I've been looking all over the net and the ih8mud website for the stock axle ratio for a 1991 HDJ81 with a 5 speed manual transmission, I just acquired one the other day. I am going to be selling my 1990 HDJ81 with automatic transmission, with Wholesale Transmission Extreme Valve Body. Next week I am swapping a bunch of gear including my factory e-lockered axles off my 1990 onto the new truck, the lockered axles presently have 4:88 gearing and I figure with the 5 speed I will go back to 4:11s but I don't know if the ratios are the same for both automatics and 5 speeds.