[Chevthepup3101]

OK so this is gonna be a while let me start at the beginning. About six months ago I ran over an 18 wheelers tire tread that came off which broke something I didn't know at the time so I pulled over and shut the car off immediately. There was a pile of what looked like oil under the car and I thought I had broke the oil pan. I got it towed back to my mechanic who said it was seized so I put it in my driveway and left it for six months to work on my other projects. I finally got the time to see what was wrong with it and to my surprise after ripping the front of the car off the motor wasn't seized. I also drained the oil and seen the full amount of oil came out and in good health. The fluid that was on the ground was transmission fluid from a hole that have been punctured on the transmission cooler I'll include a picture below. But after taking off my radiator I figured out that the coolant was mixed with something else which darkened the coolant and made it a little bit thicker i'll also include pictures of that. I ordered a new radiator all new fluids and a new transmission cooler I'm gonna flush everything out and replace the broken parts but I'm confused as to why the coolant is a dark color and not a light pink indicating transmission fluid mixed with coolant. It's as if it blew a head gasket but the oil that I drained out of the car from the oil pan was perfectly clean. The two of pictures I added below are the transmission cooler with the crack and the coolant I drained out of the radiator

[mainbearing]

Don't BMWs use either blue or the new HT12 green coolant? Maybe someone mixed different coolants in there?

You can test the old ATF cooler and see if the ATF circuit is breached. I would be more concerned about the transmission if coolant got in there (likely to kill the clutch packs), than ATF getting into the cooling system.