GM fullsize AWD Van Info thread

[peterbozeman]

These vans sit about 1-2" higher in the back from the factory.

Having the back be higher so that fully loaded it would be level. Why would people not want to keep that?

 

[peterbozeman]

Ok, here is what I discovered about buying torsion keys on Amazon; torsion keys are not created equal.
Here is a quick little comparison between some keys. Here are the contenders:

1. KSP $37 https://smile.amazon.com/gp/product/B06VWN1QLS/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
2. MotoFab $40 https://smile.amazon.com/gp/product/B01N4LOPMF/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1
3. Shankly $25 https://smile.amazon.com/gp/product/B07T86FGRQ/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

Here are some pictures of them sitting on my stock keys (2007 Chevy Express AWD).
The torsion bar engagement hex of the aftermarket key is aligned with the hex of the stock key, and the two stock keys are parallel.
Therefore, the aftermarket key that is pointed "lower" should create more lift.

MotoFab on the left. KSP on the right.



MotoFab on the left. Shankly on the right.



Shankly on the left. KSP on the right.



I tried the KSP first and got 1.25" lift over stock (adjustment bolt in same position for both).
I tried the Shankly next and got 3.25" lift over stock (adjustment bolt in same position for both).

 

[TeleSteve]

Having the back be higher so that fully loaded it would be level. Why would people not want to keep that?

With my van fully loaded at or a touch above GVWR. It sits perfectly level with 1" more lift in front . With the lift and before my buildout it still sat higher in the back. I did 3" front and 2" rear suspension lift.

 

[peterbozeman]

With my van fully loaded at or a touch above GVWR. It sits perfectly level with 1" more lift in front . With the lift and before my buildout it still sat higher in the back. I did 3" front and 2" rear suspension lift.

Cool. How do you measure level? On the bottom of the frame?

 

[Teacher88]

The amount that the bolt is turned to has no effect on anything other then lift. Some people think that 2" of lift from a key that is only cranked down half way is better than 2" of lift from a key that is cranked down all the way. They think it gives a better ride. This is false.

The more u turn the torsion BAR the higher the suspension goes. Simple as that. Doesn't matter how you turn it. What does matter is the geometry of your front end parts after u crank your torsion keys. Balljoints, cv joints, uca hitting droop stops, not having long enough shocks. These are the things that will effect ride or parts wearing prematurely.

Why does the rear of my van sit higher? Same reasons everyone stated but also because I wanted brand new leaf springs and no lift blocks. I went with the 2500 surburan springs and ended up with this amount of lift and am happy with it.

To measure lift or "being level" park your van on flat level ground and measure from ground to top of wheel wells. Make sure u do this to driver and passenger sides in the front to make sure they are the same. Sometimes you may have to crank a key more on one side then the other to get same amount of lift although I dont think this is very common

I spent so much time researching lifting the front of these vans and torsion bar suspension before I did mine so if you need any help let me know

Sent from my SM-G960U using Tapatalk

 

[MoonMan]

I tried the KSP first and got 1.25" lift over stock (adjustment bolt in same position for both).
I tried the Shankly next and got 3.25" lift over stock (adjustment bolt in same position for both).

How the ride with 3.25" lift? I got 1.75" with the F150 keys, but was afraid to crank down too much. It rides nice where it is at. Just wondering if you've noticed anything negative cranked down that much. Thanks.

 

[simple]

Adding to what was said here. Cranking arms down reduces the available downward travel which helps keep wheels in contact with the ground when going over bumps. If the arms are set to ride at the bottom of their travel to gain up travel and ground clearance there is a handling trade off which must be paid. A practical example would be taking a corner on a fire road with washboard conditions. If the dampening and travel is not tuned right the wheels will be in contact with the ground less of the time and the vehicle will more easily brake traction and be harder to get back under control.

 

[goin camping]

Tranmission question.

Is the Chevy 4l75e a direct bolt in replacement for the 4l60e?"

 

[North]

Some good input here on the torsion bar lifts. If I'm understanding correctly, creating more lift by rotating or increasing preload on the torsion bar comes at the expense of reducing down travel, regardless of the method used to add more preload to the bar.

- I'm assuming lifting without losing down travel requires more complex/expensive parts (new spindles, control arms, etc)?

Haven't lifted my van yet and this will all make more sense once I do, just trying to understand the basics more completely.

 

[peterbozeman]

How the ride with 3.25" lift? I got 1.75" with the F150 keys, but was afraid to crank down too much. It rides nice where it is at. Just wondering if you've noticed anything negative cranked down that much. Thanks.

With the 1.25" I felt no difference from stock handling in my 2007 AWD.
With the 3.25" it felt a little squirrelly and tippy compared to stock. Not dangerous, but not as tight.
I backed the adjustment bolts out until I had 2" of lift. I put 2" lift blocks in the back. That feels like a good compromise. It is a little different from stock, but not substantially.
I would recommend the Shankly. They are the cheapest and give me the most range. I can probably adjust the bolt to .5" above stock to 4" above stock with them.
I could have bottomed out the KSP keys and only gotten about 2.25" of lift. I want to keep the option of 3" of lift in my back pocket in case I want to bump up to that.

 

[Natrone]

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?



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................

@86cj - I am also trying to decipher the GT4 (3.73) vs. possible GT5 (4.10) dilemma for my 2003 2500 AWD....see attached picture of axle sticker:

 

[marret]

Interesting axle tag. I have the G80 axle, but mine is "LOC" for the diff for auto locking and under ratio, it has 4.10. Based on the GT4 RPO code you appear to have the 3.73.

 

[TeleSteve]

Interesting axle tag. I have the G80 axle, but mine is "LOC" for the diff for auto locking and under ratio, it has 4.10. Based on the GT4 RPO code you appear to have the 3.73.

I think the the 4111 on the axle tag is the tooth count on the ring and pinion 41/11= ~3.73.

 

[Scotty D]

Why doesnt my van have an axle tag like that?


2009 awd 1500

 

[crenninger]

Proud new owner of a 2006 1500AWD Passenger with a partially started conversion.
Van has 2 issues which I am hoping to gather wisdom from here

1- typical white paint peeling on the hood and top of the side doors. What are the option?
-- Professional painting, sounds expensive.
-- spray can primer/paint -- sounds doable but I'm afraid of heavy spots.
-- Vinyl wrap -- unsure on cost.

2- Only mechanical issue is a seeping front differential pinion seal.
-- I am mechanically included but never did this repair. Is there any DYI documentation somewhere?

Any advise, experiences shared would be great.
Thank you!