2008 GMC Envoy Denali

[n8in8or]

I didn’t get it done today like I hoped to. For some reason I was just moving slow today and taking longer on everything than I normally would have. And then when I got to the brakes I found that the pads were more worn than I expected so I decided to order new brakes and put it together with brand new parts rather than do old parts that would need to be swapped again very soon. So at this point what I have left is the ABS sensors, all of the rear brakes (including parking brakes which I’ve never done so I don’t know what to expect with those) and reinstalling the rear fascia. I’ll also probably have to play with the air suspension ride height sensors too. I won’t have all of the brake parts until Tuesday so I’m hoping to have it all buttoned up Tuesday night. Then Wednesday I’ll take it to the tuner to have the tune adjusted for the 4.10 gears. The Spohn control arms & panhard bar, the Bell Tech shocks and the JDM sway bar sure are pretty.

 

[n8in8or]

Crap. I let this thread fall behind and now I have a lot of catching up to do. Here goes....

To finish off the rear I made some more changes. A while back the factory compressor crapped out. It would still run, but the solenoids wouldn't open to allow air into the bags. At that point I still wanted to keep the air ride suspension for a couple reasons: 1. I had already invested in new air bags. 2. I liked the idea of having the rear ride height adjust automatically (especially since I am planning on towing our trailer with it). 3. I just like things to be the way they are intended to be. So I did some research and it looked like a lot of peoples' problems stem from buying reman'd compressors - the thing that went wrong originally with the compressor is fixed, but then the next thing goes wrong. A new GM compressor was stupid expensive, but there was a place in Germany selling brand new compressors on eBay....and since the original compressor was made in Germany, this seemed like a good option. If the original lasted 11 years, I was happy with the idea of another 11 years. So I bought that. And it worked great.

Fast forward to the rear suspension rehab and when I plugged the compressor back in, it wouldn't turn on. So to get it back on the road I rigged up the air fill that I had previously rigged the first time the compressor failed. A couple days later I tried plugging the original compressor in and it turned on....ok, so the new compressor failed. I plugged the new one in and it turned on too! Weird. Ok. So I start hooking it up.....and it stopped working again, plus the fittings were stripping out. Ok, I'm done with the air suspension. I should have just done what everyone else does and put springs in it. I guess that's why everyone else does it. So I got the Bell Tech lowering springs and a pair of Air Lift bags so I can add some extra load carrying capacity to the rear as necessary. I put the fill valves in the cubby for the air system so they would be out of the way but readily accessible. I want to rig up a working compressor so I have on-board air to fill the bags, but for now I'll just use outside air.



When I originally installed the springs it sat about an inch lower than it should have for some reason. It was also lower than I wanted it. So I bought some 1" spacers also from Bell Tech and installed those under the springs. I don't have pics of those installed, but here is the stance I ended up with.



Right now, the front end is 1/4" higher than the rear. That will be addressed.....

 

[n8in8or]

Next thing I needed to do was start playing with the tuning to get ready for towing. I mostly wanted to play with trans stuff, but I'm also interested in playing with the engine tune. My tuner uses HP Tuners and said he didn't lock the tune so I could play with it if I wanted. So I bought HP Tuners to do some messing around. So far I've only played with the torque converter lockup a little. There's more I want to do, but I haven't had time to play much. I did do one data logging run and it's really interesting the data you can see! More to come on this I'm sure.



And after the data logging I saw some things I wanted to keep track of real-time...…plus I wanted to monitor transmission temperature. An nGauge would be perfect, but the $400 price tag isn't. What I did instead was get a used Google Nexus 5 for $50. I downloaded the Torque Pro app that lets you configure the gauges you want to monitor. Then I got a windshield mount and wire in a USB power supply in the dash. Now I have multiple gauges I can monitor, plus do 0-60 and 1/4 mile stuff if I want. It's a pretty neat tool to have at my disposal. More of this to come as well....

 

[n8in8or]

Last post before lunch is over....

Time to upgrade the front to match the back. The main driver for this was doing the diff swap so I would have 4.10 gears front and rear. You have to tear a significant amount of the front apart to get the diff out, so I figured that it made sense to upgrade the front suspension at the same time. This project would also contain the typical de-rusting and rust preventive painting as the other areas have had. I took Friday and Monday off of work with the plan being: Friday - teardown/wire wheel/paint prep, Saturday - paint, Sunday - assemble.

Here's what Friday looked like at about 2:00 in the afternoon. Yes, you have to remove the oil pan to get the diff out. Ugh.

 

[n8in8or]

I'm going to sneak one more post in. This is where the weekend fell off the rails..... I went to put the diff I purchased with 4.10 gears in and...………………...the bolt holes didn't line up. Dammit!!



