GM fullsize AWD Van Info thread

[stevets]

It is most likely fluid coming out of the vent tube. This could be caused by several things. Most likely things are overfilled fluid or clogged cooler. Fluid probably got a little hot on the climb and vented out. It doesn't take much hitting the exhaust to make a lot of smoke. Also, check transfer case fluid level since the vent tubes are teed together. Fluid can leak from the trans to the transfer case causing transfer case to be overfilled.

This is exactly the kind of actionable advice I was looking for. Many thanks.

 

[stevets]

sackettmw nailed it! Thanks alot!! The transfer case WAS overfilled by maybe 2 cups - enough to make a difference there but an almost insignificant amount in the tranny.

At any rate, I've drained the excess from the TC and topped up the trans and all seems to be good.

Unless someone is sneaking in and adding fluid to my trans, I've got a new cooler in my future.... unless there is a way to "unclog" these?

 

[PURPLE HAZE]

sackettmw nailed it! Thanks alot!! The transfer case WAS overfilled by maybe 2 cups - enough to make a difference there but an almost insignificant amount in the tranny.

At any rate, I've drained the excess from the TC and topped up the trans and all seems to be good.

Unless someone is sneaking in and adding fluid to my trans, I've got a new cooler in my future.... unless there is a way to "unclog" these?

While test driving my 2012 the same issue occurred. We took it to a shop and the first thing the mechanic did was pull the fill plug on the transfer. Fluid spewed out and he replaced the plug. Told me the seal between the transmission and transfer weeps on several AWD Chevrolet models. Told me to check it once in while to prevent it. A hot day and a long hill at highway speed will tell me I forgot to check it. A friend has a 2004 that does it as well. The vent tube dumps it right on top of the exhaust.

 

[jmvar]

While test driving my 2012 the same issue occurred. We took it to a shop and the first thing the mechanic did was pull the fill plug on the transfer. Fluid spewed out and he replaced the plug. Told me the seal between the transmission and transfer weeps on several AWD Chevrolet models. Told me to check it once in while to prevent it. A hot day and a long hill at highway speed will tell me I forgot to check it. A friend has a 2004 that does it as well. The vent tube dumps it right on top of the exhaust.

Remember that these transfer cases need to be overfilled. There is a TSB: 08-04-21-004 that describes the procedure. You fill it up to the fill port, then close the fill port. Pull the speed sensor and add an additional liter of fluid. A forum member posted info in post #205 of this thread.

 

[Fc3434]

I’ve seen on this thread many have put on the Hellwig 7623 rear sway bar, this fits the 1500 van. Mine is lifted 2”, would the 7635 bar for the 2500 fit on a 1500? I’m guessing yes.

 

[TeleSteve]

I’ve seen on this thread many have put on the Hellwig 7623 rear sway bar, this fits the 1500 van. Mine is lifted 2”, would the 7635 bar for the 2500 fit on a 1500? I’m guessing yes.

As best I could gather when I did mine, the 7623 (1-1/8") and 7635 are the same shape bar but with different mounts and the 7635 is 1-3/8". It didn't look like the 2500 mounts would work with the 1500 rear axle. I never had the 7635 in my hands though. The 7635 works with a 2" rear lift.

 

[pwilk]

I wanted to post some info regarding stubborn torsion key removal.

As somewhat expected the keys were rusted to the torsion bars on my 2014. I tried all the typical tricks:

1. Liberal soaking with penetrant, both homemade and from the store (applied for many, many days)
2. A bit of heat, as much as I thought I could do without altering the temper on the bars
3. Pneumatic hammer
4. Regular hammer, as big a one as I could swing while under the van

None of these tricks worked at all, not even a little. After a month of putting it off I decided to give it another go yesterday and came up with something I think worked well and might help someone else. I removed the tranny crossmember and removed the torsion bars, keys, and their mounting channel from the vehicle entirely. I didn't take any photos as I was trying to beat the worst heat and sun in my driveway. From memory this is what I did:

