I ran across this thread when I was looking for information as to what axle Roadtrek uses when you get the trailer towing package. I still don't know what they use, however, but can shed a little light on some of the questions in this discussion, as we have been looking at an axle swap.
The Dana 60 in the Chevy Roadtreks is actually a Dana Super 60 semi-floater. As near as I have been able to find out, the main differences are two extra bolts in a beefier rear cover (12 bolts compared to 10) to make it more structural, and bigger tubes and wheel bearings. Maybe some other internals, but hard to say.
The information on actual axle maximum load is very hard to find and sketchy, but it looks like most are saying right around 6K pounds, so the 6082# on the Chevy rating plate is pretty close and is equal to the tire maximum rating.
We hear of failures, but not all that many, I think, so they are getting by with the axle, although it was originally beefed up to take it from a 1/2 ton axle to a 3/4 ton axle, and is now on fully loaded 1 tons. The wrong offset wheels, if you have them, also put more load on the wheel and carrier bearings. Again, though, less failures than I would expect----except for us and some other 2007 vintage folks I have read about. There was likely a bad run of the big cast housings in that time frame, which caused early failures. Ours was rebuilt by GM at 5600 miles with all new guts, including gearset. We are now at 27K miles and it is getting a little noisy when the power is on. I wasn't all that concerned right away because all rear drives whine a little here and there, but when I had it in to be aligned, the tech drove it and said he thought the pinion bearings were going, or were loose, because it whined at all speeds when accelerating. I took it to a couple driveline guys and they said the same (as does the factory manual). They said if it were only at particular speeds, it would not be bad, but at all speeds probably is. Didn't know that. The oil is staying clean, so it is not at immanent death mode, but not pristine either. We have been kind of paranoid after the first failure so early, and that other 2007s that I have heard about got rebuilt twice under warranty, failed again and were replaced with a complete axle, housing and all, that finally fixed them permanently.
As near as I have been able to find out, GM used three axles in the one tons. The Dana Super 60 semi-floater 9.75" ring gear, the Dana Super 70 full floater 10.5" ring gear, and probably an American Axle (often called GM corporate) full floater, 11.25" ring gear (I have not been able to actually find one, though, and it may only be on cutaways). It may also be a Dana 80 in the 11.25".
Our fear is that we will have a failure on the road, and have to put $1500+ in the one we have, and it will probably still fail again besides. Since we have higher capacity tires and suspension, it made sense to look at getting the axle capacity up also, rather than just getting another Super 60 to put in complete. Most sources I found put the capacity of the Dana Super 70 at about 7500#, so that looked pretty good to me. The driveline guys I talked to all said that at 6000# load, you should not be on a sem-floater, and didn't really have much bad to say about the Super 70. The did prefer the 10.5" GM corporate that was used in previous models, for some nice features and aftermarket parts availability, but said both were extremely durable in a one ton.
When I started looking for a used, complete Super 70 with 4.10 gears, it became obvious they are a bit rare, and at least 50% more cost than the 3.73 versions in most cases. There is a carrier gear split at 4.10, so if you get a 3.73 and try to change gears, you can just put in a rear gear and pinion set. That wouldn't be bad, if you were going to add a posi unit you would need to change the carrier also, but it turns out there are no real "streetable" posi units for the Dana's in the aftermarket. All that you can get are the old plate clutch, always engaged, units that are so wicked scary on the slippery roads, or a very expensive air, electric, or cable locker. What is very interesting is that GM put auto lockup differentials into the Dana differentials. That lockup differential is made for them by Spicer, but you can't buy them outright. If you have one, you can get service parts from GM for them. Long story short, searched for a Dana Super 70, 4.10 gears, with the GM posi, which is really an auto locker called Gov-lock and only engages when you need it, and never about 20mph, so it very safe for the street.
It is interesting the most of the Dana 70s I found were cheaper than the Dana 60s, so they must sell few 70s and lots of 60s, which makes sense.
We now have one on the way that will get here in about a week. 84K miles on it out of a 2004. I don't have the setting tools and bearing and seal drivers for this style, so will take it in to have new seals, bearing inspection, and setup check. At 84K everyone said the bearings and gearset should be fine and good for 200K more minimum, so we will see, but it 10 year old, so seals are for sure.
Indications are that it is close to a drop in, although a very heavy one. It will need different rotors to clear the big floater hubs, but the driveshaft is listed as the same on the interchange charts, so we will see. Might need different u-joints, but couldn't find that out. All the other brake parts look to move right over.
Hopefully, this will put our insecurities to rest about recurring issues, and maybe the locker will make us a bit more mobile around the beaches and forests.
