Failure of In-Rad Trans Cooler

There is a Subaru Outback near me that is for sale cheap. Current Owner says they think the in-radiator transmission cooler failed. The car was in their driveway and it started puking a mixture of coolant and what does appear to be transmission fluid. They shut it off quick and haven't re-started the car.

From my research, it appears that the transmission operating pressure is greater than the coolant system pressure, so that seams to be a reasonable explanation. Any comments?

I have seen the car and looked at all the fluids. No real sign of any coolant in the transmission fluid.

I am thinking get the car cheap and fix-n-flip for additional funds in my rally-car fund. Would need a coolant flush, a new rad, plus all the fluids replaced.

Downside is that if the trans is hurt, it's a 5EAT and they are not cheap even from a recycler. I wasn't really looking for something that I have to pull the engine and trans to fix either.

On another note - anyone have any experience with Subaru 6-cyl? This is a 3.0 EZ30D (late - 05). I have done some research and they appear to be a decent engine. They use a timing chain instead of a belt.

Are they sure it's not oil? That would indicate a head gasket.

jstein77 wrote: Are they sure it's not oil? That would indicate a head gasket.

I looked and it definitely has red colour to it, so I am pretty sure it's ATF.

Will they allow you to pull the Tranny filter before purchase? It's external screw on filter so it's not too hard to get to. That could tell you if the coolant made it to the transmission or not. It's not an uncommon failure.

If the price is right, roll the dice. You should be able to part it out and get your money back.

I had this happen to me. It sucked coolant back in the return line while pumping trans fluid into radiator. It killed the trans in a couple minutes limping home and oveaheated the engine. I knew when temps were climbing fast and trans was slipping it was toast so i limped it home(2 miles). Complete drivetrain destruction. Scrapped the vehicle.

I would offer based on needing engine/trans

Water or coolant in an auto trans is pretty much immediate death for the trans. The clutch material tends to de-laminate very quickly.

Engine is probably fine provided it didn't overheat significantly, it'll just need a thorough cleaning of the cooling system.

I've no experience with that particular car but I've replaced a bunch of radiators that failed that way and the few that I've seen with transmission damage were run hot and showed signs of coolant on the transmission dipstick.

Certain nissans are notorious for this... trans usually dies pretty quickly once coolant gets in there.

There is a certain brand of forklift that shall remain nameless, (cough, N****n, cough), that had a bad batch of radiators with this failure mode.

The ones that were cought early, before coolant got sucked back into the trans, did just fine, aside from a permanent oil sheen in the top tank of the radiator.

The ones that were not cought early all needed trans overhauls.

Common failure on G35/37 auto equipped cars. Coolant ends up contaminating the transfluid and killing the Trans control module/computer.

EDIT: as someone else said, it's also common on nissans. Namely the 5 speed auto equipped ones.

If coolant got into the ATF the fluid on the dipstick will look kinda like Pepto Bismol/cheap strawberry milkshake. Could this be one of those cars that came with red coolant from the factory?

I've seen quite a few late model Volvos do this. I'd say 2/3 drive away after a serious transmission flush and radiator replacement.