FWIW ...
The OP should check out our Tech Tips for the article on swapping out the center section of the Eaton HO-52/72 rear axle for better speeds
It can be found hereAssuming, of course, the OP still retains the 3600's original HO52 rear axle.
Anyway, getting better "drive-ability" (whatever THAT means ...) is way easier for 3/4 and 1-ton AD trucks than for the 1/2-tons. I can cruise on the highway in my 3804 at 65 mph, as well as cruise around town. All I did was change out the center section in the rear as per the article (we actually wrote that article from the experience gained in doing my truck). I retain the original SM-420 trans (1st gear becomes a real 1st and not just a granny 1st. Still unsynchro'd though ...), the original everything else. While I did upgrade to a 261, the mod works great with a 235 as well. The gearing change is a little on the tall side for the original 216 that was in my truck.
I run 17 inch wheels, though... The steering works fine (my truck is low mileage and garage kept since new). I still run Huck brakes (they take more care and feeding than Bendix, and you have to drive defensively). My gas tank is still in the cab. I don't smell gas and I've smoked plenty of cigars in my truck. I've run this site for 30 years now and I have yet to hear about an AD blowing up.
Just my opinion, but I think 3600 and 3800 owners sometimes get carried away and make this harder than it needs to be. Trying to figure out best gear sets for a T-5, figuring out custom drive shafts, tranny mounts and bell housing adapter .... yikes. So while all these guys (with 1/2-ton experience... just sayin') are telling you all these crazy gyrations to go through (if you get this T-5 you have to do this, that, and all the other things... and its still a car tranny, by the way ...) ... Just switch out the rear axle center section and be done with it. Easy peasey. When I want easy, comfy driving experience, I take Miss Peggy's VW.
I know, I know ... there are some real T-5 die hards out there... and Jay ... I love you like the brother you truly are to me .... but .... T-5s may be the cat's butt for a 1/2-ton, I'm just not that convinced they are all that and a bag of chips for 3/4 and 1-tons.
"Rock crawlers LOVE T-5 trannies!" Said no one ever.
If the OP stays with his original brakes, just go through them and make sure they're good for highway speeds. And if you don't already have them, put some seat belts in your truck.
