I have a 1983 CJ7/258/T-999. I want to swap a T-5 into my Jeep. The T-999 is getting weak and I want to finally have a standard with an overdrive. Do I need to change the front & rear ends to complete the change-over? I don't have a T-5 yet to swap in, I'm trying to find out what this job is going to entail.