I use formula+ in the tranny, but the dealers really push the 20W-50 motor oil for in the tranny. I am not really sure why, you would run a engine oil in the tranny rather then a tranny lube like formula+.

 

Syn 3 in all three for over 100,000 miles,still rocking.

 

I had a severe clutch grab until I switched to Mobil 1 in the primary. Smooth as butter now.
Gary D.

 

At the 1k service I put Mobil 1 VT 20-50 in engine and primary and Redline Severe in the tranny. Changed engine oil at 6K, still Mobil 1 VT 20-50. Now have 9500 miles and will change all 3 holes at 10K as above. Runs great and no strange noises of any kind!

 

I had Mobil1 VTwin 20w-50 in all 3 holes, had no problems.

Did a 5000 mi service today, now I have
Engine M1 Vtwin 20w-50
Tranny M1 75w-90
Primary Syn 3 (had a quart layin around, wanted to use it up)