Engine/Transmission (1998.5 - 2002) Mixing Dino and Synthetic gear lube

[Pit Bull]

I'm going to suction out the gear lube in my Dana 80 which is dino factory lube and replace what I suction out with either Mobil 1, or Royal Purple synthetic gear lube. I am aware that I won't get all of the factory dino gear lube out with this method. Will it cause any problem mixing the new synthetic with the old dino gear lube? I only have 50K miles on my truck and it is a daily driver. Based on schle "A" I never need to change the gear lube. Please don't lecture me about doing it the right way and taking off the cover and cleaning everything out. I plan on doing that at 80K miles. Will this interm suction method hurt anything or might it help?

Thanks for your input.

 

[LSMITH]

Won't hurt a thing, and ALL of us that have synthetic in mixed oils. You cannot get all of it out no matter what short of disassembling the entire rear end. Just suck it out and pour the new stuff in. Pull the cover and clean the magnet next time