Not sure what you mean. "Drive oil" is simply gear lube. Merc just supposedly adds some extra water emulsifiers for protection in case of a water leak into the drive. Any of them leaking into the water is not good for the environment.

Truck = Amsoil 10W30; also Amsoil in the tranny and differential

Boat = Amsoil Series 2000 20W50 Severe Service Racing Oil; Series 2000 75W-90 Gear Oil in the outdrive

Two reasons:

(1) There is only one true synthetic oil out there that offers straight weight oils w/ detergent in 30W or 40W (Royal Purple). Redline's 30 & 40 are non-detergent for racing only (to be changed after EVERY race).

(2) The reason Merc does not recommend the multi-weight oils is that conventional dino oils require additivies to make them multi-weight. Syn oils require very little or no such additivies unless you are using an oil with a large "spread" such as 5W-50.

That said, from what I've heard, the straight-weight blend that Merc has is the best idea of all (except that it is not synthetic). It's like having multiple sizes of ball-bearings. If somebody make this oil in a syn version, I'd be all over it. What I don't know is if creating this "blend" is as simple as pouring two different straight-wt oils into the same container. I would guess not as it seems like the heavy stuff would always go to the bottom.

Kendall Racing 20/50. Change it every 10-15 hrs. Just did a rebuild and am told everything looks perfect. No major parts needed.

I have a stock 454 Mag MPI with 500hrs. I use the merc motor and gear oil. No problems, and I drive it like I stole it!

Valvoline VR1 40

royal purple for me.....

KY Jelly has never let me down :D
aborbs any water you may have in your motor too

works grear in the drive too

A favorite for years KY Jelly by Johnson & Johnson is the No.1 lubricant available today


http://www.lubery.com/store/catalog/KYJelley.gif

pennzoil 15-40 on the boat

On the outdrive original quicksilver outdrive oil

mobil1 5-30 on the lt-1 engine in my Jeep.

Pennzoil 20-50