Royal Purple Q

[Woppy V]

I am at 75,000 miles and am going to change out my diff oil. I have a 4:11 non limited slip. All i need is about 2.75 quarts of 75w-140 royal purple and some kind of silicone sealant for the cover when I am done right? Nothing else ~~ no other dire procedure? TY

 

[Jeff C]

I thought you used 80-90 for non LS? Todd?



I used a gasket and silicon on the diff, no leaks. I'm planning on getting a diff cover in the next few months and will go with a lube locker gasket then; no rtv on that.

 

[bRAD Baltzer]

75w-140 in the rear differential (synthetic) and 80w-90 in the in the front axle. WoppyV, think its pint not quarts?

 

[Larry Phillips]

I have a 3:73 non limited slip in the rear, and it uses 80-90.

 

[Woppy V]

good stuff! gonna go to the shop tommorrow. any suggestions on the silicone?

 

[Todd Z]

Directly from the owners manual...



Front:

80W90 - 2 Qts



Rear:

80W-90 NON LSD - 3Qts



Silicone, Black OR the ULTRA GREY, I prefer Gaskets....



75W-140 LSD WITH ADDITIVE - 3Qts and additive bottle.



Transfer Case:

ATF DEX - 2 Qts



Todd Z

 

[Woppy V]

Thanks! Pep Boys told me they only carry RP 75W-90 and 75W-140 will the 75w do the job or does the weight have to be dead on?

 

[Jacob Dryer]

The first time I did my rear diff fluid with only RTV (which is what ford uses) it leaked.. I don't know if I did it wrong or what but either way it leaked so it needed to be fixed.



The second time I got a Mustang gasket and it's still rolling strong with no leaks.

 

[EddieS'04]

I used to seal my Mustang with the ultra gray silicone. Go around the bolt holes also. I wipe the area with alcohol first, no leaks.

 

[Woppy V]

thanks for the advice... just the last bit.



is rp 75w-90 the stuff to get? they dont carry a 80w-90 royal purple at the store.

 

[EddieS'04]

I would stay with what the book calls for. There is a reason for it..

 

[Todd Z]

Woppy,

I used the 75 in the adren..... The 03 is getting that too....



Todd Z

 

[Gavin Allan]

How long do you let the silicone set up before filling it back up?

 

[Todd Z]

Gavin,

IF you clean it real well and put it on correctly, I have filled it right after tightening the cover, But I would say Waite 1 hour....



The Mustang 8.8 Gasket works, and then you can go to it.... The gasket is $2.00 on ebay..



Todd Z

 

[Eric Pennal]

Yeah, I don't think RP diff fluid comes in any other weights than 75W-90 or 75W-140. I bought the 75W-90 for mine. Close enough in my book.

 

[Dingo]

I'm a RP dealer. I can get it in 75W90, 75W140, 80W90, 85W140, and SAE 90.