I'm not sure of which slots you mentioned but the shift rail guides had slots for lubrication. Oil was actually supposed to flow or leak slightly around the shift rails on the old stuff. I wouldn't worry about those holes on the ends of the rails. The shifters as you have weren't much of a problem but the rails on the T-90 tranny (early CJs) are prone to heavier leakage in the rear (no seals). The tail shaft on the Spicer 18 was a leaker also.

I was just curious as to what they were for or originally used for. <img src="/forums/images/graemlins/kewl.gif" alt="" />