Coolant mixed in Trans fluid!

[Revival]

I think I know the answer to this one already but wanted to get a sanity check. Ex Toyota Pro tech here, but 15 years out of the business. I have forgotten much.

Vehicle: 1999 4Runner Limited 4WD, Auto transmission, 160,000 mi.

I was on a short trip to the store when I noticed the trans shifting hard. Within just a few minutes I overheated and pulled over to find transmission fluid and coolant pouring from the top of the transmission. The radiator was empty and when filled, there is trans fluid there also.

Expectation: The trans cooler lines have failed within the radiator. The overheating caused the coolant pressure to force coolant back into the trans. Sound right?

My plan unless someone has any other recommendations:
1) Replace the radiator and flush thoroughly.
2) Drain and refill transmission. Immediately take to trans shop for full flush and filter change in hopes of saving transmission.

Please voice your opinions. I need to drive this truck a bit longer if possible but will consider a trade in if you think I'm headed for a new transmission regardless of what I do.

[Revival]

Does a MOD want to move this to the 4Runner section? lots of "0" replies here... Just looking for active Technicians to give me a sanity check that I am on the right path.

[Pineapple]

I agree with you. There is no other way to get coolant in tranny. Unless someone fill it with coolant

[titleist]

this is very common with four runners. replace the rad and flush the fluids until the "pepto bismol" is gone.

[Revival]

Originally Posted by titleist

this is very common with four runners. replace the rad and flush the fluids until the "pepto bismol" is gone.

Thanks,
Still in a bit of the "pepto" phase but only very minor. And also chasing trans fluid out of the cooling system. On the last test drive it is shifting a tad hard from 1st to 2nd, but otherwise good. I will change the trans fluid a few more times.

[speedy25]

Be sure to flush your engine too. Oil makes a great insulator in a water cooled system and your cooling efficiency will be poor until you get all the oil flushed out.

-SP