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My understanding is that 3J = 3.55 Electronic Locking.
I'm looking at changing the rear and front axle fluid per the owners manual but wasn't sure if I had limited slip.
Manual says 5.8 pints of Motorcraft 80W-90 premium rear axle lubricant for the front axle and 6.9 pints of Motorcraft 75W-140 synthetic rear axle lubricant for the rear axle.
When I changed mine, I bought a gallon of Lucas synthetic 75w140 on Amazon. No limited slip additive added but I did add LubeGard diff additive (not for limited slip though, supposed to prolong oil life and reduce friction). I have the 3.55 E locker as well.
Last edited by Overkill2; Dec 28, 2019 at 07:03 AM.
Reason: Add to post
Somebody correct me if I'm wrong but I don't believe any of the 11-16 single rear wheel trucks came with a limited slip rear end (at least in a lariat and up trim level). The limited slip was only available in the dually trucks. If this is the case (not completely sure if the XL could of had limited slip or not) then no friction modifier is necessary on the single rear wheel trucks.
Anyone know why the front axle requires a lighter weight than the rear? And would using the same 75w140 in the front be a bad idea? I will be dropping the oil in my rear axle soon and was going to order another gallon of the Lucas 75w-140 for the front and do them at the same time.
dirt, I have no idea about limited slips in the newer trucks.
As for using 75w140 in an axle where they call for 80w90, I wouldn't. I don't have any technical reason why not but I would use what Dana recommends in the D60 which is 80w90. I have bottles of Mobil 1 75w90 that I have and will probably use it when I decide to do the front.
dirt, I have no idea about limited slips in the newer trucks.
As for using 75w140 in an axle where they call for 80w90, I wouldn't. I don't have any technical reason why not but I would use what Dana recommends in the D60 which is 80w90. I have bottles of Mobil 1 75w90 that I have and will probably use it when I decide to do the front.
Yeah probably not a good idea to use a thicker oil and run the risk of under lubricating the diff. Bad things would happen.
As for the 3J axle code I have the e-locker and my axle code is 3J as well.
That is an electronic locker. Pull the switch toward you and it locks.
I probably will never use 4wd and I would assume never use the electronic locker.
Is it a good idea to use the 4wd periodically just to make sure it works? I have a 1/4 mile gravel driveway and could start using 4wd as I enter the driveway.
I probably will never use 4wd and I would assume never use the electronic locker.
Is it a good idea to use the 4wd periodically just to make sure it works? I have a 1/4 mile gravel driveway and could start using 4wd as I enter the driveway.
I like to "exercise" the systems on my truck so that when (if) I need them I know how to engage them, and I know how they work. On the electronic locker, be aware that it completely locks the rear end, so if you are trying to turn while using it the truck will "lunge" and tires will break loose. I've only ever used mine to back my big fifth wheel up a loose gravel drive, and if I leave it engaged and start to drive it will let you know it is still locked!
Somebody correct me if I'm wrong but I don't believe any of the 11-16 single rear wheel trucks came with a limited slip rear end (at least in a lariat and up trim level). The limited slip was only available in the dually trucks. If this is the case (not completely sure if the XL could of had limited slip or not) then no friction modifier is necessary on the single rear wheel trucks.
Anyone know why the front axle requires a lighter weight than the rear? And would using the same 75w140 in the front be a bad idea? I will be dropping the oil in my rear axle soon and was going to order another gallon of the Lucas 75w-140 for the front and do them at the same time.
I do believe that the front oil isn’t lighter, it’s heavier/thicker. Also I have driven and seen friends and families trucks/super duty’s, and I haven’t seen or encountered one of them that wasn’t a limited slip. And most where single rear wheel.
Somebody correct me if I'm wrong but I don't believe any of the 11-16 single rear wheel trucks came with a limited slip rear end (at least in a lariat and up trim level). The limited slip was only available in the dually trucks. If this is the case (not completely sure if the XL could of had limited slip or not) then no friction modifier is necessary on the single rear wheel trucks.
Anyone know why the front axle requires a lighter weight than the rear? And would using the same 75w140 in the front be a bad idea? I will be dropping the oil in my rear axle soon and was going to order another gallon of the Lucas 75w-140 for the front and do them at the same time.
You are correct. The Limited Slip was only used in DRW and Electronic Lockers in the SRW.
