I have a L6 3.73 E-locker on my 2011 F150. I know this is probably just like asking which motor oil to use and there is no best brand but I'm looking to do this for the first time. I don't need the friction modifier with the Elocker like a LS. Just tackling the rear diff for now. Sounds like the front diff is a real pain and really does not need changed very often, I've probably only used the 4x4 a max of 3K miles but hard use. I might change the transfer case fluid this time, though. Any fluid that is particularly better than the other for the rear diff and transfer case?
Valvoline 75-140 seems to be the cheapest big brand full synthetic. All the others seem to be around the same ~ 20, dealer wants $22/qt. I'm leaning towards Amsoil Severe Gear 75w-140 at the moment, unless I should just save the $6/qt and go valvoline.
My plan
Obtain replacement seal
Obtain some rtv for sealant
3qts of fluid (takes 5.5 pints) 75w-140
Unbolt read cover to drain fluid
Razor blade the surface to remove old sealant
put a small bead of rtv on the diff cover, place seal, then more rtv
bolt up the diff cover, torque to 30 and then a final torque at 36 lb-ft
Wait atleast 1 hour
add fluid until it comes out
Clean and replace drain plug
Transfer case seems pretty simple. Unscrew plugs, drain, and refill with motorcraft transfer case fluid. Should this be done at 50K or just wait until I do the front diff?
1.6qts XL-12 fluid for $12/qt. or Amsoil OE ATF.
Did I miss anything?
11 F150 Rear Diff fluid change - First time
- Thread starter volk06
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No gasket on your cover from factory, just RTV. You can get covers with drain and fill plugs so you don't have to remove it the next time.
I would just use the valvoline if its the cheapest Syn. I have not seen any major issues with the rear diffs on those trucks.
The front diff is a pain to get to and work on. The last one I did he never did any major off roading and it was still a little milky. I think the breather valve was not working properly as I did not see a large amount of water in it. So at least check the front diff to make sure the fluid is level and not bad.
Transfer case there is Syn transfer case fluid from Valvoline and some others. Unless you are beating on it I doubt you will notice a difference so buy based on price and comparability.
I second getting The Right Stuff gasket maker and skipping a paper/cork gasket, no need to use both and you are more likely to have leaks if you use both. Cleanliness is the most important factor when it comes to RTV so I would use some brake cleaner to clean the surfaces prior to application. FWIW: I poured diff fluid in within 10 minutes of setting my cover the The Right Stuff and haven't had any issues in the year since the change.
I've used the Valvoline on previous changes. As noted, its a bit less expensive, readily available, and seems to do the job well.
Ditto on the RTV seal. No paper or cork gasket is necessary. I had time, so I've let mine sit for w few hours before filling with fluid to allow the RTV time to cure.
dnewton3
Staff member
Use any lube that is approved on the SAE J2360 list and you'll be fine.
Using a syn will give you longer OCIs.
http://p-r-i.org/other-programs/automotive-qpl/lubricant/
(lower left; see the "Current QPL listing")
Any of these have passed the very stringent test; dinos and syns alike.
Your truck will not know the difference between using Amsoil and the Valvoline. The only difference will be the weight of your wallet after.
I used a J2360 compliant 80w140 full synthetic in the diff of my old Ram 1500. It cost about 9$ a liter. Mobil, Amsoil, Royal Purple et were all north of 20$ a liter up here. My diff did great on it. Lots and lots of heavy towing and the gear oil too longer to darken up during my change intervals. The gear set look pristine after 140+ thousand km of hard use.
Everyone gets worked up on this forum, always need to run the latest and greatest, when in reality we dont.
Originally Posted By: dnewton3
Use any lube that is approved on the SAE J2360 list and you'll be fine.
Using a syn will give you longer OCIs.
http://p-r-i.org/other-programs/automotive-qpl/lubricant/
(lower left; see the "Current QPL listing")
Any of these have passed the very stringent test; dinos and syns alike.
A better gasket for differentials that is not messy, not silicone or rtv, IS LUBELOCKER. It's from the Jeepin' community. It's reusable and it's far easier to deal with than cork, the rubber, silicone and whatever else out there for gasket material.
I used the Valvoline 75w-140 in my Brother in laws '04 F150 with the 9.75 with no issues, would use it again. Cheap from Advance Auto using their online discount coupon.
I have also used Lucas 75w-140 and ST Syn 75w-140 (what is in it now) in my '02 with the 9.75.
Also never used a gasket, just the stuff in a tube made for differentials.
Since you don't have a clutch LS, you don't have to worry about adding the Ford XL-3 Friction modifier, all fluid needs it if you have the Ford LS clutches (even if the fluid "includes" it). That is some stinky stuff.
I have an AWD, and have been planning to do this fluid replacement also. My vehicle also has a transfer case, and a rear diff. I've done plenty of reading and going through reviews. The 2 fluids that stood out amongst most was Royal Purple and Amsoil. RP had many good reviews, and some were mixed, Amsoil had practically ALL great reviews, so my and my final choice was Amsoil Severe Gear. I do a lot of city, stop-and-go driving, and short commutes, so I wanted the Severe Gear over they're regular gear oil. My Buick also using 75w90. Very difficult to find, as I'm in Canada, so local big box stores don't carry it on the shelf. Had to special order it through a specialty shop, and it wasn't too expensive: $20 CAD per quart. Surprisingly our GO-TO big box store up here which is Canadian Tire has started carrying Royal Purple products, and the RP 75w90 is $25/quart.
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