PDA

View Full Version : ATV Diff Lube


Conor
04-19-2007, 06:36 AM
For teams using a cam and pawl limited slip out of an ATV, what type of lube are you using for the diff? In one of the Carrol Smith books, he mentions packing a cam and pawl full of moly. Is it an option to use 40w90 gear oil, or is it best to use a moly lube?
Conor
04-19-2007, 06:36 AM
For teams using a cam and pawl limited slip out of an ATV, what type of lube are you using for the diff? In one of the Carrol Smith books, he mentions packing a cam and pawl full of moly. Is it an option to use 40w90 gear oil, or is it best to use a moly lube?
Dallas Blake
04-19-2007, 09:16 AM
My experience with ATV diffs (not in FSAE as we use the Torsen) has been 80-90w gear oil for the diff except for the Polaris front diffs which run a very thin oil
Conor
04-19-2007, 12:34 PM
I apologize, I intended to say 80w90. That seems to be the standard, but I'm curious as to why Carrol Smith refers to packing the cam and pawl diff full of moly.
drivetrainUW-Platt
04-19-2007, 08:07 PM
If you have any doubt of what to use, look it up in the manual for the ATV. Any dealership can tell you this as well.
Chris Allbee
04-20-2007, 06:39 AM
Differentials are essentially friction devices. I can't be certain as I haven't run any tests, but I imagine Carrol Smith's remarks were of the intent that the moy would keep its integrity better under high load conditions over long periods of time and with large amounts of heat build-up (within reason of course). this would in turn provide more consistent behavior out of the differential over the course of a race. Again, can't be for certain on that, but that's my 2 cents.
Conor
04-20-2007, 06:48 AM
Thanks for the help guys. I'm gonna get a hold of the manual and see what the stock diff is supposed to use, but if it is moly, I wonder if there would be any advantages to running 80w90... ?
Bete Noir
04-23-2007, 07:17 PM
The viscosity you mention 80W90 is merely a nominal viscosity. The actual viscosity is a function of temperature as well as material. If the diff is expected to run very hot, a more viscous lubricant must be used. In the event that temperature lowers viscosity to unacceptably low values, then a friction modifier or HP additive is necessary to minimize contact wear. The alternative is to use a much higher viscosity with the resulting viscous drag that comes with it.