Ford Positrack Lubrication

I have a Ford Positraction Rear Differential with the clutch plates. I may have it named incorrectly. I have purchased the Ford Racing Friction Modifier (part no. CM-19546-A1) for the differential 's lube. My question is do I need to run a silicone based lube or will the regular 80/90 weight gear lube be compatible with this Ford product.
Thanks

 

Do not run silcone, just the good old 80-90. The guy who built our Trac Locks specified exactly that. He said silicone will cause chatter issues. We also use the modifier.

Don

 

That Ford posi additive is the nastiest smelling stuff I've ever used--but I guess it works.

I keep Gm additive in stock and use it in Fords and GMs. Never had a problem with it, but you probably want to use Ford products in Ford parts.

 

Quit sniffing your rear end.

Don

 

Wow,stick your finger in the hole and sniff the drip,never thought of it that way.
Thanks don I am now traumatized for life.

 

When you say silicon, do you mean synthetic? As in synthetic vs regular? I use the synthetics as they have a metal conditioner and have no affect on the clutches. they have different formulas, get the one for posi's with clutches.
Somethings are best left unsniffed, not exactly sweet as dew on roses you know.

 

Thanks for the advise. I originally sent an email to the Jack Roush Racing asking the same question figuring they would be knowledgeable about the Ford products. They replied in a day with the most evasive answer a person could phrase.

 

When I worked for Chrysler,they posted a service bulletin stating that 75-140 synthetic was used with a towing option and 75-90 dead dinosaurs for everything else.
If it had a posi(and ours were clutch type) that friction modifier was not needed with synthetic.
Every time I had changed synthetic without modifier I had a complaint of chatter on turns,so I would add two bottles of modifier to the diff and it would rectify the issue.one usually would not do it.
Chrysler has had several issues with clutch chatter in trans as well as diffs. So the clutch material may be a little different from ford but it can't be that much.
Hope this was helpful Gary

 

Not quite the case. I've got a 9600 sq. ft. shop and was changing gears in a Ford in the back corner. I'd left a 4 oz. bottle of the modifier I bought from the Ford Dealership open when I left for lunch. When I came back and opened the door, it smelled like a family of skunks had moved in. The stuff is worse than rotten gas, but I guess it works.

 

He must be a wanna be politician, they are good at saying a bunch, while actually saying nothing.

 

I just went to the Chevy dealer up the street and used their small bottle of additive.