2007 Express 3500 Full Floater Rear Axle Swap Questions

[youngnretired]

We just returned from our east coast trip. While in the beginning of our trip, we stopped at a scale and found that we were 10,040lbs, 440lbs over GVWR of 9600lbs. Upon return, we unloaded our gear from the van, filled the fuel, water and propane tanks and my wife and I went to get a "base" weight. With only our cooking gear, chairs, mats, etc in the van and without any clothes, food or tools/gear for even a night on the road, we weighed 9620lbs - still overweight.

Today, I discovered a full floater single rear wheel axle in a 2003 3500 express van (cargo van, not a box van) in a local salvage yard and I'm considering pulling the lever and buying it to swap into our 2007 Roadtrek. It would cost $420 to purchase and that van has 272k miles on it. It has not been in the yard long because the brake rotors only had slight rust on them. I will call GM on Monday and have them decode the VIN to tell me what gear ratio it is, but I'm guessing it's a 4.10, but it's a guess.

I believe that this should be a 100% bolt in swap, but the part I'm not certain about is the drive shaft/U-joint matching up from the 2003 and 2007 chassis' and what may be different from that perspective. I also realize that this has 272k miles on it, so the bearings and gears may be shot, but it's sitting on the ground no way to pull the diff cover to verify any condition.

Just wondering what others thoughts are on doing this swap and what the fuel economy differences may be between the 3.73 that's in the RT now and a possible 4.10 ratio. I realize that the speedometer will need to be corrected, but I believe this is just changing something in the computer. If anyone knows, please comment.

Thoughts and comments from others please.

 

[youngnretired]

Funny. I just looked at the full picture of this side of the van before I cropped it, and it says "3.73". I think I have my answer on gear ratio.

 

[booster]

I have done the swap personally in my garage at home. Not all that difficult, but very heavy stuff to deal with. One thing to remember is to mark the orientation of your current yoke when you remove it from your axle and use it for the new axle, assuming you can get the junk yard one off. I had the guy do it when he set the lash and pattern as he had the special, huge, puller to do it. My puller broke trying.

You should be able to get the ratio and if it is a locker off the RPO code on the van or the yard could take a pic of it for you and send it to you.

273K is a lot of miles even on these axles. The rear axle guy I had set the lash and pattern as I couldn't get it right said they go 300K+ with good care, so it is nearing full rebuild time which would cost much more than buying an lower mile one.

I have seen 150K 3.73 non lockers for under $300. The bearings in those are probably fine, as mine were, at that mileage and a gear change would add the cost of the ring gear and maybe carrier bearings depending on how they come out.

With that load, you need to get more capacity on the tires and axle but you will still be illegal if stopped or in a crash, so be aware of that.

There currently are two sets of the 17X8 GMC Sierra wheels on marketplace relatively close by. $200 for a not great looking but should clean up pretty easily for paint, and another at $250 that say never saw salt and just appear to clearcoat clouding and cracking. There is also a set of the Chevy version for $450 that probably could be used as is OK and come with center caps and lug nuts.

Here is a link to the post that describes the axle swap that I did for our van, which did have a 4.10 and locker.

10.5" axle install link

 

[youngnretired]

I've searched online for several local salvage yards, and I find that they are asking $350+ for their axles and they are all over 200k miles. The $420 breaks down to $350 for the axle, $50 to pull and $20 tax, so I'm not finding any bargains. This particular vehicle must have had the center caps on the wheels as the hubs have zero rust on them and from what little I could see underneath the van, the axle didn't look too bad.

I'm 95% sure I won't tackle the axle swap. I'll pull the caps and diff cover and inspect, but this is likely to go to the local mechanic 1/4 mile away for him to do the swap and change the gears/bearings if things don't look so good inside. This will probably only take him 2-3 hours on a lift to swap the axle. That $250ish seems a better deal than me laying in the driveway for 2 days fitting an axle under the van. As of now, I don't know where I would locate jack stands on the frame to support the van to drop the axle. I swapped both axles on my old 84 Chevy half ton some 30 years ago, but that was an easy swap with a readily accessible access to put jack stands on the frame.

I'm going to stop at the mechanic's tomorrow morning and have a chat with him and get his take on an axle with 272k miles and his interest in swapping it out.

 

[booster]

I just did a quick search and stumbled on a killer deal only 6 miles from me if it is really what the search was for.

$250 for a 10.5", 4.10, with a G80 locker. 166500 miles. Even if it cost you $300 to ship, if they ship, you would be money ahead. The listing is on car-part.com and also on the yards website search which appears to use car-part search. It came up as a 4.10 and locker in search and does say G80 locker in the listing so the 4.10 is the only question, plus of course, if they still have it. Even if a 3.73 it is still a good deal as the locker usually adds at least $2-300 from what I have seen as they are rare in the Dana 10.5"

car-part with seach link

I searched 2005/Express 3500/rear axle assy/zip 55449 then fine tune box 4.10 without active control.

It is at this yard in Ham Lake Mn named Jellison Auto parts. I have been there in the past and good place.

Jellison link.

If you came and picked it up you probably could get a set of the aluminum wheels that I mentioned at $200 or $250 along the way. I just looked and it is only a 300 mile trip from Green Bay so a one day trip would be possible. We make that drive nearly every year, but to Gogebic and Copper harbor so very familiar with it.

on edit, now a set of the GMC aluminum 8x17 wheels in Scandia, MN just showed up on Marketplace at only $100 and appears to be for 4 wheels but doesn't specifically say. Scandia is about 30 miles NE of Minneapolis fairly near the Wisconsin border.

