I decided to change the transfer box oil today (only had the 80 for two weeks) it was filled with the same oil as in the auto box, red and quite thin, I have now put in API GL5 80/90 gear oil which is what I have also put in the diffs, has anyone else noticed that they have had auto box oil in their transfer box?
Interesting-using ATF instead of gear oil was a significant mistake by the previous owner. Many domestic 4x4's use ATF in the transfer case so it's easy to understand the mistake. Toyota specifies 75W-90 gear oil in the transfer case, I've always used the Mobil1 75W-90 in that application.
I hope it has not done any damage to the transfer box? It did look like new oil and no iron filings on the magnetic sump plug. I must admit, the box sounds a little quieter when you move the drive shaft back and forth, have not taken it out on the road, as I am waiting for the firf seals to arrive, I had to do a full service on the passenger side (UK) as I had the dreaded two stud shear off on the lower steering arm/knuckle, phew!!! it was close.
