GM fullsize AWD Van Info thread

[zuren]

Hey, i know the AWD Express/Savana came with the 3.42/3.73 Front gear ratio. My rear end has a factory sticker on it, that says it's ratio is 4.11. I have the 03 Savana AWD. Is it possible for me to have a 4.11 rear end with the front gear ratio being so much different? I haven't looked at the parts sticker to see the code, but i'm assuming the axle is original. But from what i understand about gear ratios matching, this can't truly be possible. Or can it? The AWD works great, had a big snow storm here not too long ago, and the van drove just as good as a 4X4.

My parents have a Roadtrek 210 Popular (2WD) on the Chevy 3500 van chassis and if I remember correctly, the RPO codes said it had a 4.11 rear end. It is entirely possible that your has 4.11 gears.

It has always been my understanding that the gears in the front end need to match the rear. Otherwise, as mentioned, the drivetrain would grenade. Everything needs to spin at near the same RPMs.

 

[Accrete]

Howdy, y'all! Long time lurker here. I'm running an 04 Savana 1500 AWD that I started building out one year ago.
...I'm not doing things completely budget, but I'm not looking to spend 2500 on just a rear bumper with a galley box...

Greetings and welcome to the forums. And enjoy the build/adventure in your rig.

Just as an FYI for any who might be "looking" for the rear bumper/galley box combo... we totally enjoy having them on our AWD van, even little hops to the dunes or a nearby river it is a quick swing and set for the camp/picnic galley.

Thom

 

[Accrete]

Installing the BOR rear suspension kit in our rig

Cari has been wanting to beef up the rear suspension for a couple years now so i went ahead and ordered the Boulder Off Road kit for the Van.
Below is a picture of the parts received in the kit.
We are having our professional mechanic friend do the install next week (same one who installed the BOR Lift a couple years ago).

I will report back the results : )
Thom

 

[Pest]

That's just the rear sway bar kit, yes?

 

[Accrete]

That's just the rear sway bar kit, yes?

Correct.
We already have the BOR AWD lift installed (+ ~2.75") and went up to 265/70/r17 tires.

 

[Pest]

Correct.
We already have the BOR AWD lift installed (+ ~2.75") and went up to 265/70/r17 tires.

Thanks. I thought so, but wasn't sure. I'm curious how the ride feel will change with that. Do report back!

 

[wjeeper]

Curious how bad the body roll you have currently. I have seen a few Express guys adding rear sway-bars. I went the other direction...........I tossed my front sway bar a few months ago and haven't regretted it for even a second! The front suspension acts more independently than it did with the bar in place offroad its a night and day difference. On the pavement it feels basically stock, the wife couldn't even tell a difference.

 

[Twobilly]

Hi all,
Bump stop / Jounce question. New poster here so sorry if this belongs somewhere else - just let me know. I have a 2013 AWD Savana that I lifted 2" key lift (front) and 2" block lift (rear). Not completely satisfied with ride quality. My front and rear bump stop/jounce bumpers have not been adjusted down to match approximate distances as on the stock suspension (i.e. my suspension ranges up farther before it contacts the bump stop/jounce bumpers). For example, my front lower control arm (LCA) bump stop rides approximately 3/4" off the LCA. I think the factory setting is closer to 1/4". On the back, my bump stop/jounce bumper is riding at least 2" higher off the mating surface on the axle than factory. While new to GM vehicles I believe this all negatively affects ride quality per what I understand from this site: http://www.gmfullsize.com/tech/torsion401.html

Anyone know of any replacement parts or shims or something to get these important suspension parts closer to their factory clearances?

 

[wjeeper]

Why limit the your suspension travel? As long at the tires don't contact the bodywork, the springs don't compress into the negative and your not bottoming out your shocks travel is travel.:sombrero: I know Chevy designed their IFS suspension to ride on the bumpstops, but its a piss poor design in my opinion. Bumpstops are a super important part of a suspensions design but they shouldn't be relied on as an active part of the suspension. A good set of shocks valved properly will provide a progressively valved ride without resorting to smashing bumpstops. My van sits farther off the bumpstops and it doesn't feel any different than stock with some decent shocks.

 

[86cj]

Hey, i know the AWD Express/Savana came with the 3.42/3.73 Front gear ratio. My rear end has a factory sticker on it, that says it's ratio is 4.11. I have the 03 Savana AWD. Is it possible for me to have a 4.11 rear end with the front gear ratio being so much different? I haven't looked at the parts sticker to see the code, but i'm assuming the axle is original. But from what i understand about gear ratios matching, this can't truly be possible. Or can it? The AWD works great, had a big snow storm here not too long ago, and the van drove just as good as a 4X4.

The RPO code for a 4:10 axle is GT-5, GT-4 is 3:73 and GU-6 is 3:42.. I would like to see a pic of the tag on the axle, I am a little skeptical as GM is very consistent to a fault most of the time....the 4:10 was listed for a 2500 van but possibly not an AWD 5.3 2500?

Hi all,
Bump stop / Jounce question. New poster here so sorry if this belongs somewhere else - just let me know. I have a 2013 AWD Savana that I lifted 2" key lift (front) and 2" block lift (rear). Not completely satisfied with ride quality. My front and rear bump stop/jounce bumpers have not been adjusted down to match approximate distances as on the stock suspension (i.e. my suspension ranges up farther before it contacts the bump stop/jounce bumpers). For example, my front lower control arm (LCA) bump stop rides approximately 3/4" off the LCA. I think the factory setting is closer to 1/4". On the back, my bump stop/jounce bumper is riding at least 2" higher off the mating surface on the axle than factory. While new to GM vehicles I believe this all negatively affects ride quality per what I understand from this site: http://www.gmfullsize.com/tech/torsion401.html

Anyone know of any replacement parts or shims or something to get these important suspension parts closer to their factory clearances?