Give them a call and see what they say, if you are interested.

 

[youngnretired]

Booster, when you did the swap to the super 70 full floater axle, did you confirm that the G80 locker option code is the Gov-lok type locker or clutch style?

Also, did your existing semi floater calipers and driveshaft bolt onto the super 70?

I did more looking this am before church and found cheaper axles somewhat local. However, they were also missing calipers and in some cases, the rotors (which i know don't interchange). When i searched on car part, it never gave the option for a 4.10 except for a cutaway chassis. I assume you prefer the 4.10 over the 3.73s? My research and search continues.

 

[booster]

G80 was that locker and as far as I know it was the only style available.

All the brake stuff is interchangeable. I even had to use my backing plates as the 70s had rusty ones.

The driveshaft is a direct fit, but you are better off to use your axle input yoke and make sure it is indexed the same as it came out (mark it at disassembly) to maintain balance and allow you to replace the pinion seal.

For heavy vehicles like our vans I think the 4.10s are the best choice. Pleasure-way did use 3.73 in their class b Chevy full body van though and we don't hear a lot of complaints about them being undergeared, but there aren't a lot out there either compared to Roadtreks.

Are you sure you were on car-part.com? On the home page you do the search inventory and fill in year, model, state, zip etc and hit search and it should go to another box. Chose the fifth entry "exc. Cutaway; w/o active brake control; 10-1/2" ring gear, 4.10 ratio (opt GT5)"

2005 Chevy Van Express 3500 Axle Assy Rear

​ exc. Cutaway; active brake control (opt JL4) Cutaway, DRW, 10-1/2" ring gear Cutaway, SRW, 10-1/2" ring gear exc. Cutaway; w/o active brake control; 10-1/2" ring gear, 3.73 ratio (opt GT4) exc. Cutaway; w/o active brake control; 10-1/2" ring gear, 4.10 ratio (opt GT5) Cutaway, DRW, 10-3/4" ring gear Cutaway, SRW, 9-3/4" ring gear exc. Cutaway; w/o active brake control; 9-3/4" ring gear, 3.73 ratio (opt GT4) exc. Cutaway; w/o active brake control; 9-3/4" ring gear, 4.10 ratio (opt GT5)

 

[youngnretired]

Thanks for the info and we're actually both correct. I was searching based on a 2007 search and you searched based on a 2005. It shouldn't make a difference for the axle, but it apparently does. The 2005 lists the 4.10 option, the 2007 listing doesn't. It's even more ironic when searching based on a 2009, the options are even different and a 10.5" 4.10 option isn't listed, but a generic 4.10 option is.

 

[booster]

Thanks for the info and we're actually both correct. I was searching based on a 2007 search and you searched based on a 2005. It shouldn't make a difference for the axle, but it apparently does. The 2005 lists the 4.10 option, the 2007 listing doesn't. It's even more ironic when searching based on a 2009, the options are even different and a 10.5" 4.10 option isn't listed, but a generic 4.10 option is.

I think the search cross reference has some missing data. AFAIK, all the 10" Dana 70s axles where the same and interchangeable parts. I put a 2004 into our 2007 van with no issue, and when I looked up parts everything was listed for all. The 70s was used from 2003 to 2009 and after that is was AAR and a six speed transmission.

On your van check the RPO code for ratio to see if the 3.73 is a replacement. GT4 would be 3.73 and GT5 would 4.10 and harder to find which would probably how it got a 3.73 when the stock axle failed, probably just like our 07 did twice. If the RPO says GT5, your speedo would be right for a 4.10 unless whoever changed the axle to 3.73 had the dealer flash the computer to change it.

 

[youngnretired]

I agree and believe that all the super 70 axles (and probably 60's) from 2003-2009 are all the same and interchange.

Ironically I was looking thru my pictures this am to get an idea on brake hose routing and saw the paper tag on the axle in one of the pics. It's 4.10. For some reason I had the idea that it had 3.73 in it, maybe because that's what my truck has in it. The door tag also confirms GT5, but the G80 locker isn't an option on this van.

I sent a request quote to Jellison just this am and expanded my search area further south to try to get out of the rust belt. I would prefer to not have to deal with rust if I don't have to, and this may be a longer search to find one with lower mileage, locker and 4.10 ratio for decent money. I also confirmed with my mechanic about him swapping the axle, inspecting it and the use of a lower mileage axle. Thanks for that original comment on the mileage.

 

[booster]

The G80 was an option on the vans of that era and it was a Govlock. The deal was that the only way to get the Govlock was to buy the 10.5" axle, trans cooler, towing package. AFAIK the Gov lock came in all the towing package vans, but I will have dig out an old brochure to confirm.

 

[youngnretired]

I read that also somewhere else. Ironically, I believe I've found vehicles with the full floater axle, 4.10 ratio and didn't have the external trans cooler or towing package as part of the VIN equipment breakdown. So who really knows, but I've looked at quite a few in the last couple days too.

If anyone needs to know:

Z82 is the towing package
V14 is the auxilliary transmission cooler
VR4 is the weight distributing type hitch
UY7 is the wiring for the trailer