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2006 3500 express SAS with a 05+Ford SD axle

28K views 22 replies 7 participants last post by  macktruck505  
#1 ·
So this is a project I have been working on since December of 2017. If there was one thing i hated about the 155 wb van with the duramax is that it was useless once you left the pavement. I have been stuck on wet grass, a dirt driveway and don't even think of driving it in the winter. Now, I ran my van as a cargo van so it was not loaded with tools, I am sure if I had 1500-2000 pounds of tools it would have been a tank.

My goals for this project are
  1. Make it off pavement capable.
  2. Install 35" tires to give me frame clearance with the LWB.
  3. Maintain the soft coil spring ride quality.
  4. Outfit the interior as a boon docking camper.
  5. Minimize the amount of custom parts for the 4x4. I wanted to be able to buy off the shelf replacement parts as much as possible.

I want to give a shout out to the following builds that i studied/copied. I did not post any links but they are worth finding and reading.
  1. Johny5's Stealth Camper Van on Expedition Portal - SAS van swap.
  2. BigLBZPower08 Duramax SAS with 05+Dana 60 on Pirate 4x4 - Ford axle in a GM truck a lot of small detail information.
  3. Jlane330 build on DP - :thumb:
  4. LCAC_Man build on DP - :thumb:

My plan for this thread is to show another option for a 4x4 van. I will post any part numbers so that the next person does not have to spend hours on the internet looking for just the right part.

To get the ball rolling here is a picture of the van last fall when I parked it in my shop and here is what it looks like today with a little photo shop paint work to get everyone's attention

Mike
 

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#2 ·
I was just reading your post yesterday on pirate, looks great.
 
#3 ·
I purchased a complete 2006 ford F250/F350 front frame clip. This way I received the factory spring mounts and sway bar. I chose to stay with the stock 3:73 gears to match my rear Dana 70. In hind site I should have just purchased both front and rear ford axles. I did not save anytime or money by keeping the 70. I also could have went with 4:30 gears.
When I brought the van inside I put it on oak blocks and spent the time to level it. This made it easy to drop a plumb bob while figuring out the final axle location. I pushed the front axle 2" forward and was able to keep the stock steering box location by using a moog K6653 astro pitman arm. I had to ream the tapered hole and shorten the lower radiator hose to make everything fit. All wearable parts on the front axle are stock ford with the exception of the drag link. I had to shorten and re-thread it. I lowered the spring mounts on the frame to give clearance for heater hoses and allow access for changing glow plugs. This also allowed me to run stock spring and shock length while gaining 6" of suspension lift. This is as high as you can go without installing drop track bar and drag link. I kept the stock ford radius arms by making drop brackets out of 1/4" steel. The only thing I underestimated on this swap is the amount of cutting and grinding required to remove all the factory brackets. :(
I still need to figure out bump stops, but that will have to wait until later in the year.


Mike
 

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#23 ·
I purchased a complete 2006 ford F250/F350 front frame clip. This way I received the factory spring mounts and sway bar. I chose to stay with the stock 3:73 gears to match my rear Dana 70. In hind site I should have just purchased both front and rear ford axles. I did not save anytime or money by keeping the 70. I also could have went with 4:30 gears.
When I brought the van inside I put it on oak blocks and spent the time to level it. This made it easy to drop a plumb bob while figuring out the final axle location. I pushed the front axle 2" forward and was able to keep the stock steering box location by using a moog K6653 astro pitman arm. I had to ream the tapered hole and shorten the lower radiator hose to make everything fit. All wearable parts on the front axle are stock ford with the exception of the drag link. I had to shorten and re-thread it. I lowered the spring mounts on the frame to give clearance for heater hoses and allow access for changing glow plugs. This also allowed me to run stock spring and shock length while gaining 6" of suspension lift. This is as high as you can go without installing drop track bar and drag link. I kept the stock ford radius arms by making drop brackets out of 1/4" steel. The only thing I underestimated on this swap is the amount of cutting and grinding required to remove all the factory brackets. :(
I still need to figure out bump stops, but that will have to wait until later in the year.


Mike
I got the same moog K6653 as you but the 2008 express I am working on has 4 Key and the Moog has 3 keys, what did you do to make this work? Thanks
 
#5 ·
Yes, everything is stock SD ford. The drag link needs to be shorted and rethreaded. I used an Astro pitman arm Moog K6653 with the tapered hole reamed to fit the SD drag link. It is a negative offset.

Mike
 
#6 ·
Since i just showed the front axle it only makes since to move to the rear axle. My plan from the beginning was to add wheel adapters and keep the original Dana 70 with the factory locker and 3:73 gears. I did not notice the 35's with the stock gearing until I hit the highway. It likes to cruise at 80 - 85 mph.
In hind sight I should have swapped in the ford rear axle. I could have went with 4:10 or 4:30 gears. When I was planning the 4x4 swap I never imagined how much time I would spend getting the 70 to work.
I needed six inches of lift to match the front. I started with a shackle flip and then added a two inch lift blocks. The shackle flip moved the axle ahead so I had to make up a offset center bolt to get the wheel centered in the wheel well. Next I cut the spring perchs off of the axle to get the pinion angle correct. Then it was the brake lines. Vans use a rubber hose at each wheel instead of a single hose drop like a pick up. To correct this I converted my axle to a truck style brake line system and used a pickup braided steel hose kit. I think LCAC_man did a better job on his rear brake lines. I thought I was done with modifications until I went to mount the shocks. The RS9000 shocks have a large tube and yes ,they hit the axle tube. I had to cut and move the shock mounts. Since I ended up cutting and moving all the mounts it would have been just as easy to slide a ford axle in instead of the 70.
I was also able to dump the exhaust out the rear by cutting the pipe at the elbow flipping it and welding it back on so he elbow becomes the down spout. It will work until I can pick up an aftermarket exhaust.
I think my next post will be on the ABS and brake system.

