Any Interest in Chevy Express 10.5" Axle for Upgrade?

[valvegod]

Anyone interested in a heavy duty 10.5" rear axle assembly (non locking diff) for their 2013-2018 Chevy Express 3500 Roadtrek? I picked up 2 which are basically new take outs (less than 5,000 miles) from a local GM program that I buy through. I am using 1 for my 2018, and have an extra. I also have access to 3 more. They are complete with rotors and sensors and calipers. This is the 3.54 ratio compared to the 3.42 that is in the 9.5" axle. You will need to have a dealer or programmer reflash for the axle ratio change which is a minor cost. These are impossible to find, as I have been looking for 2 weeks and all the salvage yards have them listed wrong and there is only 1 available in the country that I found. $1,000.00 plus freight or pickup in SE Michigan. I can also have the Carrier upgraded with an Eaton TRUETRAC if interested.

[booster]

A point to note is that those ratios would be for the newer 6 speed models, not the 4 speed ones before 2010, which would take a 4.10 or 3.73 ratio. You could do a gear change, but I think you also would have to do a carrier change for that much ratio change.

[cruising7388]

Originally Posted by booster

A point to note is that those ratios would be for the newer 6 speed models, not the 4 speed ones before 2010, which would take a 4.10 or 3.73 ratio. You could do a gear change, but I think you also would have to do a carrier change for that much ratio change.

What does this axle change accomplish?

[valvegod]

4:10 and lower take the same carrier so no change required if using on earlier models with 4L80e 4 speed.

[booster]

Are they still using the Dana 70s and gov-lock if a locker?

[valvegod]

To my knowledge they have not used a Dana in a long time my 2003 has an American axle 10.5 and these are all American axles. I do not know what they use from the factory for a locker these are open. Updating mine to a Eaton Trutrac

[booster]

By 2004 they appeared to be using the Dana Super 70, or 70s model on the axle tag. I personally saw one in a 2004 anniversary edition a while ago that still had to OEM tag on it. I bought a 10.5" from a bone yard in Maine for our 07 190 and it was a Dana. When I was looking for an axle, I found several references to AA axles in the vans, but never found one in my searches. All the 10.5" ones were Dana 70s on ebay and on Hollander. The previous version Express that had the drum brakes in the rear used a 10.5" that was said to be a corporate version, but it also could have been a rebadged AA.


If you have access to the parts books, it would be interesting to find out what came in what years.

[cruising7388]

Originally Posted by booster

By 2004 they appeared to be using the Dana Super 70, or 70s model on the axle tag. I personally saw one in a 2004 anniversary edition a while ago that still had to OEM tag on it. I bought a 10.5" from a bone yard in Maine for our 07 190 and it was a Dana. When I was looking for an axle, I found several references to AA axles in the vans, but never found one in my searches. All the 10.5" ones were Dana 70s on ebay and on Hollander. The previous version Express that had the drum brakes in the rear used a 10.5" that was said to be a corporate version, but it also could have been a rebadged AA.


If you have access to the parts books, it would be interesting to find out what came in what years.

I understand Hondo's 4WD conversion on his 210 making practical use of the increased capacity of a full floating axle but if using the coach under conditions for which it was designed, this seems to me to be an expensive and laborious conversion to address a non-existent problem. How many people in the entire history of Roadtrek Chevy production have suffered rear axle failures?

[booster]

Originally Posted by cruising7388

I understand Hondo's 4WD conversion on his 210 making practical use of the increased capacity of a full floating axle but if using the coach under conditions for which it was designed, this seems to me to be an expensive and laborious conversion to address a non-existent problem. How many people in the entire history of Roadtrek Chevy production have suffered rear axle failures?

Our 9.75" axle failed twice within the first 20K miles in our 2007 190P.


With the full floating 10.5" axle our rear hubs, wheels, and tires also run much cooler with less pressure change from the extra heat.

[cruising7388]

Originally Posted by booster

Our 9.75" axle failed twice within the first 20K miles in our 2007 190P.


With the full floating 10.5" axle our rear hubs, wheels, and tires also run much cooler with less pressure change from the extra heat.

The two failures were identical?

[booster]

Originally Posted by cruising7388

The two failures were identical?

Yep, both pinion bearing failures. GM did a complete rebuild under warranty on the first one, which failed again just out of warranty.


There seemed to be a bunch of unrepairable 9.75" axles in the 2007 time frame. We have run into 3 other Roadtreks of that era that had similar issues, and all of them required replacing the entire axle to finally fix. The best I have been able to find out is that it is likely that the axle housing themselves were bad, possibly from improper aging before machining


Looking at the design of the 9.75" axle, I am actually surprised we don't see a lot more of the failures in the heavy Roadtreks. The Dana 60 has been beefed up several times to get up the 6040# capacity that it is currently at on the Chevies by using things like a structural cover that works kind of like a stud girdle with no gasket, and going to wheel bearings with no inside race. That is not a typo, no inside race for the wheel bearings. The are straight roller bearings where the inside of the rollers are directly on the axle shaft. Eat a bearing and you destroy the axle shaft also. Like many semi floating axle assemblies, all the cornering forces are transferred back to the differential housing and absorbed by the carrier bearings as the roller bearings are unable to pick up any side loads. The axle shafts also carry all weight load and driving force, where in the 10.5" full floating axle, the weight is carried by the axle housing and the axles only see the driving force.


