Maya.215 wrote:
I said the same thing on changing both sides makes no sence to do one,I'm on a search for so the oil that goes in the rear differential type and weight?
I almost missed this.
Synthetic 75W90 gear lube. (Might be called gear oil.)
The parts store where I have a commercial account has been bought out by a major chain and they're getting stupid with my account so I wasn't able to find the amount required. You want to fill the differential until fluid flows out the hole. IIRC, the differential fluid also lubes the wheel bearings so you'll want to make sure it stays topped off. (I've dealt with a lot of full-floating truck axles, which includes your Dana 70, so I have to look things up to make sure I'm remembering correctly.)
Some people recommend 85W140, especially if you're carrying a heavy load, pulling a large trailer, going across southwest deserts in the summer daytime, or going up and down a lot of large hills or mountain passes. However, in spite of Alaska's well-known rugged terrain, I've never had any problems using 75W90.
If you're worried about it, stop every hour or so to admire the scenery and let the gear lube cool off.
If, during routine maintenance, the gear lube smells burnt, change it and
maybe consider going to 85W140. (But remember the thicker gear lube will be harder on the differential in the winter.) Otherwise, don't worry about.
What you folks on the east coast call mountains, we call hills. Even the Rockies in the lower 48 aren't that impressive compared to up here. If you want some idea as to what I'm talking about, google images of Turnagain Pass and Thompson Pass. There's not a lot of pictures of the roads up to those passes ... most people don't like to stop until they either reach the top or bottom. (And, for some people, especially truckers, reaching the bottom is sometimes a matter of circumstances rather than intent.)
By the way, 75W90 (10W30, etc.) means multi-viscosity. The first number indicates cold/winter viscosity, the W stand for winter, the other number indicates hot/summer viscosity. (The lower the number, the thinner the lube/oil and vice versa.)
In the old days, only single viscosity lubricants were available, meaning you had to change the gear lube in your differentials and manual transmission twice a year in some climates.
The same applied to engine oil, although I learned years ago that changing the oil and filter every 3 months or 3,000 miles, whichever comes first, extends engine life drastically. (That's why my van is still running strong after over a half million miles ... the body's falling apart by the engine's still chugging along.)
(Drats, I'm dating myself again.)
Here in interior Alaska, with the roughly 150 degree (F) difference between summer highs and winter lows, some people -- especially oldtimers -- still change their gear lube twice a year.
On the other hand, the 69/70 Explorer motorhome was the only vehicle that I could get started at -50 degrees (F) so I could go pick my wife who was stranded at work. Once the engine warmed up, the beast had no problems with the rear axle or any other components. (It took a few miles for the "square" tires to warm up but that's life up here.)
Bottom line: Keeping a Dana 70 full of 75W90 gear lube will make it last past your lifetime.
