This is for my 82 240d.

So this weekend my buddy and I took on the task of changing the engine oil, manual transmission oil, and differential oil.

I got 75-90 synthetic gear oil for the differential.

I got Royal Purple Synchromax for the manual transmission.

Completed the manual transmission change, filled with the Royal Purple. Came in the same looking bottle that the 75-90 gear oil came in. I added about 95% of the gear oil in, and some dripped on my face. So I had to get up and wash it off. While I was in the house, my buddy was adding what was left of the royal purple into the differential. Thought it was the gear oil.

So basically, there is about 95% 75-90 synthetic gear oil in the differential, with a very small, about 5%, of the royal purple. I do not know what weight the royal purple Synchromax fluid is.

Will this do any harm?

Thanks.