So I want to switch to Synthetic on my 93 945 Turbo. The car has 203k miles on it. What should I go with? Mobil 1? Also, how many quarts should I get??
Thanks for your help!!!!

Chris
unibagel@yahoo.com

Hi Chris,

Both of my 745s have Amsoil 80W90 (~2 quarts) in their rear diffs (both lockers). Seems to work well in both of the cars. I don't really notice much of a difference, maybe a little smoother when locking and a little quieter. I imagine it'll be good for the diffs in the long run too :) Hopefully it improved fuel economy a bit too, but I didn't really do a mileage comparison, so I don't know. My 745 turbo has Amsoil 10W40 in the engine as well. Great for turbo engines and the turbos themselves love it. Also, I usually use Mobil 1 ATF in the power steering and that does wonders for a tired steering rack. I haven't tried Amsoil ATF yet.
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Chris. Halifax N.S. '91 745Ti, 290K km and '91 745 NA, 380K km.

Chris,

I've run Mobile 1 75w-90 synthetic gear oil in all my Brick's read ends with very good results. Also Mobile 1 ATF in the auto box and Power Steering with Mobile 1 10w30 in the engine. All good products I'd recommend. The diff holds 1.7 quarts of gear oil ... I've found using one of those screw into the top of the bottle pumps very handy for filling diffs/trannys.