differential fluid

[crownvicjim]

doing some work on my rear end and gonna have to replace the gear lube. whats the best stuff to use? and do i need a friction modifier?

 

[Icarus]

No modifer needed as the stock diffs are all open.
I'm running Ford Synthetic 75W140 in mine.

 

[k9t8m]

Me too.

 

[crownvicjim]

thanks guys

 

[98LSC32V]

Amsoil Severe Gear 75w-90 or 75w-110 for stock rear end applications and 75w-140 for lower gear ratios with trac-loc.