What's the correct FRONT differential fluid?

[Gary M]

For my 1999 Expedition 5.4 4x4. I thought it would be a simple matter to change out the front differential fluid. The owner's manual calls for 75w90 as do the limited online sources I checked. But various dealers and Ford Quick lube centers differ on what the current item is, confusing the matter. Some claim its 75w-90 but don't have it in stock, while others say its 75w-140 (same as the rear). All Motorcraft. Does someone here have current correct info on the proper Motorcraft fluid to use for the front differential in this rig? Thanks

 

[AWAR]

I used synthetic 75/90 from Napa in my 03 front diff, I have synthetic 75/140 for the rear end.

 

[Gary M]

I'd guess the NAPA item may be Valvoline which is what I may go with if I can't get a Motorcraft answer. Thanks