I know I am contradicting what some of my friends are saying here on two parts of this thread and normally I would just sit here and shake my head and post nothing. But I have some substanial experience with deuces in off road and long distance on road driving and would like to offer my observations and opinions. First, disconnecting the front tandem axle will never get you stuck on a speed bump in a parking lot, but taking the intermediate driveshaft out to disconnect the rear tandem sure will. This is from experience. I have done it both ways over the years and you can go a lot of places with the rear tandem and front steering axle doing the work. When we crossed the US in 2008 we went all the way to the Pacific and drove the trucks out on the Beach just north of Newport Oregon, I had no trouble in the sand or coming back up to the road even with the M105 trailer on the back.
Second, I will admit that I am not a mechanical or automotive engineer, but, when you disconnect one side of a differential and leave the other side connected , and there is power transmitted through that differential to the rear axle, wouldn't that cause the spider gears to spin a lot? If both sides are disconnected on the forward tandem axle, then the power transmitted through to the rear tandem axle may not force the spiders to be spinning?
To my friends who have posted already, don't get mad at me, just tell me where I got the wrong idea, to the people who are new here and not "deuce experienced" weigh the comments and do what you want, we all have tried or own ideas plenty around here. JT out