Leaking SVX/ Synthetic Oil

Anyone have the part number for the seals that have to be replaced on my SVX? Anyone do this work themselves?

1. Front Crank Seals (Dealer wants $490.00 to replace)
2. Front Side Differential Crank Seals (Dealer wants 250.00 to replace)
3. Both Belts (Dealer wants 85.00 to replace)

Of course the $ does not include parts!

Could this be from using a different oil (MOBIL 1 SNY)? I started using MOBIL 1 SYN oil about 3 months ago? I have done 1 oil change ever since. Now why am I getting leaky seals all of a sudden?