Originally Posted By: dailydriver
Originally Posted By: MolaKule
Originally Posted By: redbone3
I found this on the Torsen website:
Torsen for GM vehicles:
Is it true that the Torsen unit in the production Camaro needs the GM modifier added? Top of the Page
GM issued a technical bulletin adding modifier to the rear axle oil. This was done to quiet what we call a "Rusty Screw" noise that we heard in a very small percentage of vehicles. This does not happen in all cases, however to address owner's concerns we asked that the modifier be used in all instances to insure that the driver would not get this noise. When replacing the fluid it is at the owner's discretion whether or not to add the modifier. Elimination of the modifier does not affect durability of the differential.
Does the GM tech bulletin mention a part number such as GM #88900330 or some other "modifier?"
The description for this product says:
Quote:
The additive reduces friction between your limited slip or positraction differential friction plates to eliminate the annoying chatter that is common with these types of units. This Chevrolet Performance limited slip lubricant additive not only quiets your rear-end, but it can also aid in your differential's ability to apply and release the clutch smoothly, creating a more pleasant and predictable power delivery.
There are no clutches in the Torsen.
My guess is that it
slightly reduced the case to outer worm gear friction, just enough to eliminate the noises.
I remember this TSB, even though it did NOT affect me since I had already changed out the T-2 for an Eaton carbon clutch pack Posi (about a year after I bought the car), which DOES need some FM to not 'rusty screw', or chatter around slow, parking lot speed turns, or no torque applied, coasting turns.
You could be right. Maybe I am trying to over analyze this thing, something I have never done in my life, of course.
But if you look at the simulation, torque forces are being transferred purely across the gearing, so the only thing left in my view would be the bearings in the gear carriers. AKA, reactive forces causing wobble in the bearings that could be dampened out by the polymers in FM.