Transmission fluid inside differential

Are there any gear lubes that are red in color? Maybe Redline synthetic or ??? Someone installed the wrong fluid. Or you have an internal leak inside of your trans.

How does the trans function? Are you losing any ATF?

Where do you live? I is not an uncommon trick to use transmission fluid in them in very cold areas. No need today with synthetic lubes available, but I can remember when it was common.

Transmission is okey. I am losing ATF, but slowly. But, it could be that I put too much ATF, and it just overflowed to differential. I do tend to overfill both engine oil and transmission fluid.

I just sucked (using hand pump) as much of that ATF/gear oil mixture as possible from the differential, and put 0.5mL of 80w90 gear oil. I'm hoping that regular flush of differential is good enough.

This begs the question. If ATF is going into differential, then can consequent ATF/gear oil mixture go back into transmission? Does this mean replacing ATF as well?

So if you are only losing a little ATF over time, are you also noticing a change in color of the ATF? Maybe the ATF is fine, but maybe some internal seals are allowing the ATF to go over into the diff. I would say drain and refill the diff and keep checking it over time.

later, dave (One out of many daves)

The red color seems a bit faded. Not sure whether it's from being naturally old fluid or from mixing iwth gear oil.

I replaced ATF also. And, will keep ATF closely monitored. Thanks.