I'm not trying to solve a parking brake problem ....but, I was thinking of going to a 5-speed (seems like that's a thing to do now) and if so would need the late style rear axle with the emergency brake at each hub. I get up and cruise interstate easily at 65+- with my original set up now, but my rear diff is creating a loud (to me) roar and a decent amount of vibration that I don't think is normal when there is pressure (throttle) on them. I had that drive shaft balanced and I know they are good but I rebuilt the 3rd member but I just can't get it right backlash etc.... without the correct tools and know how. I checked with a couple of known companies for drop in rebuilt 3rd members and no one has them and are having a problem sourcing 3.70 ring and pinion is for a rebuild. My 40 is an early (April 1980) I just need a drop in solid rear third member that is set correctly so I can just....DROP it in and go.
I know going with a 5 speed was going to cause and cost a bunch of

especially since I have a OEM PTO winch and gear box.