dino GL-5 in place of synthetic?

[cobravenom71]

A customer of mine is complaining that his rear diff is whining after a service at our location.
We mistakenly installed dino GL_5 (limited slip additive included) instead of the Ford- recommended synthetic GL-5. Vehicle is a 2004 Ford F-250 4-wheel drive. Service was done less than 1000 miles ago, and the vehicle has less than 30K.
I am aware that there may possibly be a seal compatibilty issue, but would it cause the the unit to exhibit mechanical problems?
Thanks to all.

 

[unDummy]

Synth's tolerate the heat better.
If the vehicle isn't worked(plow/tow), then I doubt that the mineral oil caused any issues.

Get the fluid changed.

 

[MolaKule]

I would check my records and see what viscosity was put in there.

It may be his diff is loosey goosey and requires a thicker fluid if 75w90 was specified.

Most Ford rear diffs require a synthetic 75W140 GL5, MT-1.

 

[TheLoneRanger]

Ford has had lots of issues with noisy rear diffs in late model trucks. One explanation is because of poor NVH in the diff mountings, but the jury is still out. They don't seem to fail, just make noise.

They do require syn 75W140, but using a dino wouldn't cause the noise, although using the lighter weight oil would contribute (to an already noisy situation).