This paper presents the AGMA925-A03 scuffing risk predictions for a series of spur and helical gear sets of
transmissions that are used in commercial vehicles ranging from SAE class 3 through class 8. Contact
temperature was calculated for 50 spur and helical gear sets. Limiting scuffing temperatures using 2 mineral
and 3 synthetic gear lubricants were determined from FZG scuffing tests. The risk of scuffing was then
assessed comparing the contact temperature with limiting scuffing temperature. The results were compared
with field and warranty data, and dynamometer test results. A good agreement was obtained for all cases.
The agreement between prediction, test results and actual usage provides confidence in the predictor of
scuffing risk for gears in commercial vehicle transmissions.