I just picked up a 1999 f350 wih the 7.3l in it dually

I was wondering what type of fluid goes in transfer case, power steering and front and rear diffs.

I wanted to change them out as all other fluids have been completed recently.

 

Welcome NBT,

Mercon V and 80W90 GL5 gear oil for front diff
and 85W140 synthetic for rear with two bottles of XL3
LSD additive if it is LSD and it will not hurt it if not LSD
or you are not sure. It will be hurt if LSD and additive not
installed. XL3 is stinky, be careful with it. Good fortune.

 

They don't call XL3 (Friction modifier) stinky stuff for nothing...

 

You have a Dana 80 rear end and I believe a Dana 60 front end. The front is 80-90 and the rear is either 75-140 or 80-90.

The best fluid to use is mobil1 synthetic ATF in the transfer case and power steering.

 

mercon v for the power steering also?

and thank you for fast response

 

Yes, Mercron V for transmission, Power steering and transfer case

 

cool thank you

How can I tell what rear end I have in it for sure dana 80 dana 135 or for 10.5 is there an easy way to figure it out

 

Its a Dana 80. 10.5 is SRW and D135 was in the 450+ trucka

 

Start at page 212 of your owners manual. I've attached the owners manual and the diesel supplement in PDF format for you. You should save these to your PC.