Your '07 chassis came with the self alligning bearing already, you should check to make sure it's still in there.
The 45T was the most common Slip Gear, not saying it can't be a 43T but all the '07 came with 45T. I have several slippers other than the 45T so I know they are out there but I am thinking if someone has a 43T they likely hung on to it and put the stocker back in there.
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