Friction modifier

[JaysFan9292]

Hi. I'm changing my rear differential fluid and wondering has anyone had issues with the oil that has the modifier included? Can I add some extra, will it hurt adding more? Looking for some advice. Thanks.

 

[Elevated 2013]

From an old school GM mechanic’s point of view as well as teachings, it never hurt to add a touch more. I don’t think adding a little more than necessary every hurt but I would go adding extra bottles of it.


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[tidefan1967]

What brand of fluid are you using? Both Redline and Amsoil's gear lube's have plenty of friction modifier in them already so you probably won't need to add any to those. Not sure about any other brands although a few like the Mopar brand don't come with any at all so a little extra wouldn't hurt.

 

[Livinalittle]

I went with Royal Purple on both and haven’t had any issues.

 

[MRFREEZE57]

changed mine with redline, they say already has the friction modifier, seems to work ok without adding any more.

 

[John Jensen]

I asked Redline the opposite question. Is it ok to put Redline that has the modifier in a standard, no anti-slip, differential? They said no problem. That tells me some extra in an anti-slip would be okay.

 

[Pull Ya]

I think the Mopar friction modifier is pretty cheap at the dealership. Sound like a good investment to me.
Jay

 

[DILLIGAF]

Ive been running Redline for 8 years and havent had a problem yet. heck the oil still looks new after all this time.

 

[JaysFan9292]

I went with Royal Purple on both and haven’t had any issues.

I was going to go with Royal purple also. Do you remember how much you used? Looks like it's just over 2 liters. I'm pretty sure I will take the cover off.

 

[Sherman Bird]

Hi. I'm changing my rear differential fluid and wondering has anyone had issues with the oil that has the modifier included? Can I add some extra, will it hurt adding more? Looking for some advice. Thanks.

I replaced a differential driveshaft flange seal on a limited slip differential on a 2006 Expedition a couple of years ago with fluid which had additive in it. After they took the truck with trailer to the Frio River for some tubing/camping this year, they returned with a mighty groan/shudder from the differential upon sharp turns like in a Cul-De-Sac. He took it to the tire store (Discount Tire) and they rotated/ balanced the tires to no avail. He brought it to me, and I added BG friction modifier and drove 3 miles with many slow speed wheel locked turns.... problem gone!

 

[Livinalittle]

I was going to go with Royal purple also. Do you remember how much you used? Looks like it's just over 2 liters. I'm pretty sure I will take the cover off.

Had to grab my service notebook, here’s all the details I kept.

Rear diff done at 30,000 km’s, cover off, RP 75W90 (I remember buying 3 quarts

Front diff done at 120,000 km’s, drain and fill, RP 75W140 (Again I didn’t write down how much I used but I think I remember buying 3 quarts)

 

[MRFREEZE57]

I replaced a differential driveshaft flange seal on a limited slip differential on a 2006 Expedition a couple of years ago with fluid which had additive in it. After they took the truck with trailer to the Frio River for some tubing/camping this year, they returned with a mighty groan/shudder from the differential upon sharp turns like in a Cul-De-Sac. He took it to the tire store (Discount Tire) and they rotated/ balanced the tires to no avail. He brought it to me, and I added BG friction modifier and drove 3 miles with many slow speed wheel locked turns.... problem gone!

with just the redline have done a number of sharp u turns, did not notice any chatter.

 

[John Jensen]

with just the redline have done a number of sharp u turns, did not notice any chatter.

Thanks - that's good to know

 

[Sherman Bird]

with just the redline have done a number of sharp u turns, did not notice any chatter.

Neither did this one chatter for 2 years after the repair. Then, after they towed a trailer from Houston to near New Braunfels and back, they experienced the chatter. I added the BG product and the noise has gone away.