it. Maybe before my possible manual swap just to be safe . My car shifts very nice and smooth, and the fluid looks and smells fine, which is why I'd rather not mess with it now.

[iruleyounow]

I'd like to throw an update on here. I sent the car to a friend in Chicago. He's a master mechanic and he's had the car for about 2 months now (pretty busy). The transmission fluid was like sludge he said. Apparently somewhere along the way someone put the wrong fluid in it and it didn't mix well with the recommended fluid. He performed 4 drain and fills and has been driving the car non stop for about 2 days and has not encountered one issue. All gears are shifting great and the car is performing as it should with no CEL. I'm obviously extremely happy that the transmission is okay. He said the long road trip I took caused everything to heat up and clog and just not get good circulation through the trans. I know this Is partly my fault because I totally spaced changing the trans fluid. I've had the car for 2 years and only put 1500 miles on it, so It wasn't a huge concern at the time. Just thought people would want to know. I pick up the car this weekend!

[bmdubya1198]

Glad to hear it's fixed! I'm surprised just replacing the fluid fixed it, and the sludge didn't mess anything up. These older 4 speeds are pretty tough!