I knew there was an interchange to be aware of, but I misunderstood what was being described. Once I had them side by side, I saw what they were talking about. In the pictures below, I am pointing to the holes that are missing in early differentials.



So I did some searching and decided my best course of action was to take the 4.10 gears out of the one diff and install them in my original 3.42 diff. I ordered a rebuild kit from Summit and hoped it would show up in time to keep me on schedule. Then I disassembled both diffs.

 

[n8in8or]

So I regrouped..... Friday after I ordered the rebuild kit I wire wheeled the frame and the suspension parts I was reusing (the knuckles, sway bar bushing brackets and the strut links).

Saturday was paint prep day. I applied the KBS Klean degreaser and then the KBS Rust Blast.

Sunday was paint day. I painted the new AC Delco lower control arms, the reused suspension parts and the frame.



I didn't receive the rebuild kit Saturday. Fed Ex was showing a delivery date of Tuesday. So rather than waste a vacation day I went back to work Monday and took Tuesday off instead. The kit actually showed up Monday afternoon so Tuesday after work are started assembling the diff to get a jump on Tuesday. I honed out the existing pinion bearings to make getting the pinion shim selection easier. I was pleased to get it set up right the first try! These 7.2 IFS axles are strange since you don't have a cover to work through, but they are nice that there are adjusters on both sides of the carrier rather than shims. I used my GM manual to set it up, but I also found a nice thread on setting a 7.2 up that was a nice supplement to the factory manual.

offroadTB.com • View topic - How To: Setting up 7.2" IFS Diff Gears

 

[n8in8or]

Tuesday morning started with final assembly of the diff. I had it ready to install by 9:30.



After that it was diff installation time and suspension assembly. It took longer to assemble everything than I thought it should, but I got it all together and back on the ground before dinner. I assembled the suspension with Prothane polyurethane bushings in the lower control arms, DJM upper control arms with poly bushings, Moog problem solver outer tie rod ends, Moog polyurethane sway bar bushings, Prothane sway bar end links and Bell Tech struts with the existing springs and new Moog strut mounts.



The struts have selectable collars on them for setting the ride height. I installed a collar set that would drop the front .5", which should have been perfect based on where it was sitting before (the cast iron 6.0 already dropped the front a bit, but it needed just a little bit more...). And the stance was pretty much right where I wanted it. The front measures 31-5/8" at the wheel well and the rear measures 31-7/8" at the wheel well, so 1/4" rake. I wouldn't mind if the front settles just a touch more, but at least I don't have a Carolina squat!



Another thing I was pleased to see was how the DJM arms kicked the top of the front wheels out flush with the wheel wells.



I think I need to get some spacers for the rear now to get them flush with the body.

 

[n8in8or]

When I started the truck I had a check engine light. I ran the codes and it said there was a fault with the cam position sensor. Hmmm. Maybe I accidentally disconnected it when I was rooting around in there? I rolled under the truck and found that I had pinched the cam sensor harness between the block and oil pan. Dammit! So Wednesday night I worked on that. I hadn't gotten the harness between the pan and the gasket, but it was crushed in the gap between the pan and the block that the thick LS gasket makes. I was able to pry it out and I found one of the 3 wires had the conductor exposed and some of the strands were broken. I cut the bad section out and soldered in a new piece of wire. That took care of the code. Then I installed the inner fenders that I hadn't gotten to Tuesday night.

The last thing I did Wednesday was paint the new driver side valve cover..... I have still been having some oil consumption issues and at least some of it has been getting sucked into the intake via the PCV system. I have read about some LS engines having this problem due to the design of the valve cover. GM designed a new valve cover in 2010 I think it was, so by changing the valve cover you can fix the problem in a lot of cases. I bought the redesigned valve cover (PN 12570427) and put some of my leftover engine paint on it after cleaning it.

Here are some comparison pics. It isn't drastically different, but hopefully these small changes do the trick.



Thursday night I installed the new valve cover and then trailered it to the shop my brother works at to get it aligned. I'm excited to pick it up tonight and do some driving this weekend! I don't think this is the end of the suspension work though...… The rear Bell Tech shocks are stiffer than I like, so I'm going to be replacing those with something adjustable sooner rather than later. I suspect the struts are going to be the same way, but I'll find out when I start driving it. If so, then I'll have to replace those with more expensive adjustable, coil-over struts, but since it's my daily driver that I also plan on taking road trips with, I want the ride to be nice, so the investment will be worth it. But for now it will work. Next up: towing our camper the weekend of September 20th.

 

[FellowTraveler]

You never cease to amaze me with your skill-set and drive.......EXCELLENT!

 

[ak diesel driver]

X2

 

[n8in8or]

You never cease to amaze me with your skill-set and drive.......EXCELLENT!

X2

Thanks guys. I think it's the forum that does it. I feel like once it's out there on TTS I need to make good on moving a project forward.

