I tow a boat with my JGC, so the manual staes to use a heavy duty 75w-140 in the rear differential. The only one around was this quaker state stuff.
It is clear in colour and can be loaded into the rear differential with one of those boat outdrive pumps , about $10 at your local car or boat dealer.
The differnetial was easy to open , with only a rubber plug to open the thing up.
Took out the old fluid and then pumped in this stuff , about 1 3/4 liters before the fluid started to come out , oh and one thing I did not know -- add the friction modifier a 4oz bottle 120 ml from your dealer $5 mopar so as to make the LSD limited slip differential work --- back differential only unless you have quada drive then in both difs. The front diff uses 75w-90 synth by motomaster
mine is selcta drive with lsd rear.
So far it's worked great , towed my boat with no problems and am quite happy with the product -- I'll report back in about a year with an update
June 2008 -- stuff still running good in the diff, maybe I'll do a second time , if I get round to it