Date sent: Tue, 15 Feb 2000 14:27:18 -0600 (CST) From: Jon Pace Subject: [80] Is oil, oil? To: 80_series@sgiblab.sgi.com Send reply to: 80_series@sgiblab.sgi.com All right, while the truck was at the dealer last week for the free timing chain replacement (which it didn't need, now I know why it was free) I had them listen to my driveline whine. They told me it sounded like the transfer case had too light an oil in it (I had already told them I had changed both diffs and the x'fer, so they assume customer stupidity). Just in case they were right, I changed the oil. Now I want to ask the all knowing ones if they may have been partially right. Soon after I got the truck, I changed the x'fer oil and put in 75W-90 Mobil 1. I checked the manual yesterday, and it called for 75W-90 multipurpose gear oil. I looked at the bottle, and Mobil 1 says its good for hypoid gears, but doesn't say multipurpose. My question: is there a difference? I'm supposed to use 90 weight hypoid gear oil in the diffs, and 75W-90 multipurpose gear oil in the x'fer. Is the only difference there the oil weight, or is hypoid oil different than multipurpose oil? I also added Mobil 1 full synthetic to the engine for the first time. Since it's probably going to remove 90,000 miles of junk, should I still change it after the first 5000 miles before I go to extended intervals, or can I go straight to 10000 right away? Thanks, Jon From: "Norm Needham" To: <80_series@sgiblab.sgi.com> Subject: Re: [80] Is oil, oil? Date sent: Wed, 16 Feb 2000 16:00:25 +1100 Send reply to: 80_series@sgiblab.sgi.com From: Jon Pace > > I'm supposed to use 90 weight hypoid gear oil in the diffs, and >75W-90 multipurpose gear oil in the x'fer. Is the only difference >there the oil weight, or is hypoid oil different than multipurpose >oil? > Jon, Hypoid oil has additives to stop it shearing with the sliding action of hypoid gears (as found in diffs). The transfer does not use hypoid gears. Hypoid oil can be used in both diff or gearbox, but multi purpose gear oil that is NOT specified as hypoid will quickly destroy diff gears. Cheers * Norm Needham * * Traction 4 / ARB Northside * Sydney, Australia * Trac4@bigpond.com Trac4@telstra.com