2008 GMC Envoy Denali

[n8in8or]

He looks frosted over, almost about what I look like after being on the deer stand in frigid temps for several hours.....

Heck the car wash out the road shuts down when its 20 some degrees or less, you can't stand up in there when it gets so cold. I think they are afraid of liabilities also.

Nice work Nate, keep the pictures coming.

I was kind of surprised to see them open, but very happy that they were.

 

[n8in8or]

Not a ton of progress today since I couldn’t go any further until the UPS guy brought me my Smart Shell.

I got the Smart Shell installed per Sonnax’s instructions.



Then I moved on to the Input Clutch Housing Assembly. Lots of fun bits in here. Unfortunately I ran into a snag after 5:00.....the clearance for the forward clutches is too large, so I need to get a thicker backing plate.

To see if I would need another 3-4 backing plate or not I installed that too. This is an upgraded 8 clutch set instead of the factory 6 clutch set. Dana from Pro Built was nice enough to write the clearances right on the backing plate. Luckily I was in spec for this set.



So now I just need to find the other backing plate tomorrow morning so i can keep moving forward.

 

[n8in8or]

Yesterday was a bit of an experience. First I had to go to the transmission shop to get the clearance issue on the drive clutch figured out. Then when I got to the reverse input clutch I ran into a clearance issue again....so back to the transmission shop. When I moved on to the oil pump I opened up the shift kit and found way more springs than I expected, and they looked like the springs that were in the spring cages I had already installed! So I called Dana at Pro Built Automatics and he said, “didn’t you see the instructions?”, uh no.....what instructions? “They’re in with the separator plate”. Oh. I hadn’t opened that because what was visible just looked like valve body instructions, but in there he had also put other assembly instructions....including some that would have saved me one of the trips to the trans shop, and of course instructions on replacing the springs in the spring cages. So now I had to disassemble the forward drum again so I could put the new springs in the spring cages in there. In the end though it all worked out and I got all of the internals done in the trans.



Today will be valve body and accumulators. I should be able to get it finished today I’m hoping.

 

[BIGR]

Very nice indeed, I admire you for taking on such a project as the transmission, it would scare me to start working on one of those with my limited mechanical ability.

Good luck and keep us updated on the progress. We all want to see that project completed, hear you fire up the engine and maybe do a test drive.....

 

[n8in8or]

Very nice indeed, I admire you for taking on such a project as the transmission, it would scare me to start working on one of those with my limited mechanical ability.

Good luck and keep us updated on the progress. We all want to see that project completed, hear you fire up the engine and maybe do a test drive.....

Thanks. Auto transmissions have always scared me, but I just decided it was time to not be scared and do it. I definitely see why we pay people to rebuild transmissions, but in the end, it’s just another mechanical system.

Oh yes....there will be video.....

 

[smokymtn65]

@n8in8or Great job! Back in the late 90s I had a 81 c-10 SB w a 402 I built in it, I blew the Turbo 400 out the was in it. So I thought what the heck I can do that so I rebuilt it and it working good, for a while there is a little bolt the goes in the middle I left out, anyway over a few thousand miles and spinning tires when it hit second almost every time, it finally exploded. So off to local trans shop here, the guy that owns it is super! I asked him to tell me what I did wrong and he told me. A few months later he let me did through his junk pile for transfer case parts for the 6.2 K-10 I had when I got it fixed . He stopped me and offered me a job! lol

 

[DieselSlug]

Definitely a task there. Something I just have never felt comfortable tackling myself. Mainly due to the large labor burden if you did mess something up and have to take the trans back out. I am all in for ripping engines apart haha but the trans just turns me off.

Kudos to you for taking it on!

 

[n8in8or]

Update: I got it all bolted together yesterday.



This has been an interesting experience. I know I saved money so I like that aspect for sure. I also got a first hand accounting of what’s in the transmission. I would definitely do it again, but I don’t think I’d tackle every transmission....like if the trans in my girlfriend’s Impala went out would I commit to rebuild that one? Not sure on that. Part of what made this project manageable was the Transmission Bench videos. So if I tried to do one with just manuals how would that go? As far as buying the kit from Pro Built Automatics, I know I paid extra for that kit, but what I got for the extra money was a kit of parts selected for my application and how I drive. It was a mix of Transtec, Sonnax and Trans-Go parts with modified instructions just for my build. He even had some parts labelled with Sharpie pen to guide installation and the Trans Go separator plate was pre-drilled for me. I am still disappointed he didn’t have me buy the Sonnax Smart Shell upgrade, but he must be one of the guys that thinks the updated GM drum is fine. I’d rather be safe than sorry. So I think until I was more confortable on what parts to buy I’d probably do another kit like this. So a good and rewarding experience, but I’m happy it’s done. On to the engine now.

