[JJram82]

So the manual calls for a 15/40 on both the zforce 500 and 800 I run that weight in my 6.7 Cummins so is this the same

[Webb2018]

 It seems most people are using 5W-40. It needs the JASO rating. A lot of us use diesel oil like Rotella T6.

[REDRIDER]

I use Rotella T6. 

[impact]

I also use 5W40 synthetic Mobil 1 in my 500. This is not a wet clutch system though.

It covers the colder temperatures we have now started for the next 4 months.

[Hrc630]

Rotella T6 is perfect for our engine.

[SDHarleydad]

Rottella T4 and T6 are JASO approved for the wet clutch system

[Kenai]

Do not use t4   made that mistake and clutch slipped for an hour till I could get back to the truck and head home and change it

[glenlivet]

Do not use t4   made that mistake and clutch slipped for an hour till I could get back to the truck and head home and change it

Odd, I run T4 and it's just fine. Same rating as T6 but not synthetic. No slip with my wet clutch equipped 800.