Differential service

tderonne wrote:
From the 2008 F53 owner's guide:

Your vehicle’s rear axle is filled with a synthetic rear axle lubricant and is considered lubricated for life. These lubricants do not need to be checked or changed unless a leak is suspected, service is required or the axle assembly has been submerged in water. The axle lubricant should be changed any time the rear axle has been submerged in water.

+1 to go by the book. Or at least wait 100,000 miles.

If you are aware of the particle counts that occur in oils without any filtration, you will change it at least once to get the break-in particles out. The manufacturers don't care about your long-term life in gearboxes.... I change mine at 10,000 from new and then every 50,000 going forward. The only filtration in most diffs is a simple magnet to try and catch the big chunks.... :) If it doesn't have a drain plug, just remove the bottom third member attaching bolt to drain it, after you drive it to get it warmed up good. :)

New to the Ford chassis, does the diff have a drain plug?

ScottG wrote:
I would replace the fluid, it's cheap insurance.

X2. You're not going to hurt anything by changing the fluid.
If it's changed, you know it's good.

Go with what your service manual says!

I change all of the rear end, differential and manual transmission fluids at about 50,000 miles to synthetics and don't really worry about them again if I don't see any leaks or weeping. It's cheap insurance and I like to see what comes out of them. Also the front hubs if they're oil bath.

Bill

I would replace the fluid, it's cheap insurance.
I have a 50 y/o car that claims to have lifetime diff fluid. I finally changed it but it was too late - it ended up needing a rebuild.
At what point do you call BS on LT oils?

From the 2008 F53 owner's guide:

Your vehicle’s rear axle is filled with a synthetic rear axle lubricant and is considered lubricated for life. These lubricants do not need to be checked or changed unless a leak is suspected, service is required or the axle assembly has been submerged in water. The axle lubricant should be changed any time the rear axle has been submerged in water.

Good idea. Change fluid. Go with synthetic gear lube of the correct viscosity and forget it for another 6 years.