 

[BIGR]

Good deal @n8in8or. What does that transmission weigh? I recall years ago when I was a teenager we took a turbo 350 out of a car and had to get it rebuilt. I was alone one day no help, I picked it up and loaded it in the back of a Chevy C-10 pick up, hauled to the transmission guy. It didn't seem too heavy, heck maybe it was 130 pounds or less, just kind of awkward getting hold of it.

 

[n8in8or]

Good deal @n8in8or. What does that transmission weigh? I recall years ago when I was a teenager we took a turbo 350 out of a car and had to get it rebuilt. I was alone one day no help, I picked it up and loaded it in the back of a Chevy C-10 pick up, hauled to the transmission guy. It didn't seem too heavy, heck maybe it was 130 pounds or less, just kind of awkward getting hold of it.

I’m not sure what it weighs. Probably just a bit more than a TH350 since that’s kind of what it’s based on.

 

[n8in8or]

This week I picked up the balanced rotating assembly from the machine shop. So cool having all those shiny bits home.

Then Tuesday I got the cam and torque converter ordered. I had been struggling with what cam to choose. Then it dawned on me that I should ask the guy doing the tune what cam and converter he would recommend. He actually went wilder than the other recommendations I received, but he was the only person I talked to face-to-face about it and that was really reassuring. He said it would do everything I wanted so I pulled the trigger. He spec’d a custom grind Ultradyne cam with 222/230 duration and .601/.601 lift and 114 +4 LSA. Definitely wilder than I was planning, but I’m not upset about the idea....it should be really healthy sounding and a lot of fun to drive!!

For the converter he spec’d a Circle D converter with 3000-3200 stall. Again, higher than I planned, but with everything working together it should be stout and fun.

Unfortunately the cam had a lead time of 3 weeks, but it is what it is. I wish I had thought to ask the tuner earlier and gotten this process started sooner. BTW, the tuner is Tyler at Force Engineering - this is the same place where I ran the Tahoe on the dyno. He has a really good reputation locally and I like him personally to boot.

So that’s the latest on the parts front. I also ordered some other small parts, but nothing too exciting.

I’ve been working on the heads, but that’s for another post....I’m not quite ready to share the status on those.

While I had my grinding station set up I decided to port the throttle body. This is supposed to be 5-ish free horsepower. Here’s before:



And here’s after:



Then I cleaned the workbench off so I could switch over to engine work. I cc’d the dish in the piston and the combustion chamber so I could calculate my compression ratio - I’ll need to figure out how much I need the machine shop to shave off the deck of the heads to reach my target ratio. Then I moved on to installing the crank in the block.



This is the nicest looking crank I’ve ever owned. It’s a brand new Chevrolet Performance LS2 crank. Then I got the ARP studs installed and checked my main bearing clearances. The clearances were good so I final installed the crank.



After that I installed one rod and piston so I could measure the piston to deck relationship (also part of the compression ratio calculation). The piston is .004” above the deck after milling the deck of the block.

I also stripped off the paint the machine shop put on the block. I found out later it wasn't very good paint - it would wipe off with brake parts cleaner. I should have just had them leave the paint off. Tomorrow I’ll put KBS Motor Coater paint on it.

 

[n8in8or]

Yesterday was mostly cleaning and painting. I painted KBS Motor Coater aluminum paint on the block with a brush.



Then after degreasing the other parts I sprayed them with Motor Coater aerosol.



I also calculated my compression ratio. With an .051 thick gasket I’m at 9.9:1 after opening the combustion chambers up to 68cc. My tuner said that will work fine for 87 octane gas, which makes me happy.

 

[THEFERMANATOR]

With as big a cam as you're running, I would bump it up. Don't worry so much about your static c/r so much as your dynamic c/r. And by bumping it up, you could get an e-85 tune to really make some power.

 

[n8in8or]

With as big a cam as you're running, I would bump it up. Don't worry so much about your static c/r so much as your dynamic c/r. And by bumping it up, you could get an e-85 tune to really make some power.

Oh yeah, big power is tempting, but I want to be able to run 87 octane since it's going to be my daily and I'd like to use it on trips, too. What static compression ratio would you say is the max for 87 octane?