The wheel bearing design is likely why the rear hubs on Roadtreks can run so hot, and heat up the wheels and tires, increasing rear tire pressure more than is desirable. With the 10.5" axle we currently have in place, many times the rear hubs are actually cooler than than the front hubs, where they used to be much hotter. Tire pressure changes front to rear while driving are now very consistent and the same amount, so handling stays more consistent, too.

[cruising7388]

Originally Posted by booster

Yep, both pinion bearing failures. GM did a complete rebuild under warranty on the first one, which failed again just out of warranty.


There seemed to be a bunch of unrepairable 9.75" axles in the 2007 time frame. We have run into 3 other Roadtreks of that era that had similar issues, and all of them required replacing the entire axle to finally fix. The best I have been able to find out is that it is likely that the axle housing themselves were bad, possibly from improper aging before machining


Looking at the design of the 9.75" axle, I am actually surprised we don't see a lot more of the failures in the heavy Roadtreks. The Dana 60 has been beefed up several times to get up the 6040# capacity that it is currently at on the Chevies by using things like a structural cover that works kind of like a stud girdle with no gasket, and going to wheel bearings with no inside race. That is not a typo, no inside race for the wheel bearings. The are straight roller bearings where the inside of the rollers are directly on the axle shaft. Eat a bearing and you destroy the axle shaft also. Like many semi floating axle assemblies, all the cornering forces are transferred back to the differential housing and absorbed by the carrier bearings as the roller bearings are unable to pick up any side loads. The axle shafts also carry all weight load and driving force, where in the 10.5" full floating axle, the weight is carried by the axle housing and the axles only see the driving force.


The wheel bearing design is likely why the rear hubs on Roadtreks can run so hot, and heat up the wheels and tires, increasing rear tire pressure more than is desirable. With the 10.5" axle we currently have in place, many times the rear hubs are actually cooler than than the front hubs, where they used to be much hotter. Tire pressure changes front to rear while driving are now very consistent and the same amount, so handling stays more consistent, too.

The axle evolution on the Chevy is perplexing. The G30 platform offered a Dana 70 option. Even on the 3500 Express, in 2004 Roatrreks that had the trailer option included the Dana 70. But currently, I guess there is no way to get a Dana 70 on a SWD Express platform. I wonder if the lower production cost of the Dana 60 isn't more than offset by the warranty claims for failures. Aren't these failures covered by the 5 year/50k drive train warranty?

I also wonder if part of the reason for the hotter hubs you report is the prevalence of the negative offset aluminum wheels that aggravate the bearing load.

Did Chevy actually determine that the full rating for the Dana 60 is actually 6040 or did they just throw that in to match the tire rating for the 245 tire?

[booster]

Originally Posted by cruising7388

The axle evolution on the Chevy is perplexing. The G30 platform offered a Dana 70 option. Even on the 3500 Express, in 2004 Roatrreks that had the trailer option included the Dana 70. But currently, I guess there is no way to get a Dana 70 on a SWD Express platform. I wonder if the lower production cost of the Dana 60 isn't more than offset by the warranty claims for failures. Aren't these failures covered by the 5 year/50k drive train warranty?

I also wonder if part of the reason for the hotter hubs you report is the prevalence of the negative offset aluminum wheels that aggravate the bearing load.

Did Chevy actually determine that the full rating for the Dana 60 is actually 6040 or did they just throw that in to match the tire rating for the 245 tire?

The previous generation of Express van used the "GM corporate" 10.5" axle, which apparently is the same thing as an American Axle unit. I think AA was spun off of GM someplace along the way. They are also listed as used from 2003-2009, but I have never seen one, on Dana 70s. The main difference between the two generations of axles is rear disk brakes on the newer ones.


It appears that in about 2010 GM brought the axle building back in house, so the 2010 up axles may be GM built, or could be AA axles also.


If the Express van AA and GM corporate axles are made like the other versions, they are every bit as good, and probably better than the Dana 70s axles. They have a "bombproof" reputation in the off road crowd, from what I have read. The biggest plus of them is having an out the front removal pinion setup for easy pinion bearing setup and repair plus better pinion support.


As for the rating of the Dana 60, it appears that Dana made some upgrades to the normal Dana 60 to get to the 6040# rating of the 60s. The ring gear is 9.75" instead of 9.5" and they added a structural cast steel rear cover to strengthen the case. Maybe larger axle tubes. I think the weird no inner race wheel bearings may also have been in that change. IIRC, the original Dana 60 was rated at something like 4500#.


I do think that the too large of an offset wheels contribute to the overly hot rear hubs, especially with the less than stellar wheel bearing design. I also think that once you get to a one ton truck, semi-floating rear axles just don't cut it and a full floater should be used.