GM fullsize AWD Van Info thread

Scotty D

Active member
Is anyone doing more serious wheeling on an awd chassis with upgraded suspension/drivetrain?

Im looking at building an express out as a semi-fulltime camper and i wanted to go with the awd as I like the 5.3 motor and want something that can do my current offroad trails right out of the box (I have a 4x4 astro currently). my build would bring the van right up against the GVWR of 7300lbs.

It would be cool to swap a 4L80 when the 4L60 dies and put a dana60 under the front someday but Im wondering if the light duty frame just wouldnt hold up to serious trails. not rock crawling, just overlanding stuff you would do with a jeep or toyota (I know thats fairly unspecific, sorry)

Mitch
I dont think you can put in the 4L80 because it messes up the computer.
My van does really well off road in mexico , the biggest problem is its geared way to high
 

Mwood95

New member
I dont think you can put in the 4L80 because it messes up the computer.
My van does really well off road in mexico , the biggest problem is its geared way to high
thanks for the info. what kind of trails are you doing? how much are you lifted?

I have seen quite a few instructionals on swapping a 4L60 vehicle to a 4L80. apparently you need a custom harness and to get the computer reflashed.

Mitch
 

aiguofer

New member
High Output Alternator Help!

My alternator just died on my 2003 Express AWD. It currently has a 145 amp unit, and I'd like to take the opportunity to upgrade to a 250-ish amp unit for charging house batteries and running accessory items. I can't seem to find a section of the thread here with anyone that's done this. Does anyone know of the compatible part code?
Hey, I have the Mechman 250 and it's been working great for me! I'm using a 60A B2B charger to charge my battery bank in the back and everything works smoothly.
 

aiguofer

New member
Thanks! that was super helpful. Here's the info comparing the two shocks for others that might run into this:

Bilstein 5100 (#24-185615): Known to fit
- Extended length: 26.2 in
- Collapsed length: 16.18 in
- Travel: 10.02 in
- Top Mount: T-bar/barpin
- Lower Mount: Eye 0.5559 in

Fox 2.0 (#985-24-005): Does not fit
- Extended length: 26.85 in
- Collapsed length: 16.75 in
- Travel: 10.1 in
- Top Mount: Eye 0.506 in
- Lower Mount: Eye 0.506

So it seems the lower eye is too small in the Fox. This can probably be fixed by removing the tube inside the bushing.
The top mount is different, which can probably be fixed with some aftermarket attachment.
The length difference is probably not enough to matter. I'm rocking the BOR springs which are supposed to be a little taller than stock, so length shouldn't be a problem.

I've reached out to BOR to see what they say. I'm headed that way anyway so I might just end up getting my shocks from them and return the ones I have, or just pay them to modify the ones I have if they're indeed the same part number. Will report back!

Ok, following up on the shock saga. I ended up getting a whole set of shocks from BOR since I was in the area. He installed Bilsteins all around. He installed the 5100 #24-186643 up front, and the 5125 #33-230320 in the back. He suggested the 5125 since they're valved for a bit more weight, and I'm already over GVWR. I returned the Fox 2.0 back to Summit Racing.

Based on what I've seen online, those Bilstein rears only come with eye attachments, so I'm fairly sure BOR converts them to the required T-bar attachment up top. His price was a little higher than ordering them all through Summit Racing or equivalent, but considering the fact he's having to get extra hardware to attach them it's probably a wash. For the fact that he knows his stuff and matches your specific use case with the right shocks it's worth the extra price IMO.

For comparison with my previous post:

Bilstein 5125 (#33-230320):
- Extended length: 24.31 in
- Collapsed length: 15.12 in
- Travel: 9.19 in
- Top Mount: Eye 5/8 in
- Lower Mount: Eye 5/8 in
 

Scotty D

Active member
thanks for the info. what kind of trails are you doing? how much are you lifted?

I have seen quite a few instructionals on swapping a 4L60 vehicle to a 4L80. apparently you need a custom harness and to get the computer reflashed.

Mitch
I am not doing trails per se , I am just trying to get my van to the best campsites. Offroading is not at all my hobby outside of this.
I grew up in a very rural area with lots of barely passable logging roads so my tire placement skills are pretty advanced.
I only have the 2 inch traxda lift and its usually plenty
I also have the g80 locker so even if I only have one or two tires making good contact I can muscle through

These things are amazing in the sand if you air down enough
 

TheEL

Observer
Anyone upgrade from the stock scissor jack? What are you liking? I stripped my scissor jack on my last trip so in the market for an upgrade.
 

whith

Active member
I like bottle jacks. I have a think a 4 ton bottle jack from the local farm and ranch store along with fittings for the top of it from Safe Jack that can cup and hold the frame or axles as well an extension.
 

