KingDeleted

Go to ford. Give them your VIN. Purchase the correct fluid.

Dafox

I apologize to anyone I offended with my third post. My reasoning for making it was in no way intended to be an ***, or to belittle any person here. My F150 is my primary mode of transportation. I travel a fairly great distance for work. I work down some of the worst roads you could imagine. While driving one of these roads to get to the job site, I had to drive through some deep mud. Long story short I hit something solid under the mud. Nothing was seriously damaged, except my rear differential cover was damaged. Turns out all the fluid drained from the differential. Luckily this didn't happen all at once and I noticed the oil in my driveway the next day. But my primary was now sitting in my driveway, differential cover repaired and differential ready for new oil! Nobody I know had a real answer to the question I posed here. So I took the question here, to the real professionals, (F150 owners). Now, personally, I consider an answer where someone belittles me, AND, tells me to add sawdust to my F150's drivetrain, as not only VERY rude, but also very childish! Was I impatient? Yes sir. Most people would be impatient knowing their primary mode of transportation was sitting useless in the driveway! Again, I apologize for offending with the third post! Which does nothing to address the childish answer I received! Much too old to deal with snowflake idiots who get mad at a simple question. Sir I am not referring to you or anyone else, other than the clown who suggested I add sawdust to my drivetrain! (I'm sorry, Gasoline, oil, and wood shavings!!!)

PerryB

Royal Purple 75/140 syn. is excellent. Both my 05 and 13 call for 75/140 so I'd have to think yours does too. If you have a clutch-type LSD you'll need to get some friction modifier. Even if the RP says it has it, I give them a 50% supplemental dose.

Dafox

Thank You PerryB. Very much appreciated sir.

Kkline

I was actually going to give you the right answer but because you were being rude I gave you what you deserved.

Guys on here are good people and you started off after 3 posts being an impatient entitled brat. If I’m a snowflake because you got your feelings hurt then so be it.

I’ve helped answer plenty of questions and had others help me quite a bit.

Dafox

Mr. Kkline, I apologize if you were offended by my third post. It was never intended as being rude nor entitled. I am a plain simple kind of guy. I normally speak my mind without regard to "feelings." I am sorry your feelings were hurt. As I said that was never my intention. Now that I have gotten that out of the way...Props to you sir. You have answered posts from people in need. Please, feel free to "not" answer anything I may post in the future. Nothing you could say would make me believe you were giving accurate information. Not after your first answer I received. Thank you sir! Have a most wonderful life. I will regardless of those so easily offended. Good night sir!

sdmartin65

An interesting thing about a limited slip differential is without the friction modifier it will grind and make horrid noises going around a corner. It will do this to a lessor if not enough friction modifier is added. If FM is added but not needed it won't harm anything.

Pussywillow

Check Amazon. When I did mine a little while back I think I remember seeing it on Amazon. I ended up purchasing from the dealer.

Dafox

Thank you for the reply. I did end up using the Royal Purple. It had friction Modifier already in it. However I liked PerryBs reply, so took his advice and added another 50% to the differential. By 50% I mean another couple ounces. Greatly appreciate your help, thanks again sir.

Dafox

Thank you for the reply and suggestion. I would have much preferred using the fluid recommended by Ford. However my situation didn't allow for getting my hands on that fluid in a timely manner. Dealer was not an option at the time. Again, thanks for the reply.