 

[FellowTraveler]

Update: I got it all bolted together yesterday.

View attachment 56209

This has been an interesting experience. I know I saved money so I like that aspect for sure. I also got a first hand accounting of what’s in the transmission. I would definitely do it again, but I don’t think I’d tackle every transmission....like if the trans in my girlfriend’s Impala went out would I commit to rebuild that one? Not sure on that. Part of what made this project manageable was the Transmission Bench videos. So if I tried to do one with just manuals how would that go? As far as buying the kit from Pro Built Automatics, I know I paid extra for that kit, but what I got for the extra money was a kit of parts selected for my application and how I drive. It was a mix of Transtec, Sonnax and Trans-Go parts with modified instructions just for my build. He even had some parts labelled with Sharpie pen to guide installation and the Trans Go separator plate was pre-drilled for me. I am still disappointed he didn’t have me buy the Sonnax Smart Shell upgrade, but he must be one of the guys that thinks the updated GM drum is fine. I’d rather be safe than sorry. So I think until I was more confortable on what parts to buy I’d probably do another kit like this. So a good and rewarding experience, but I’m happy it’s done. On to the engine now.

Great job there.....Nate I'm sure it will become second nature to you as you do more.

Perhaps the easiest transmission build for me was the 47RH however; it was on a fresh rebuild that had about 3.5k miles on it so I did not have to guess what was wrong.....my build was to enhance it and use the best of everything I could find saving BIG BUCKS.

 

[n8in8or]

Great job there.....Nate I'm sure it will become second nature to you as you do more.

Perhaps the easiest transmission build for me was the 47RH however; it was on a fresh rebuild that had about 3.5k miles on it so I did not have to guess what was wrong.....my build was to enhance it and use the best of everything I could find saving BIG BUCKS.

Thanks FT! This 4L60 also didn't have any problems (according to the PO) and I didn't find anything unusual when I had it open so it was fairly easy. I can definitely see it getting much easier to tackle as you do more of them.

 

[n8in8or]

I contacted my tuner and he thought I could run up to 10.5ish on 87 octane with my combo. I ran a few different scenarios and if I run a .040 thick gasket and have .013 milled off the heads that will get me 10.41:1 compression. I'll need to check piston-to-valve clearance and push rod length, but hopefully both will be ok since I'll only be .024 less than stock.

 

[THEFERMANATOR]

Oh yeah, big power is tempting, but I want to be able to run 87 octane since it's going to be my daily and I'd like to use it on trips, too. What static compression ratio would you say is the max for 87 octane?

Most I know Normally shoot for 9.5-10:1, but they all run at least 92 octane, and that's dynamic. I've read others running as high as 11:1 on pump gas with the LS platform, just make sure your combustion chambers are clean with no burrs as the slightest edge can give you detonation. I would say a dynamic c/r of 9:1 should be safe for 87/89 octane, and you will have knock sensors to help. That big cam is going to knock your dynamic down quite a bit from your static.

 

[n8in8or]

I understand the concept of dynamic compression ratio, but I’ve never tried to calculate it. This is a other reason I’m pleased with my decision to have the tuner spec the cam - it was nice to be able to get his opinion on the CR since he knew what the cam was and how he plans to tune it.

I knocked all the edges off the chambers.

 

[n8in8or]

Finally got the heads ready for the machine shop. The intake bowl is a bit unconventional - I researched what people are doing with the swirl ramp that’s factory in the heads. Most people grind it out, but I was inspired by work that Tony Mamo of AFR is doing and by the GM LS7 heads. Tony said he uses a feature like that to “direct the pressure” where he wants it. That made a lot of sense to me: the air is going to struggle more to get past the shrouding, so why not force it past and try to get more even distribution? However today I was second-guessing myself, so I talked to Dave at Irwin Racing Engines (the shop that is doing all of my machine work) about the heads when I dropped them off for milling and a valve job. First, he was impressed with the quality of the work I did, so that felt good. Regarding the swirl ramp, he said he had no idea what it would do without putting it on a flow bench. He said it could do something really cool or it could be a dud - no way to know without trying it, but he was impressed with what I was able to execute. The flow bench he works with is about an hour away, which of course would delay the project further.....really not necessary for a build of this level, just more of a curiosity. He didn’t see anything that scared him so he didn’t think it was worth changing them. So I’m leaving the heads as-is and as a result I’ll have a bit of a rolling science experiment. On to short block assembly now!