I’m getting ready to change the fluid in the differential on my 2001 Ram 1500 with the 5.2L engine with close to 100K miles. This will be the first time I’m doing it since acquiring the truck. Upon looking in the Haynes manual, it states I need to put 8 oz of friction modifier while doing the service. I know it takes 2.5 to 3.0 quarts of gear oil to do the job. Upon reading the label on the friction modifier tubes, it states that a 4 oz tube of friction modifier is good for up to four (4) quarts of gear lube. Should I just stick with the full 8 oz like the Haynes manual states? That would be the info I would be more inclined to go with. Any suggestions?
Also while re-assembling the cover, do I put RTV on both sides of the gasket or do I just stick to the Diff. side for the RTV sealant?