Who'd a thought, 4oz. of that smelly stuff and got rid of that annoying chatter coming from the rear end. Must have used the wrong synthentic lube. Thank you search file.

 

Kind of odd how well that little bottle works, isn't it?

 

What synthetic oil did you use ?

I used ROYAL PURPLE synthetic 75w - 140w and was told I didn't need modifier. well, I did need to use modifier because I also had the chatter after the oil change.

I added the modifier and after a couple hundred miles, the chatter went away.

 

I was wondering the same thing, what gear oil?? I used the RP 75-140 syn and I added a bottle of MC friction modifier later on too because I was paranoid of not using it..

 

I needed it using Royal Purple and Red Line. To get it to mix in good and work its way into the clutches, you can do figure eights for a few mins and it'll be all good!

 

I used Royal Purple and chatter was better after I changed it but the chatter has gotten worse since. Can you add too much friction modifier???

 

You'll need somewhere between 4 and 8 oz typically. You'll just slip the clutches more if you add too much. You'll get zero chatter. Sounds like you have something else going on.

 

I used RP as well but I didn't add the friction modifier and I haven't had any issues at all. So, not sure why you guys are having trouble.

 

what does this chatter sound like, i have a growling noise coming from the front end online when the hubs are locked in and the truck is in 4wd. i did the front end over and since then i have hasd this problem, dont know what it sounded like before as i had to do the front end right when i bought the truck. i figured the growling was coming from the blue seals that you have to press on to the axles. i did add friction modifier though, i think 4 ounces.

 

I don't believe friction modifier is needed in the front
Sounds like the wheel hub assembly to me.

 

You are right about the front not needing the friction modifier. Only the LS need the stuff. The front is an open diff.

 

I wonder if the schaeffers needs the friction modifier?

 

You Royal Purple user might want to read this.

 

Thank Chase, that may explain why I can't find it anymore at AutoZone or Murray's Auto.

 

Well, this was my first time using RP and so far I haven't had any issues with their gear oil. Can't say how there engine oil is because I don't use their Oil. Here is an article I found that was interesting but conflicts with the above article. Royal Purple Diesel World More MPG for Your Super Duty To each his own I say.

Besides I scored my RP gear oil off e-bay for $20 so I'm not going to cry over $20.

And that is right, you don't need a friction modifier in the front.