"Let me clearify a bit.
If wh
"Let me clearify a bit.
If what You have works, keep on using it. If you do a 'major' repair, including cleaning out the drive from old oil, why not up grade. The reson that the DP drive recomended GL5 oil was only that Volvo finally discovered that there are better oils available. The reson for using 'engine oil' was more of 'convenience' for the customers. The DP drives has in fact less stress on the critical parts (pinion and pinion bearing) than the single prop drives. Lubrication wise the GL5 oil is better as it is intended for 'lubrication of spiral cut gears'. Where it may create a problem is in the shifting system, clutch cone. The cone may not be able to break the oil film and create the friction needed for engagement. With the newer syntethic oils on the market the oil film has become so 'strong' that this problem may even occur when using engine oil, GL5 may as well be used!"