hey guys i was just wondering i just replaced my ujoint on my van cuz it vibrated like crazy. Now i just want to make sure there is enough fluid back there so i was wondering just in case there isnt enough what king of or what is the best oil to use for the rear end.

Owner's manual will have the best answer for you, but in general an 80W-90 gear oil is the norm for the average truck. Heavy-duty hauling may require a step up to 75W-140 or thereabouts. Any good API-certified lube should be acceptable. I prefer Valvoline synthetics, but I'm currently testing Lucas Oil heavy-duty 80W-90 in my hauler. Everyone here will have their own favorite...Amsoil seems to have a good following in here and other forums. I've also read that synthetics are not recommended for diffs older than 1998.

Also check if your van has a limited slip differential. These may require a special "friction modifier" additive. Your RPO code sticker, usually found in the glovebox, will show you everything it came with from the factory...G86 is a limited slip while G80 is positraction or locking differential. Only the G86 may have the need for an additive.

To check the level, there is a plug on the passenger side of the diff housing with a square key. Remove that and dip your finger into it. If you feel the fluid right at the hole's bottom edge, the level is good. Van should be parked level when doing this. Add more through the same hole. A rubber tube attached to a lube bottle's nozzle works for me. Add slowly so it doesn't squirt back out...it should just ooze out of the hole when it's full. Hope this helps!