ATF in coolant - need advice
 

So I take one of my '88 300 SEL's in for an ATF change and when I go to pick it up, he says there was a lot of "condensation" in the old fluid and they weren't sure if it was water or coolant. Next stop - radiator specialist who says yep that's ATF in the coolant reservoir.

So I take it over to my local indy who looks up a new radiator, $200 for a Behr, sounds good... but then he starts talking about needing to replace the thermostat and hoses --- "ATF can really chew those hoses up and the thermostat gets all gummed up" --- even though I just replaced all that a couple months ago when doing the water pump.

So is it really necessary to replace that stuff even though it's all new and it's going to be flushed with some kind of a cleaner to get the ATF out?

Also, would I be advised to change out the ATF again even if the car has only gone about 15 miles since the ATF change for fear of the coolant contaminating it again?

coolant in transmission
 

My experience has been that the coolant in the transmission swells the clutch plates and destroys them very quickly. If after flushing the transmission, by draining the transmission and the torque converter several times, the transmission shifts hard or slips, it will be time to rebuild. Hope you get a better answer from the MB guys, but that's my experience with a ruptured AT cooler inside a radiator on a Suburban.

Gary

Gary is right. Don't drive any more than absolutely necessary and try multiple complete drains and refills.

Regarding the hoses and the T-stat, I would at least do the T-stat and the radiator (which caused the problem in the first place).

Haasman

Thanks for the replies guys, I figured the transmission would need to be cleaned out well after this incident... if only I had replaced the radiator back when I did the water pump :(

Speaking of radiators, and not to change the subject, there was a segment this week on the Science Channel show 'How It's Made' about the radiator manufacturning process. It showed how copper and brass radiators were made, not the current aluminum and plastic ones.

Back on the main topic, plastic and aluminum radiators might really be a disposable item at 100K miles.

Glycol in trans
 

The dealers have a glycol test kit for contaminated trans fluid. I saw such a disaster in progress a few weeks ago at my dealer. The culprit was the Valeo-made (Italian) radiator in a C32. The trans cooler and radiator were cross-pollinating and the ATF contamination was beyond the allowable limit. Luckily for the car owner the warranty was picking up the radiator and transmission replacements. The tech said this failure was being seen more often.