Chief Transmission and Primary Oil

[chief39]

Hi everyone I was just doing my spring service work on my 39 Chief and was wondering what oil everyone uses in their Chief Trans/Primary cases. Thanks for any and all replies. Hope everyone is making good use of the recent good weather.

[tomfiii]

I've used straight 30 weight non-detergent and 20w-50 sport transmission oil synthetic that is made to use with clutch and noticed no difference .

[RonH]

I am using straight 50 weight in the trans and primary, I live in Central Florida.

[pisten-bully]

30W non-detergent here (gearbox and primary connected)

[Tobydog61]

Harley Davidson Formula Plus. Made for primaries and wet clutches.