I'd say a G52 or G54 as the forward shift W series have a 6 bolt shifter base that has both the trans and t-case shifters on the same base. The G series use 2 seperate plates. Also, I would suspect it's not an R as the detents for the trans shifter on your trans are more towards the back where the R series detents are more towards the front. Your drain plug should go straight down and not to the passenger side as the R series trans does.
