Chinook RV

Well I have serviced everything except the rear end oil in my 1998 ford Concourse. I only have 65000 miles on it but am leaving on a 4,000 mile trip up mountains in new england. Oil is not low. I remember checking it but was thinking about a better performance rearend oil. Any suggestions? What is everyone using? Also need to add SOMETHING to my daily driver 2006 F-150 as the rearend in it has been whining for sometime now!! 110,000 miles on it.

This is on my 'to do' list too. I haven't determined what exactly I am going to do. Here is the page out of my manual if you don't have it.
I'm considering Amsoil, was looking their website and they have a vehicle search that lists what your vehicle should use. They have a number of listings under the differential tab, you are going to have to know exactly which diff you have. This link it to my year.
https://www.amsoil.com/lookup/auto-and- ... =us-volume.
One question I still have about the Amsoil is since some are labeled for limited slip is does the additive still need to to be added.
Hope this helps some.

The Ford manual has some very confusing "specs" for our axles. Whoever wrote it is not my favorite person

I got it figured out though, and there are details in this thread:

viewtopic.php?f=3&t=1455&p=13389&hilit= ... est#p13389