Listen to RWH above. He specializes in this type of work. I don't.
Maintenance is king on these suckers. And if done right and kept up the value will increase or at the very least you may get part of the money back out of it.
I have owned my HMMWV for about 15 years and have a love- hate relation ship with it. I bought mine when they were a rarity so I paid a bunch for it.
I'll probably never be able to recoup what I have in it.
At times I don't know why I still own it.
But it keeps me out of the bars and has allowed me to work on my attitude adjustment skills.
Your reasons may vary. Maybe it's therapeutic , maybe to spend time with your son or even daughter working on a project together.
What ever it is you will soon find out that the military acronym and the true meaning of HMMWV is.
I swapped out power pack whole a few years back and used a aftermarket controller because I didn't want to separate body from frame and change main body harness. ( I'm too cheap)
After 3 years or so I finally bit the bullet and separated it. ( could have used that money)
Once I did that I was committed. I changed out everything.
A arms , bushings, Ball joints, Hubs, half shafts, Wire harness, fuel tank, Half shafts, front and rear diff's, I had done the parking brake upgrade with the body on. (that would have been a whole lot easier with body off)
I cut the floor and installed the inspection plate over the fuel gauge sender.
I insulated the underside of the body as well when it was off.
I worked on it on the weekends and it took me about 5-6 months .
I drove it in a 4th of July parade and then parked it in the garage.
I have more to do to it but after 5-6 months of looking at it every F'n weekend I'm taking a break for a bit.
Take your time. If it's worth doing , do it right .
Best of luck on your upcoming project.