If you are running your stock shocks they are topping out now and making the van feel harsh in the front, and if you have longer front shocks you are hitting the droop stop with the upper control arm and making the van feel harsh, this happens close to 3", at about 2-2 1/2" it is less harsh. That is really the only issue that could be better, getting some more travel up front helped a lot on big bumps and made me think torsion bars aint' all bad.

Most lifts with bigger tires use lower bumpstops to keep the tires off the fenders and keep the longer shocks from compressing closed, it is proper but so far nobody here has lowered them. Our vans fit the 265-70-17's at stock height so tire rubbing is a non issue and the shocks we run are not much longer under compression, "don't use 2" front shock spacers they will compress your shocks" tried it. Timbren makes some bigger bumpstops they ad spring rate for carrying a plow, I have not seen or used them but have thought about it. Trailready used to make some 1" longer polyurethane ones for a Hummer H-3 that might work in the front, I put some Z-71 factory bumpstops in the front of my van they are a little better. I added a rear sway bar because it did seem like it leaned over onto the front bumpstop when the wind had a strong quick gusts, not a big deal but the rear sway bar stopped it. It used to do the same thing when stock and empty, it would lean over on the rear bumpstop in the same wind conditions, when loaded even a little the rear bumpstop would touch the lower pad and firm the handling right up. Most stock 1500 vans have soft rear springs and almost no rear up travel because they ride on the big bumpstop alot, that is why no sway bar was needed, mine handled good with a little load but big bumps were harsh. The 2" lower rear bumpstop pad will give your rear springs more abuse flexing further, you dont have a thick bottom leaf to fight back. I suspect that is also what you don't like the feel of, the 2900lb rear springs some of us use ride great and the bottom leaf should stop to much compression, and cure any wheel hop................

 

[Twobilly]

That's quite helpful. Thanks. My van is loaded quite heavy most of the summer. I raised the van 3 years ago. For background the front end on mine has MaxxCam keys and Bilstein 5100 series 24-186643 shocks which I gather from other posts should be pretty good. Was hoping a lower bump stop might help a bit on the occasional big bumps. Seems the long travel and rebound can be pretty strong on those as it is right now. Im not aware of any other shocks that might fit our raised vans and have stronger damping. I feel the front is acceptable right now as is, but I'm limited by my own knowledge on this stuff, which is what makes this forum so helpful.

The rear end is where I suspect I have bigger problems right now. I have stock springs, a 2" block, Roadmaster active suspension (for towing and some additional load support). I screwed up and ordered the Bilstein 5100 series 24-187237 shocks with the wrong upper mount. I had to modify the upper mount to the T-bar mount for fitment. The spring setup really isn't quite up to the task for my uses, but the shocks seem under damped to me. Body roll is too much for my liking (have considered adding rear sway bar) and the shocks can't rein in the bouncy feeling on big bumps. Occasionally I get a strong back and forth rocking action when making sharp turns. I was thinking lowered bump stops might stop some of this, but maybe the right action is different shocks and rear sway bar.

My plan is to go to the 3/4 ton rear springs (22-907) with Bilstein 4600 series 24-221948 shocks and see how that works before adding rear sway bar. I need the load support and stiffer shocks make sense. Any feedback appreciated!

 

[rbressler]

Has anyone managed to mouse proof their gm van?

We live in the country and they'll get into the cabin and find any food or paper product. I think they coming in through the cabin air intake so I'm planning on adding a hardware cloth screen somewhere in there. I'm also wondering if there is a spot where a cabin air filter could be retrofitted as with the similar erra gm trucks.

It looks like there is also a cabin air pressure vent in the right quarter panel (part number 15025607) which may need to be screened. Ours is a passenger van and i'm not sure if there is another pressure vent hiding somewhere behind the trim. Anyone know?

 

[era]

Add a Leaf instead of 3/4 ton springs

I just bought a 2012 awd and will be doing a build out plus towing a 3000# boat in the summer and snowmobiles in the winter...I know that I will need to beef up the rear end. Just wondering why it appears no one has gone with the full length add a leaf option instead of buying a full new spring pack? https://www.generalspringkc.com/Add_a_Leaf_G1500_Chevy_Express_GMC_Savannah_1996_2012_s/2085.htm

 

[86cj]

Why springs?

Add a leafs work OK when the load is constant but can be rough to live with when lighter, they also don't always fit well with the pack and work smoothly. The best reason is that the we know the 2900lb spring pack works very well on our Vans, they give almost 2" of lift just from the packs thickness alone and the bottom leaf helps with wheelhop. They are actually a great deal at $150, plus the fact that it can be easier to install the spring packs than Add a leafs kind of seals the deal.


BTW I have air bags on every vehicle except my AWD Van, I did not like the way they mounted, not much room right there. That pushed me into looking at springs and it was the wheel hop issues that swayed me, soft springs on blocks don't interest me. Your factory rear lower bumpstop cup helps with wheel hop because they almost touch at ride height, so when the pinion climbs they touch, you loose that when you add a lift.

 

[era]

Makes sense...I also run airbags on my Tacoma and really like them but it doesn't look like there is a kit for 2012 van? The one firestone kit I could find stops at 2009. Does anyone know what the change was or if that kit will fit? http://www.sdtrucksprings.com/index...ucts_id=4449&gclid=COHspraBkdMCFYZafgodjYwDmA

If it won't the 3/4 ton springs are probably the ticket. I'm not too worried about lift just want the added payload without sag.