Rear Axle Oil Change Interval

[Archive]

Last Fall, 14,000 miles ago, I changed my rear fluid using Amsoil series 2000, 75-140 weight (Dana 70 with Mag-Hytec). I tow a fifth wheel about 7000 miles a year. My owners manual says to change rear axle fluid annually if you tow. The oil is clean and I get the normal amount of fuzz on the dipstick magnet and all looks good. My question: Do I really have to change fluid annually with only 14k on the oil? Using Amsoil? The local Amsoil dealer thinks I am wasting money to change it this soon. I would like some answers from those of you most familiar with the Dana axles. Thanks for your help and opinions...

------------------
Ron

'96 Club Cab 2500 4x4, 4:10LS, Camper/Tow package, Auto, BD Pressure Loc, Mystery Switch, TST 230/605, Cat under "Test", Cummins Chrome, Mag-Hytec rear and trans covers, Boost, Pyro and trans gauges, Optima Red Tops, All black. Tow 14k HitchHiker triple glide 5th Wheel. Also use 9. 5' Lance camper. NRA Life Member.

 

[Archive]

You're Amsoil dealer may be right. The milage on the oil isn't enough to warrant change. The other function of the oil is to absorb moisture (condensation) in the diff case caused by temperature changes. It may be nearing its capacity to do that based on time.
To be sure, do an oil analysis. Your dealer has the kits for under $20 (postage paid!). Do this a couple years in a row and you'll get a good trend as to diff lube life. Then you can share it with your pals here at TDR!

------------------
'94 3500 4x4, 204,000 miles, Never had a cat, Auto w/shift kit (thanks Dave G), 3. 54 Gears, TST #5 plate, 235-85-16s, Rancho 9000s w/remote, Isspro gauges inplace of cupholder & Amsoil Bumper to Bumper. NRA member. Blue Ribbon Coalition member.
"Warrantee? We don't need no stinking warrantee!"