Amsoil in rear diff, now seals leaking?!

[Tommyboy]

Not too long ago, well maybe 15k miles ago, I changed the rear diff fluid in my '97 Expedition. I used Amsoil 80W-90 and added they're friction modifier. Ford recommends 75w-125 in the diff, I believe. Today I noticed oil on the inside of both rear wheels, which I'm only guessing is from leaking axle seals. Could this be from the different weight fluid? What should I do, change the seals, change the fluid to recommended weight? Both? Any thoughts?

Thanks...

 

[Pablo]

If Ford called for 75W-140, then this what you should have used, synthetic or not.

I take it you checked the basics, like it's not overfilled and the breather tube is not blocked?

It is very possible that your seals were very, very slowly oozing before you changed, almost unnoticeable but then switching to the thinner synthetic it began to leak faster.

You are right down the road from me, who did you get the gear oil from? What is the dealer saying?

 

[Tommyboy]

Oh, I got the oil myself. I'm a 'preferred customer'! I'm thinking that at the time I couldn't find that weight so I got the 80/90. I read on another board where this shouldn't be a problem. Maybe some Auto-RX and a fluid change would help.

 

[MolaKule]

Ford's have strong differentials but they prefer the heavier fluids for increased shear resistance.

The Schaeffer's #267 80W90 is almost a 140 weight, so you might try this Blend gear oil.

According to my BIL (also a Pref. Cust.), try the new Amsoil SVO 75W140 next time; should be available in October.

Also check your rear brake cylinders and make sure they are not leaking.

[ September 05, 2004, 12:12 PM: Message edited by: MolaKule ]