1. Lift the front end of the vehicle and support with jack stands.
2. Use a jack to support the transmission just forward of the crossmember.
   1. I supported it as close to the tranny crossmember as I could, but leaving space to eventually remove the crossmember. I put a 2"x8" between the jack and tranny to spread the weight better against it as that section looks to be a fluid pan. There's no need to apply much pressure at this point. The jack will just keep the tranny in place when you remove the crossmember.
3. Remove the crossmember.
   1. This was remarkably easy in my case. First, remove the non-structural bolts—holding brackets. On the driver's side there's a brake line bracket into the frame rail, remove the bolt. Just a little closer to center there's another bracket (fuel line I think?) held to the crossmember with two bolts, remove those. Now for the structural bolts. There are three bolts into the frame rails on each side. Lastly there are two bolts in the center into the tranny. The crossmember was lighter than I expected, but don't drop it on yourself.
4. With the crossmember removed there will be no obstructions to removing both torsion bars, keys, and crossbar all from the vehicle.
5. Remove the crossbar that the torsion keys mount into.
   1. There are two large (22mm socket) bolts on each side. Again don't drop this on your head, it will be heavier than the tranny crossmember because the bars are heavy.
6. At this point you should be able to lower the torsion key crossbar and the torsions bars. You'll have to pull the bars rearward to clear them from the control arm. If the front of the bar is stuck, you should have sufficient space to pop it with a hammer and unseat them. The hex on the control arm is far more generous and so they shouldn't be stuck much if at all.
7. Remove the whole thing from under the van and go to your workbench.
8. At this point you've got whatever space you need to wail on the bars with the keys clamped in a vise. On one side I needed many hits with a 4lb hammer to finally get the key and bar separated. Consider working the bar back and forth to get it out so give it a few raps in the opposite direction and then back the way you want. Penetrant probably helps.
9. Reverse the moves to put it back together. However, put each torsion bar and key in while under the van after you've installed the key crossbar. Don't forget lots of anti-seize just in case you've got to do this again!

One other point, if you do any amount of DIY work, especially for a big vehicle, get a second smaller jack. I having two or more jacks is so nice while your working alone or just making the job of positioning things easier. I was able to install the rear Suburban springs solo by using a jack to support the bulk of the weight of the springs. Much easier than trying to manhandle those things.

Hope this helps someone out there.

 

[mobydick 11]

Hi folks, I have been looking for an AWD van for a bit now. I have found three to choose from .I would like your thoughts if you have the time . First van is a 2004 with 180,000 miles , says it needs engine and body work $3,000. Second is a 2012 with 62,000 miles $16,500. Third is 2013 120.000 miles 15,000. This van was government owned and is in very nice shape with highway miles. I know the last two seem like high prices, but vans in general are bringing higher prices in my area . What's your pick ? or keep looking ?

 

[86scotty]

My pick would be the second without knowing anything more about them. I'd skip the first for sure if anything else is available. The price of the third with double the miles of the second makes the second seem much less desirable but we don't know a lot here. Color, options, location, etc. How does all that work out for you?

 

[mobydick 11]

My pick would be the second without knowing anything more about them. I'd skip the first for sure if anything else is available. The price of the third with double the miles of the second makes the second seem much less desirable but we don't know a lot here. Color, options, location, etc. How does all that work out for you?

I would agree . I always try and get the newest year and lowest mileage for my buck when buying used . I can not tell you much on the second van yet .as the dealer listed it but has not received it on his lot as of yet. Buy the way I also found a 2018 3500 Quigley van 24,000 miles for $33,000. Not sure if that would work for me as a daily driver .

 

[Willsfree]

I'd jump on the 2012 if it is mechanically sound. Seems like a great deal to me. Probably won't last 20 minutes...bring your cash.

 

[86scotty]

Agreed. TIS not the time to mull over a van purchase for long or it will slip away.

 

[mobydick 11]

Agreed. TIS not the time to mull over a van purchase for long or it will slip away.

Well I keep checking and its not on the lot yet. So unless I want to put a down payment site unseen I must be patient . After my last purchase a Doka Syncro from an auction unseen because of Covid , I am paying the price big time for this mistake . I am reluctant to blindly jump in . It is blue that's all the new info I can get .

 

[86scotty]

I’m with you, I wouldn’t buy or deposit unseen with a dealer. I would bug them though.

 

[mazzstar26]

Does anyone have a mechanic near Denver that they trust to work on their AWD mods? I trust my local guy to do my basic maintenance and engine work but I think custom suspension mods is out of their wheelhouse for sure. Boulder Off Road does good work from what I have seen and their labor prices are reasonable but what is the extent of their knowledge? I'm looking to replace my UCA's with the Cognito's and limit straps, and wondering who would be up to the task of installing the straps with the fab work required.