Wondertwin1

What gear oil do i need for my 8.8 rear end and what friction modifier.

Synthetic??? Natural??? Amsoil???
What brand is best??
What wieght?

Wondertwin1

Oh yeah. And transmission fluid. What type and how much?? And do i need any gasket maker or anything?

bluecar5556

Trans:
MerconV, 16.2qt E40D w/4x4

Diff:
Ford 8.8" Fill 1/4' to 9/16' below fill hole (5.5 pt=88oz.)
F150/4.10:1 axle ratio, rear=synthetic 75W-140
Others-80W-90 GL-5 front and rear

I believe that's right, kinda confusing. 0_o

Wondertwin1

What brand gear oil?? And this is the best stuff?

bluecar5556

Valvoline and castrol are some of my personal favorites.

qdeezie

I use Valvoline Maxlife ATF in my trans and Amsoil Severe Gear 75w-90 in my diff, but since you do offroading (per your autosig) you need the 75w-140.

Wondertwin1

What about friction modifier?

I dont offroad alot actually. Maybe one or two big trips every other month

qdeezie

I didn't use Friction Modifier in mine and it works great.......however per Amsoil's site:

AMSOIL Severe Gear is compatible with most limited-slip differentials. If limited-slip differential chatter occurs, add AMSOIL Slip-Lock™ friction modifier additive.

Most synthetic gear oils I've seen don't require it per the label, but they do sell the FM in the rare instance chatter occurs.

Wondertwin1

I think ill add a bit just to be on the safe side. How much fluid should i need you think?

qdeezie

For the rear differential 5.5 pints which translates to roughly 2.75 quarts. You'll need 3 quarts to fill it. As far as the front differential........I'm not a 4wd guy, so I don't know to be honest. In checking my repair manuals and Amsoil's site there's quite a few different front axles available regarding capacity.

Per Amsoil.......
Differential, Dana 44 Front..........3.6 pints
Differential, Dana 50 Front..........3.9 pints
Differential, Dana 60 Front..........6 pints
Differential, Dana 60-IU Rear..........6.4 pints [2]
Differential, Dana 70-2U Rear..........6.6 pints
Differential, Dana 70 HD Rear..........7.4 pints
Differential, Dana 80 Rear..........8.3 pints
Differential, Ford 8.8 or 9 R Rear..........5.5 pints
Differential, With 10.25 RingGear Rear..........7.4 pints
Transfer Case, BW4407..........4.1 pints
Transfer Case, BW1356E W/ PTO..........12.3 pints
Transfer Case, BW1345..........6.4 pints
Transfer Case, BW1356E/BW1356..........4.1 pints

However, if it was me, I'd get 3 quarts for the front to start with if you have no way of recognizing which front axle you have.