Discussion in '2005 - 2009 Specific Tech' started by Riggs, Dec 29, 2007.
How often should you change the rear differential fluid/oil?
According to the 2007 Owner's Guide--Ford design rear axles contain a synthetic lubricant that does not require changing unless the axle has been submerged in water.
ok question... The LSD unit on a Ford Mustang GT (factory unit) is a clutch type unit which requries maintenance by replacing clutch packs shouldn't you do a fluid swap when that happens?
Anytime you get inside a differential you should change the gear oil. I know Ford says it's not necessary to change the oil, but I say every 50-100 k miles because you do get some metal particles in the oil from gear break in and normal wear and tear which ends up flowing through the bearings. You will have a better chance of not having a noisy axle bearing if the fluid is changed once in a while. It certainly won't hurt.
Mine was changed at about 5k with the install of a new ring and pinion
I changed again recently at 35k with Royal Purple. (I should have done it again after R&P breakin but didn't)
The fluid was quite funky and had more solids than I would have liked to see.
After 3k miles on the Royal Purple differential fluid alone I have noticed allot of tire slippage under load in turns.
I am going to be adding the Ford Friction modifier.
If it sounds too good to be true it probably is.
Royal Purple Gear Oil
"All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary."
I used the exact same gear oil in My Grand cherokee, and had the same ? to myself about the modifiers - I've had no slippage tho --- everything is tickity-boo!
I changed my diff fluid about 10,000 miles after having my 4.10s installed. I used a petroleum based gear oil and not a synthetic. The place that changed diff fluid only does gears and differentials. Here is there tech tip about diff fluids.
I would be interested to know what makes them say that organic oil provides better protection. I'll be sticking with the instruction of Ford and the sticker on my differential.
I'm just glad to have this resolved before winter.
I could see this putting me in a tailspin on snow or ice.
They mention Schaeffers, which has a very robust additive package. The additive package makes a bigger difference than if the oil uses a synthetic base stock. However, generally speaking, an over the counter synthetic will suffice but I prefer to order Redline synthetic gear oil.