Well it depends on whether or not you are under warranty, or if it is a gas or diesel engine. Are we talking a D6 370 IPS or an AQ130 with a 270? If you are dumping it into a 5.0, 4.3 who cares.
At the end of the season it is important to change your oil because used motor oil is acidic and you don't want that sitting in your block all winter.
I have been looking for a couple of Duoprop owners to get together and buy a 55gal barrel of lower unit gear lube. Waaaay cheaper that way. Not common but when it pops up for sale I'd sure love to snap it up and change whenever the season/hours dictate. Oil is cheap...unless you buy it by the gallon. I'd assume that you use the Synthetic 75W-90 gear oil...
Thank you for the information as usual. I'll give them a try. Yup, I've been able to find the correct gear oil at a "bargain" for only $35/gallon...provided that I purchase a 55gallon barrel. When it's $100/gallon retail I'd SWEAR there was gold in it!
I used to buy my drive oil at Inlet Petroleum in town, i bought it in 5 gal pails it was a chevron product that had the same specs as the volvo oil, i do remember it was orange amber color, used it for many years in the drive that had 11,000 hours on it. By the way i only changed the oil in the drive once a year and i averaged 800-1000 hours/year but i did have a aftermarket oil level tank installed so i could always see the level and color of the drive oil, it was called a Unit Saver. Used Delo 400 in the engine. They also had all the filters for that 41 volvo engine they used to have WIX brand filters, if anyone needs the numbers pm me. Another fish choking buddy of mine used to buy his "volvo oil" at walmart and never had any problems with his drive.
Steve are you telling us you had 11,000 hours on an "outdrive" :topjob:
Amsoil 15W-40 Heavy Duty Diesel Marine is easy to find and should work well and many of the charter guys run the Marine gear lube in their drives.