I figure after 11 years I should change the oil in the axle and the manual trans. I was somewhat surprised at the cost of the Motorcraft 75W-140 synthetic gear oil at $25/qt., but I'm going to use it anyway. For the trans, which takes ATF, I'll use Valvoline Max Life DexMerc. So basically we're talking $125 just for the oils. I imagine if you had this done at the dealer or other shop you could easily spend $400. I can do it in the driveway. Might have to remove the spare tire but I need to do that anyway to clean the tire/wheel and lube the mechanism.
My only question is, what do you prefer; using the 'gasket in a tube' alone or using it with a new gasket? I know Permatex has the product that is designed to resist diff oil.

 

I use a thin bead of silicone sealer (RTV) and reinstall with no gasket.. My RTV preference is the orange stuff that says wont harm sensors ( or something like that)..... I use a good quality synthetic gear lube from Auto Zone.. Seems like it was $10- 12. per quart ? FORD does not make oil.... somebody puts it in the RED bottles for them. ...As long as the TRANS oil says MERCON V on the bottle, your good to go.

 

Yes, I'm aware of all that but I have a thing about using manufacturer-branded parts/lubricants. I used to go with the more generic substitutes but over the years I changed my mind. As far as Valvoline Max Life DexMerc, I'm sold on that, having been using it for years in transmissions, power steering, etc. I don't believe there's a better ATF for any use.
Thanks for the tip on the diff housing seal. I've done it both ways in the past and never had any leaks with just the sealant. I was just curious if anybody was doing it differently these days.

 

MaxLife™ Multi-Vehicle ATF is a full synthetic formulation with advanced additives to prevent the major causes of transmission breakdown and help extend transmission life. Developed to help prevent leaks, maximize transmission performance, reduce transmission wear, and maintain smooth shifting longer than conventional fluids. It is suitable for use in a broad range of ATF applications including most Ford, GM, Toyota & Honda models as well as Dex/Merc, Mercon LV and many more applications.

FORD originally filled with MERCON, but upgraded to MERCON V a few years later. That is now the recommended fluid... MaxLife meets the OLD MERCON spec, but NOT the new MERCON V spec... It will work, but there are better options.

 

For a manual trans or power steering its great. If I had an auto trans that Max Life does not cover, I wouldn't use it for that application. Each bottle has the list of approved applications.