M
MoonSailer
My volvo transmission and V-drive call for 30 weight oil. I've been using multigrade oil the same as I use in the diesel engine. 15w-40 My brother said that the multigrade oil could cause seals to swell and cause overheating. Has anyone ever had this problem?? single grade non-detergent oil is relatively rare but I'll find some and pump out the multigrade if this is required.