I use the following:

Amsoil 20/50 in crankcase , change @ 5k intervals
Amsoil 75/90 in tranny , change @ 10k intervals
HD formula + in primary , change @ 5k intervals

I change my tranny and primary earlier than some
but I figure that WON"T hurt it, know what I mean.

 

Follow my dealer's recommendation. Change all at 5K. Can't hurt. The trans only uses 1 quart and the primary uses 1 quart.

 

HD Syn3 in the tranny and primary when I winterize, they are good for the whole next year.
HD 20w50 mineral oil goes in the motor then too with a new filter and then gets changed every 3K.
So I may do 3, 4 or 5 oil changes a year .... tranny, primary only once.

 

For my '06 EGC I use:

Mobil1 15-50 Synthetic $26.00 5qt. jug from Wal-Mart. Change every 5K miles.

Mobil1 75-90 Synthetic Tranny Oil $8.00 any auto parts store. Change once a season.

Castrol GTX 10-40 Dino $2.50qt for Primary from Wal-Mart. Change once a season. Using a synthetic in the primary is simply a waste of a good synthetic oil and a waste of money. Primary oil is not intended for lubrication. It is a coolant.

HD Super Premium Oil Filters. I buy 6 at a time from either Chicago HD or Zanottis online @ 20% off. Your filter is the weakest link in your lubrication cycle, why scrimp on it? It has the best filtering rating of any filter on the market. Change every 2500 miles.


Dayum, I luv oil threads.