Parhelion

New member
I had a bay area shop install the Cognito upper control arms, they didn't discuss any challenge; the arms came with instructions. I wanted them to install the Cognito limiting straps, but they didn't figure out a way to drill the shock shroud at the top. They didn't see why they would be needed, but of course they are recommended to limit downward travel and wear. I will tackle the strap attachment soon.
The Cognito control arms have allowed me to crank the front up 3 inches; I can float over bumps and dips with the suspension flexing throughout the full range; the tires are planted, even on the roughest potholed roads. I haven't yet given it a full test offroad , but will report soon. I'll be heading up to the snow this week too.
Hello, i have a 2006 Express that my wife and I converted. I lifted it about two inches with cams, blocks and Rough Country shocks and it has served well. 10 years later the rear springs feel tired but maybe I’m carrying more stuff with a 2 year old along now, at any rate, I’m considering going with the parts you specked out, namely the upper control arms, Billsteins, and suburban springs. How has all this held up for the long term? Would you, have you done anything different since? Thanks!
 
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Boulder Off-Road 2' Pro-Runner Plus Kit en route! Finally, decided to bite the bullet and address the needs for a proper suspension upgrade. I have a few worn and broken parts (Broken leaf spring link, sagging 20yr old shocks, whacked out alignment, oversized BFG KO2's that have never really fit quite right, and a need for my yearly undercoating). It makes sense to get everything repaired, updated, and coated in one go. It's going to be a big bill (the pro-runner plus kit was already $2100 with shipping). I've got a two week window between ski trips, so hoping this will all be wrapped up next week. I'll update the group once it's all in and share feedback from my mechanic's on how it installs and how I feel the driving experience changes after.

A few pictures of how I've been loving the van over the past year. I successfully installed a diesel heater in December before the heart of ski season and I'm loving it!
20230127_145649.jpg20230814_144419.jpg20240113_152530.jpg
 

Willsfree

Active member
Boulder Off-Road 2' Pro-Runner Plus Kit en route! Finally, decided to bite the bullet and address the needs for a proper suspension upgrade. I have a few worn and broken parts (Broken leaf spring link, sagging 20yr old shocks, whacked out alignment, oversized BFG KO2's that have never really fit quite right, and a need for my yearly undercoating). It makes sense to get everything repaired, updated, and coated in one go. It's going to be a big bill (the pro-runner plus kit was already $2100 with shipping). I've got a two week window between ski trips, so hoping this will all be wrapped up next week. I'll update the group once it's all in and share feedback from my mechanic's on how it installs and how I feel the driving experience changes after.

A few pictures of how I've been loving the van over the past year. I successfully installed a diesel heater in December before the heart of ski season and I'm loving it!
Check out my post recommending the Cognito control arms to improve wheel travel range. Looks like a nice project.
 
Check out my post recommending the Cognito control arms to improve wheel travel range. Looks like a nice project.
Yeah. Good call. I've read your post (Read all the 66pgs of post 🤷‍♂️). I'm going to stick with a modest 1.5-2" raise in the front for the time being. With the heavier spring pack in the back, I might have a little stink bug, but I ride heavy in the rear: I'm still adding more cabinetry/bed/flooring, moving the tire to the rear swing out, adding a box to the rear door, will carting around 2 mountain bikes in the spring/summer, and have the two roof boxes laden with gear. I'd like to crank the front all the way up to 3", but your post and others noted the crap ride and additional wear because the angles.

I'll get through the winter and look at another round of upgrades in the late spring/summer. It would be nice to bomb down gravel roads like the Gold Rd in Maine that access a remote fishing spot I like to frequent.
 

Parhelion

New member
Yeah. Good call. I've read your post (Read all the 66pgs of post 🤷‍♂️). I'm going to stick with a modest 1.5-2" raise in the front for the time being. With the heavier spring pack in the back, I might have a little stink bug, but I ride heavy in the rear: I'm still adding more cabinetry/bed/flooring, moving the tire to the rear swing out, adding a box to the rear door, will carting around 2 mountain bikes in the spring/summer, and have the two roof boxes laden with gear. I'd like to crank the front all the way up to 3", but your post and others noted the crap ride and additional wear because the angles.

I'll get through the winter and look at another round of upgrades in the late spring/summer. It would be nice to bomb down gravel roads like the Gold Rd in Maine that access a remote fishing spot I like to frequent.
sounds like
 

Parhelion

New member
Well, I finally got the Cognito control arms installed and the Bill Steen shocks and took it in for an alignment. Everything went well and the ride feels good so far although I haven’t had the chance to really test it out as the vibration that I’ve been feeling was worrisome enough in route to Baja that I turned around shortly after leaving and took it in to GM to find out that my transfer case is going out to the tune of $4300! Unpacked the van into the truck and headed south. I’ve been looking at remanufactured transfer cases from Powertrain Products and they seem like a good option. I would love to put a true four-wheel-drive transfer case in it but I’m not sure how tough of a project that will be and my fridge rides between the seats where I assume I would need to install some sort of pull-chain shifter. If anyone has any experience with installing a new transfer case I’d love to hear it.
 

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