Well, after months of thinking and researching, I finally drained and refilled my MTL to Mobil 1 Synthetic (75W90) at roughly 17,000 miles. I had read some of the horror stories here about people having tranny problems after the swap. However, after searching a couple auto parts stores, M1 was ONLY 75W90 gear oil I could find.
Procedure: I followed the procedure from Scoobymods (
http://scoobymods.com/forums/showthr...?threadid=1743), and it went smoothly. The old oil DOES stink REALLY bad, my garage still has the odor. Also, using a flexible funnel is highly recommended. I used a long neck stiff funnel, and ended up spilling some lube

. Also, I found that I had to squeeze the bottle slowly, because the dipstick hole couldn't handle too much oil at one time.
Results: Before the swap, my transmission was fine - no problems, felt smooth and so on. I wasn't expecting much from the Mobil 1, but now the shifting
is noticeably slicker and smoother. Hard to explain, but things just feel more lubricated inside the gearbox. No side effects - no grinding or weird sounds yet.
edit: corrected speeling error