 

[Husker6.5]

Now, about that skid steer, Nate. . .

 

[n8in8or]

Now, about that skid steer, Nate. . .

SAVAGE!!

 

[Husker6.5]

SAVAGE!!

Don't ya know it!

 

[Husker6.5]

You need to clone about three more of you to take care of all those projects!

 

[razur65]

n8in8or Thank you for posting the projects and work you do, gives me direction and confidence for some of the work I want to take on!
I am planning to rebuild the front differential in my 97 'Burb, looking at your posts and information you put up about it makes it easier to say "yup, I can get that done".

 

[n8in8or]

n8in8or Thank you for posting the projects and work you do, gives me direction and confidence for some of the work I want to take on!
I am planning to rebuild the front differential in my 97 'Burb, looking at your posts and information you put up about it makes it easier to say "yup, I can get that done".

Cool! With the right resources and tools we can do just about anything. It’s also nice posting on TTS because collectively there is a lot of experience here and if one of us gets in a jam there’s a good chance someone knows how to get you through. Good luck with the front diff!

 

[n8in8or]

Drove it a couple hundred miles yesterday. I definitely need to change the shocks. These shocks are way too stiff for our Michigan roads. On a positive note it handles the curves awesome now! But if I have to give up a little cornering to gain some ride quality I’m fine with that.

Today were some little things. First I reinstalled the washer reservoir. When I was putting the truck back together earlier this week I cracked the reservoir at one of my seams while trying to put it back in place, so I re-welded it and clearanced the inner fender more so it wouldn’t hit like that again. While it was up in the air (I had to remove the filter from the bottom) I did some looking around. I noticed some oil on the oil pan and diff. Weird. It looked like it might be coming from a plug on the left front of the block. So I wiped everything down and started the engine up to see if it would drip. Sure enough, after just a couple minutes I could see a drip running down the block. So there’s some of my oil problem too!



The plugs were installed at the machine shop so I wasn’t familiar with how it was installed. According to the manual there is supposed to be a sealing washer on it, but when I removed it there was nothing. Then I remembered the 5.3 block so I removed that plug and there was no washer there either, but it did have pipe dope on it. So I applied the GM thread sealant on it and reinstalled it. Hopefully that’s the last of my oil loss problems.

Next I started working on stuff to get it ready for camper hauling. First I installed the trailer brake controller. This is the first vehicle I’ve had that already has the wires run for a controller....the 7 pin plug is even factory installed. Nice. That makes it so much easier.




Then I set the height on the hitch. Surprisingly it only needed to be one hole higher than the Tahoe.



Just about time to hook it to the trailer and see how it does.

 

[DieselSlug]

SAVAGE!!

Since we are on the band wagon I am waiting for the I6 Ford haha.

 

[DieselSlug]

Drove it a couple hundred miles yesterday. I definitely need to change the shocks. These shocks are way too stiff for our Michigan roads. On a positive note it handles the curves awesome now! But if I have to give up a little cornering to gain some ride quality I’m fine with that.

Today were some little things. First I reinstalled the washer reservoir. When I was putting the truck back together earlier this week I cracked the reservoir at one of my seams while trying to put it back in place, so I re-welded it and clearanced the inner fender more so it wouldn’t hit like that again. While it was up in the air (I had to remove the filter from the bottom) I did some looking around. I noticed some oil on the oil pan and diff. Weird. It looked like it might be coming from a plug on the left front of the block. So I wiped everything down and started the engine up to see if it would drip. Sure enough, after just a couple minutes I could see a drip running down the block. So there’s some of my oil problem too!

View attachment 57974

The plugs were installed at the machine shop so I wasn’t familiar with how it was installed. According to the manual there is supposed to be a sealing washer on it, but when I removed it there was nothing. Then I remembered the 5.3 block so I removed that plug and there was no washer there either, but it did have pipe dope on it. So I applied the GM thread sealant on it and reinstalled it. Hopefully that’s the last of my oil loss problems.

Next I started working on stuff to get it ready for camper hauling. First I installed the trailer brake controller. This is the first vehicle I’ve had that already has the wires run for a controller....the 7 pin plug is even factory installed. Nice. That makes it so much easier.

View attachment 57977View attachment 57975
View attachment 57978

Then I set the height on the hitch. Surprisingly it only needed to be one hole higher than the Tahoe.

View attachment 57976

Just about time to hook it to the trailer and see how it does.

Grab yourself a little bit of the black wire loom, did this when I installed a aftermarket controller on my father-in-law's F150 and it looks much sleeker than the rainbow of wires. Another trick I have done was drill a small hole in the kick panel, put in a rubber grommet and run the wires directly in hidden by the case of the controller. Of course I can't find pics of either of these (stupid photo bucket issues).

Cant wait to see this thing in action!