Hi, John, Go to teck tips for 3:55 ring gear instalation. If you are in that deap, it is a good idea to install the 3:55 ring gear set and get the installation package with new bearings and seals and gaskets. Thats what I did on my 49 and I am happy with it. On a Canadain truck you will have to have a machine shop slot the new ring gear mounting holes to match the carrier. Take in the old ring gear with the new one when you go to the machine shop and while you are in there install a new front bushing. PS My boss at work has a saying - In for a dime, in for a dollar.