How much fluid for front and rear Dif. and additive for 2004 ,5.7 1500 ram with 3.92 gears and LSD and weights do you need for a change and inspection of gears

 

80w-90 for the front 1.75qts I think?
75w-140 for the rear 2qts plus 4oz friction modifier
Now, both front/rear use Full Synthetic fluid. Mobil 1 and Royal Purple have LSD additive in them already, but your rear diff uses 2.25qts of fluid and 75w-140 is twice as much as 80w90 for the most part. It's cheaper to buy the friction modifier and add it in anyways rather than buying 3qts of 75w-140 for a lousy .25qts.
Any rtv hgih temp sealant will work. I like Permatex 1-Minute gasket maker myself.

 

can I use any additive for posi unit or should I stay with factory Mopar additive ?

 

I didn't use anything, just Mobil 1 and stored the rest of the bottle for next time. I haven't had any clutch issue's at all. Your suppose to use Mopar stuff, but they don't even manufacturer it themselves and they don't even make the differential themselves...lol They only go off of specs, and all modifiers have to meet certain specs like oil does. Any brand will work really. I guess if it makes you sleep better, get the Mopar stuff, but I'll never buy it.

 

im fixin to do both my axles...id say spend the money and get the RP...can go wrong with it

 

Thanks

 

Can or can't go wrong with it ??????????????????

 

Differential Fluid - Volume: 1.75QTS. ( 1.7L ) - [API - SAE 75W-90 Gear Oil] - FrontC205F
Differential Fluid - Volume: 2.38QTS. ( 2.3L ) - [API - SAE 75W-90 Synthetic Gear Oil] - Front9 1/4 AA
Differential Fluid - Volume: 2.38QTS. ( 2.3L ) - [API - SAE 75W-90 Synthetic Gear Oil] - Rear,10 1/2" AA
Differential Fluid - Volume: 2.45QTS. ( 2.3L ) - [API - SAE 75W-140 Synthetic Gear Oil] - Rear,9 1/4" - [With TRAC-LOK add 4.0 oz. of Limited-Slip Additive.]
Differential Fluid - Volume: 3.83QTS. ( 3.6L ) - [API - SAE 75W-90 Synthetic Gear Oil] - Rear,11 1/2" AA

 

I have RP in all of my truck. It is not cheap but I feel it is best and am comfortable using it

 

Thanks for all the advice I used Mobil 1 for the fluid change.. everyone was out of Royal Purple , MAN those top bolts on the front Diff are a pain to get to.