Alright guys, I have a 2004 F150, FX4, V8 Triton 5.4 liter engine. I need to know what you all recommend for changing the front and rear differential fluid. And how much to use for each. Please help asap, I want to change it asap.

 

Red Line 75W-140 (GL-5+) in the rear diff and Red Line 75W-140 or 75W-90 (GL-5+) in the front diff. 3 qts rear, 2 qts front, no friction modifier needed with this fluid.

You can get the fluid directly from redlineoil.com or from ogracing.com, dougherbert.com, Summit, and plenty of other places.

The next best bet (IMO) would be Amsoil Severe Gear in the same weight. You can get both Red Line and Amsoil SG for $10-$12/qt on the 'net, which is way cheaper than you can get Motorcraft 75W-140 Synthetic from the dealer, plus these fluids don't need that $7 bottle of friction modifier, all on top of being superior/higher end gear oils.

I recommend Motorcraft TA-31 for RTV, seals like a mother, is designed to handle high temps and drys in 1 hour.

 

Thanks, I really appreciate the help! One more question though, on the front diff. you said 75W-140 or 75W-90, is one or the other better or worse?

 

amsoil scored the highest in a lab testing page I saw.
I used lucas (#6 of 9 tested)
no problems yet.

 

Is there a fill plug on the front diff? I can't seem to find it if there is one.

 

I would follow the owner's manual recommendation regarding front diff. viscosity as they changed from 75W/80W-90 to 75W-140 at some point, IIRC.

If in doubt just look at your usage: if you're a casual off roader, using 4x4 to ride trails, occasional pulling, (i.e. limited stress on the diff) I would use 75W-90, if you're a hard core off roader hitting mud bogs, etc. (really working the heck out of the front diff and getting it HOT) I would use 75W-140.

 

Naturally, of course Amsoil paid for the testing and had total control over the samples submitted to the lab. It was an Amsoil white paper after all.

How do Amsoil's test results line up with results obtained by an independent third party?



vs.

Petroleum Quality Intitute of America

Wierd, huh?

I do think Amsoil makes a very good product for the most part, but I take their white papers and bench tests with a grain of salt as should everyone.

 

Yep, on the side of the front diff. housing facing the passenger side of the truck.

 

Man for anyone that is doing the front differential fluid, I would highly recommend picking up a set of ratcheting wrenches. The top bolt is nearly impossible to get to without them. The bolts for the cover are 1/2" for future reference.

 

I used a deep socket and rachet for the front diff I just did on a '06 4x4. You just have to push that plastic trim/plate up out of the way to get access to the top bolts.

 

How do you change front diff and tcase?

 

The front diff is just like the rear diff. Pull the diff cover, let the fluid drop into a pan, scrape the cover and mating surface on the diff, then re-seal it and bolt the cover back on. The fill plug is on the side of the diff pumpkin, just fill until the fluid level is at the bottom of the fill plug (2 qts).

The transfer case has 2 plugs on the back, a drain hole and a fill hole. Just drain then refill until the fluid level is at the bottom of the fill hole (2 qts). The transfer case is downright easy.

I use a hand pump to refill the transfer case and the front diff, as getting a funnel in there is pretty tough.

 

What did you end up doing?

 

I haven't changed either differential(s) yet. I changed the tranny fluid/filter, and the motor oil/filter. I'm going to change the differential(s) in a couple weeks. I do appreciate your help! I will be ordering the fluid from Redline when I change them, I have already checked out their website.

 

what kind of pump are you guys using to fill up the front differential? Any cheap suggestions? I can't seem to get the bottle in there to pour it all.