Friction modifier

[1966satellite]

I'm in the process of changing the discs in my clutch type sure grip rear end. I purchased gear oil that contains friction modifier. Do I still need to apply friction modifier to the discs before assembly?

 

[6PKRTSE]

I always add the little 4 Oz (I think it is) bottle also in each one of mine unless it's a spool obviously.

 

[Cranky]

When I rebuilt my Dana 70 rear end oil with the modifier in the oil was used and well, had to add some more since it chattered.

 

[33 IMP]

Can't hurt!. I would still add a bottle Motorcraft modifier anyway.
P.s. your not using synthetic gear oil, are you? I sure as hell wouldnt!

 

[hemi446]

I soak the clutches in a bottle of the Motorcraft friction modifier for several hours before assembling the posi unit. Then put whats left in the rear when it finished. Never have a problem. I agree with 33 IMP Never Use Synthetic Gear Lube in any rear that doesn't require it

 

[Lefty71]

Doesnt that stuff stink like nothing else on this earth??

 

[dadsbee]

Doesnt that stuff stink like nothing else on this earth??

You can smell it coming in the mail three depots away....

...best way to put it in !

 

[kiwigtx]

My lube of choice for the diff.

 

[Slap Stick]

Here it comes.....

 

[1966satellite]

I bought some Trans X limited slip oil additive and the small print says not to use it if the gear oil has friction modifier in it. My gear oil does so I'm not sure if I should use it.

 

[Cranky]

I drained the the oil that came with the friction modifier then went back with 'normal' gear oil and used 2 bottles of the Mopar stuff. It doesn't stink like the Motorcraft stuff. Also the Dana 70 takes more oil capacity.....and don't think the extra half bottle hurts. It locked up fine on a test and no more chatter plus the slight whine between 55-65 is much quieter now.

 

[F4R/T]

So silly question is there something better about the motor craft stuff vs the Mopar? I use what they call for and have no complaints... But I see a trend and wonder why?

 

[khryslerkid]

You can smell it coming in the mail three depots away....

...best way to put it in !
View attachment 1251184

Won't the bottle get chewed up?

I'll empty half a quart bottle of gear lube into the diff. Then empty the 8oz bottle of friction modifier into that bottle and shake it up. Then add that into the diff along with the second quart.

 

[khryslerkid]

So silly question is there something better about the motor craft stuff vs the Mopar? I use what they call for and have no complaints... But I see a trend and wonder why?

Cass from Dr. Diff told me once that they did a comparison test between all the different brands of friction modifiers and Motorcraft came out on top for longevity. Others can break down sooner.

 

[kiwigtx]

I bought some Trans X limited slip oil additive and the small print says not to use it if the gear oil has friction modifier in it. My gear oil does so I'm not sure if I should use it.

My diff guy has been building heads for nearly 40 years, and if he says I need the friction modifier....I use it. He is very highly respected nationwide here.

The gears in my diff are quite aggressive for an 8-3/4.

 

[Cranky]

My diff guy has been building heads for nearly 40 years, and if he says I need the friction modifier....I use it. He is very highly respected nationwide here.

The gears in my diff are quite aggressive for an 8-3/4.

Yo gears gots sharp teeth?

 

[Cranky]

Cass from Dr. Diff told me once that they did a comparison test between all the different brands of friction modifiers and Motorcraft came out on top for longevity. Others can break down sooner.

Hard to believe that Ford/Motorcraft would come out on top of anything lol

 

[kiwigtx]

Yo gears gots sharp teeth?

Hungry gears.

Maybe I should have tossed a Snickers in there also.

 

[khryslerkid]

My diff guy has been building heads for nearly 40 years, and if he says I need the friction modifier....I use it. He is very highly respected nationwide here.

The gears in my diff are quite aggressive for an 8-3/4.

Why would you need friction modifier when building heads?

 

[kiwigtx]

Why would you need friction modifier when building heads?

Diff heads.