Here is a another photo shop picture for all to enjoy.

Mike
 

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#7 · (Edited)
My ruffstuff perches came with 3 spring pin center holes, I've just got mine in the center one now and had planned to wait until I drop the body on it to see where it landed in the wheel well...maybe I'll just shift it back now. I've got a couple different lengths of shackles to work with so that will help tune the rear height.
cutting those old spring mounts off and installing the new couldn't have been any fun with the body still on!
For anyone starting fresh that doesn't already have parts to work with, being patient and finding a set of 05 up SD axles that are optioned with 4.30 gears is definitely the way to go...if I were starting fresh today that's what I'd do and just do the modification to the speed sensors to get the ABS to function. It's a lot cheaper to pay a couple hundred more up front and not have to regear (if you're going to run 34-35" tires).
 
#8 ·
You may want to push the axle back now. I had to move mine 1.5" back to get it close to the center. I am still ahead a little but it is not bad. My total wheel base now is approximately 156.5". The following picture shows how far the axle swung forward. The blue tape has a black original center line and the silver shows how far it moved.
I don't have a shop lift but I was smart enough to put the van up on 24" oak blocks. This made it easier to sit under the van while cutting and grinding.
 

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#10 ·
The ABS system turned out to be very simple. The first thing I tried was making an adapter to plug the ford sensors into the GM system. I thought it would work since there is a vendor out there that sells them for $140. This solution did not work, when I did searched the forums I found someone that bought them and found them useless. The easiest solution is to remove the ford front wheel sensors and install the factory GM ones. One of the pictures shows the ford and GM sensors side by side. Yes, it is that simple. The right side cable fits and plugs in at the stock location. The left side is short by a few inches. I chose to make a short extension cable so i did not have to modify the sensor or the stock harness. The rear is handle by the the speed sensors in the transmission, which you don't have to touch.

For the front brakes the factory GM fittings are m12 fittings on 1/4" lines. The ford brake lines are 3/8 on 3/16" lines. Since I wanted to stick with an off the shelf ford 4" over stainless brake line. I converted the m12 to 7/16 then used a 7/16-3/8 adapter. I looked everywhere for a simple m12 - 3/8 adapter and never found one.

Mike
 

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#12 ·
For my transfer case I was planning on using a ford 205. I had stock piled a married and a divorced units, I was not sure exactly which one I was installing. In the end I decided against using either of them.

I installed a NP261 since i had a clean low mileage unit. A 241 would be much cheaper since you need a flange front output. The 261 does not have one so I installed a SYE kit from Northwest Fabricators and a pump rub kit.

For the install you need to cut the trans output, shorten the transfer input and plug the oil feed for the original tale shaft bushing.

In the end I was glad I went with the 261. I think I installed it at least five times. Trying to lift the cast iron 205 would have about killed me. Yes, my trans lift is by ARM STRONG. The 4l80 - 261 was a stock combination so i can get replacement parts anywhere. You can get a brand new 4L80 - 261 adapter from Amazon for $65. I had checked on ebay and they want $100 for used ones.

I did take Len's advice and just fabricated a new cross member.:thumb: This saved so much time versus modifying the original

For the transfer case shifter i copied Johny5's design. The chrome lever is a pin from cheap horse shoe game.
 

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#13 ·
What did you do with the motor mount area? I am in the middle of this conversion myself and am trying to decide what I want to do with that area after I cut the crossmember out and opened up the bottom of it.

I have a 6.0 so it might be a little different but probably not too different.
 
#14 ·
What you do with the motor mount (particularly the drivers side) is lift dependent. If you are lifting 7" or more then you don't need to do much other than just trimming off the attachments for the crossmember/control arms. If you want to go lower you might have to consider a custom mount for the drivers side. There really isn't anything needed for the passenger side.
 
#16 ·
Like LCAC said, it all depends how much lift you will have. I cycled my suspension before installing the springs and just kept trimming until I felt comfortable with how much clearance I had. I did infill all the factory holes in mounts.

Mike
 
#20 ·
Mummn I’ve seen some photos of ones that looked pretty good. Looking to get unlocking front hubs, and cheap axles to do conversion at home. Looking to do newer 3500 extended 2.8 d max with 08-10 super duty axles 3:55 or 3:73 factory electric locker in 10.5. Planning 285/17’s only. Looking to run 271 transfer case.
Thanks,
Deo


Sent from my iPhone using Tapatalk
 
#21 · (Edited)
I've never seen a solid axle conversion on a van anywhere near that small amount of lift and I can tell you I've put a lot of hours into looking at every thread I could find on it...again...not saying it can't be done...but you'd be in for a lot of fab work to get any kind of compression travel and not bottom out on the motor mounts/oil pan.
The overall flatness of the front frame section is really a limiting factor.
 
#22 ·
I a pretty sure this was the picture showing the suspension fully compressed with a 35" tire and axle two inches forward. The axle tube is almost touching the frame. You can get any lift height you want. it just depends how much modifications you want to do.

Mike
 

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