[kster]

I did a search and couldn't find much. Are crush washers needed for the drain or fill plugs on either the transmission, PTU or RDU?

I'm going to order:
MOTUL DCTF (transmission)
XY-75W140-QL (PTU)
XY-80W90-QL (RDU)

Thanks.

 

[RSt~n~peace]

No crush washers. Also you need friction modifier for the RDU fluid.

 

[kster]

No crush washers. Also you need friction modifier for the RDU fluid.

Thanks! Which friction modifier do we need? The 80W90 diff fluid is not enough?

 

[MorningZ]

Supposedly in the service manual is says something along the lines of

"For a complete drain and refill, Torque Vectoring RDU requires addition of Torque Vectoring RDU Gear Oil Additive, Number XL-19"

Damned if I can find that "XL-19" anywhere though, I just spend 5 minutes searching for it online and it keeps pointing me to forum posts (like this one)

 

[kster]

From searching, looks like the XL-19 is a special order fluid. Summit Racing claims to carry it as well:

Motorcraft Friction Modifiers XL19

Find Motorcraft Friction Modifiers XL19 and get Free Shipping on Orders Over $99 at Summit Racing! Motorcraft Friction Modifiers allow your clutch-type differential to operate smoothly. They help eliminate the grab and popping—especially during turning—so you can cruise in comfort. Order the...

www.summitracing.com

 

[RSt~n~peace]

You can find it on various sites. Here is tasca. https://www.tascaparts.com/oem-parts/ford-additive-oil-friction-modi-xl19

 

[GotBoostRS]

Also, if you wanted you can just buy the Redline 75W-85 and there’s no need to add additional friction modifier. The Redline fluid meets all standards and already has an friction modifier additive. I replaced tranz,PTU,RDU, and brake fluid with better quality so o didn’t have any issues on track days.

 

[Prismatic]

I agree, I have run both redline and amsoil severe duty without the xl19 modifier.

 

[Max]

No crush washers. Also you need friction modifier for the RDU fluid.

Out of curiosity, do you need to use high temperature thread sealant on the PTU/RDU fill and drain plugs or no?

 

[misterchonger]

Out of curiosity, do you need to use high temperature thread sealant on the PTU/RDU fill and drain plugs or no?

No, just torque to spec.

 

[Max]

Thanks for replying misterchonger. Does anyone know how the PTU/RDU fill & drain plugs seal against leakage? The PTU/RDU fill and drain plugs don't have o-rings on them. Crush washer's aren't used and thread sealant isn't needed.

 

[misterchonger]

Thanks for replying misterchonger. Does anyone know how the PTU/RDU fill & drain plugs seal against leakage? The PTU/RDU fill and drain plugs don't have o-rings on them. Crush washer's aren't used and thread sealant isn't needed.

The drain plugs will seal without issue unless the threads are damaged. The workshop does not specify using any sealant before reinstalling. You can reuse the same drain plugs also.

I've not changed the fluid on the RDU but the Trans and PTU are straight forward if you've ever changed fluids before.

 

[Max]

The drain plugs will seal without issue unless the threads are damaged. The workshop does not specify using any sealant before reinstalling. You can reuse the same drain plugs also.

I've not changed the fluid on the RDU but the Trans and PTU are straight forward if you've ever changed fluids before.

Thanks misterchonger - this helps a lot. I thought the oil might leak through the threads. Maybe the metal drain plugs press up against something plastic/rubber/PTFE inside the sump ?

 

[kster]

I'm still waiting for the XL-19 to arrive from my local dealer (they said it would take a week). But the bottle from Summit Racing is here.

 

[kster]

Also, I got a bottle of 75W-85 Hypoid Gear Lubricant for the RDU (instead of the XY-80W90-QL as I mentioned in the original post). This is what the service manual calls for I believe.

 

[Sampick]

That might sound like a weird question, but I am wondering where do you refill the rdu? I see where the drain plug is, can't see where to refill it. thanks!!

 

[JamoRS]

I've attached a pic to show you....

 

[Sampick]

Thanks a lot!!

 

[RSt~n~peace]

It’s difficult to access the fill port. I stuck a hex (allen) socket in the plug and used a ratchet wrench on the shaft of the hex to remove and install the plug. There isn’t enough room to get a normal ratchet on the hex socket.

 

[Disownd]

I agree, I have run both redline and amsoil severe duty without the xl19 modifier.

So its safe to run my amsoil severe gear 75w-90 without the modifier? Ordreded some then read in the back of it about the slip modifier.