??? what does the friction modifyer actually do in the rear end. does this make the clutch packs slip in the limited slip or does it keep them from slipping too much. also, what are you looking for when you do the figure eights after changing the rear end oil when you have limited slip? i am getting ready to change my rear end oil and i cant decide between amsoil or royal purple? thanks for all the help--from this new guy!! ???

 

There are several on this board with a lot more knowledge about lubricants than I have, so I will leave the "what does it do" part of your question to someone else. But, if you do not have a limited slip rear end, friction modifier does nothing.

Driving in figure 8's mixes and distributes the gear oil through your clutch pack. With a functioning limited slip you should feel some hop on the inside wheel on a tight figure 8 style turn. If you have too much friction modifier a tight turn like that will be smooth as silk (no clutch engagement). If you have too little you will end up with excessive inside wheel hop or grab even in daily driving with gentle turns (excessive clutch engagement). What is happening here in simple turns is that your clutch pack "thinks" that the outside wheel is slipping because it is rotating much faster than the inside wheel, so it "sends" more power to the inside wheel which causes it to "hop".

When you are doing your turns, get on the accelerator. Limited slips work best when torque is being applied. You will not "feel" accruate results if you just idle around the turns.

It is best to fill your diff a little short of full and go for a drive with no friction modifier. Add as needed 2 ounces at a time until you like the feel.

Good luck.

 

thanks for the info on the rear end. i do have the limited slip, everyone seems to say you dont need modifyer if you use synthetic oil?

 

[quote author=COYOTE556 link=board=4;threadid=16220;start=0#152301 date=1056345289]<br>thanks for the info on the rear end. i do have the limited slip, everyone seems to say you dont need modifyer if you use synthetic oil?<br>[/quote]<br><br>I needed the modifier on mine after installing Mobil1 despite what the label said.

 

If you decide to go with Amsoil, I did ;D, there are 2 different gear lubes, depending on if you have LS or not.<br><br>Chris