I need to replace my fluid in my 99SD V10 4R100 what kind of fluid should I use ?? I pull a #7000 boat on the weekends, just about every weekend around 15 miles to the water and on flat ground

 

You need to use a MERCON fluid. Do not use a MERCON V fluid, or a fluid that has both MERCON and MERCON V ratings.

 

You may benefit from using a Synthetic Fluid for your truck since you tow a boat can't go wrong with Redline and I think it is there D4 ATF but am not sure check out there website and then give them a call they will be more than happy to help you. www.redlineoil.com

Richard D.

https://www.f150online.com/galleries....cfm?gnum=2479

 

What Mark said, MERCON, and not dual use fluids. The Motorcraft MERCON/DEXTRON III is fine, if you want ot go synthetic, use Mobil 1.
My own personal opinion on the Redline, Trick Shift, Royal Purple, AMSOIL etc... is they're about as good as WalMart brand in a very nice bottle. The Mobil 1 seems to be better if you're someplace hot, but otherwise just plain ole Motorcraft will be okay. I personally would never pay for designer fluid, I've never seen any of them that makes any difference on how th tranny feels or works.
In the end, it's basically hydraulic fluid with some Red dye #3 in it. The different grades not mixing or being interchangeable is mostly a problem with compatibility with the friction material and seal compounds.


G