Your Fleet isn't limited slip unless you (or someone else) installed it. G80 (ltd slip) wasn't an option on Fleetwood because it has traction control. It should be filled to the bottom of the fill hole with 80w90. If you did install a clutch or cone posi (Eaton or Auburn), you would put in one bottle of GM posi additive, then fill the rest of the way with the 80w90.

 

Thank you, Jason.

 

I was checking oil level inside of the differential and because the driver side of the vehicle was raised, some 3-4 oz of oil were lost as soon as I removed the plug. The level was most likely correct. Should I compensate the missing volume or leave it alone?

 

Thanks. I can raise only one side at the time. Is it okay to overfill a few ozs? This time I wil raise the passenger side to get to the hole.

If you end up with the axxle tilted higher than level to fill, then just go ahead and overfill, and then briefly lower until you eyeball that it's level to let the excess drain, then raise back up as needed for access to install plug.

 

Put it on level ground (or on level stands/ramps), and fill until it comes out the hole. With the stuff I told you about in post #2.

 

Put it on level ground (or on level stands/ramps), and fill until it comes out the hole. With the stuff I told you about in post #2.
[/QUOT] Thanks. I can raise only one side at the time. Is it okay to overfill a few ozs? This time I wil raise the passenger side to get to the hole.

 

That was my plan of action. )) But... the diff takes 2.25 qtr of oil. Is missing volume of 3 ounces really critical? I have to make another 600 miles before I am in a position to adjust the gear oil volume. Hopefully, I will not hurt anything.
If overfilling is okay, I would skip extra lowering-raising, which is not fun with the jack in the trunk.

 

Scissor jack. Ok, that answer's a big question mark. Overfilling (I've read) sloshes fluid to a level that creates foaming, and unnecessarily increases parasitic loss from friction. That given, I'd conjecture that the alternative of running 3/72oz. = 4% low is much preferred. Especially using a scissor jack.

 

96 Black, good point!

 

The twilight sentinel is intermittent, but I can turn lights on manually, so I will leave it there for now.