'06 GMC K2500 Buildup


Time for some new shocks!!

Well, several years ago I replaced the Original 150k mile shocks with some Gabriel Ultra's. At the time, I thought it an improvement, especially when the camper was in the back, where the original shocks let both ends of the truck bounce after any sort of decent bump... The Gabriel shocks were definitely better at controlling the truck when loaded!

Unfortunately, I've been living with a pretty miserable unloaded ride ever since, and even with the camper in the back, they're noticeably stiff to the point that I worried it was doing damage to the truck. A recent trip to MI and back without the camper was enough. Time for some decent shocks that aren't so stiff. Having tried both OME and Skyjacker Softride shocks on my Jeep over the last year or so, with only too-stiff results, I decided to give Bilstein shocks a try, and ordered up a set to get them installed before a trip to Prescott to run sweep in the Prescott Rally, where I'd be on horrible roads for hundreds of miles...

I ordered the standard replacement shocks for my truck, which are the same for every '99-'10 2500/3500 GM truck. I did not opt for the "with camper" rear shocks, just the standard units. I it may be a little soft when I have the camper in the truck, but that's ok with me.


Because I run the front of my truck about 1" high, but wanted to maintain droop travel, I stacked about 1/4" of grade 8 washers on the shock before the bushings. It's cheaper than buying new lower shock brackets, and allowed the shock to have the same extended length as the Gabriel units that I took off. The rear shocks were 1/2" shorter extended, and the same compressed length, so I didn't worry about the difference, but that is the only downside to Bilstein's mono-tube design... that for a given extended length, monotube shocks have less travel than a comparable twin tube.

What do I think? Big Fan. The truck rides nice, and the suspension actually works now when going over bumps!! Crazy, I know... :) I had the front (and probably the rear too) off the ground several times over the weekend, and the landings were controlled with very little rebound bounce. I did the opposite going through several washes, and completely bottomed the front, though not harshly. No rebound hop like the OEM shocks had, just controlled return to normal ride height. Washboard was much better, though it's a 3/4 ton truck, so not ideal. Airing down to 40psi helped a lot.

If anyone is wondering if Bilstein's are worth the money, I can tell you without certainty that they are. IMO, there is no such thing as a cheaper alternative... Pay for what you want, have no regrets. I'm going to see what I can work out for my Jeep... The original replacements for it are too short, and the next bump up is for 3-4" of lift, while I have about 1.5" of lift... I wish OME or Skyjacker would pull their heads out of their butts and offer a decent riding shock. Unfortunately, idiots put them on a horribly overweight TJ with the sway bars disconnected and then complain the shocks are too soft... So what I find is that even shocks touted as soft riding are horribly stiff for my fairly light TJ. :(
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So I've had a CVT Rainer roof top tent sitting in the shop for over a year now and we've never used it. The idea is to put in on a rack on the back of the Comanche, but that project is dragging on, and the good tent camping weather is almost gone...

So last week I decided to toss it onto the topper and see what we think of it. We did a weekend trip to Silverton for some exploring and hiking.
I'm still a HUGE fan of the Bilstein shocks, which allowed us to run comfortably up fairly rough roads. More comfortable than my Jeep, that's for sure!!

So here's a few pictures for you!

Saturday morning near Maggie Gulch, north of Silverton:

Looking South toward Silverton:

We drove up toward Buffalo Boy tram house and hiked out to the Old Hundred boarding house. The road up to Buffalo Boy is pretty steep in places, and there are a few switchbacks that took a two or three point turn to get around...

Later Saturday, we headed up toward Animas Forks, and took County 9 in an attempt to get up top and see what once was Lake Emma. We ended up on 99, and then a spur that just kept heading up... This is the end of that spur. From here it's a short hike to a very high overlook. Pretty much awesome.

Since it was getting late, we set up just off 99, across the Animas from Cinnamon Pass Saturday night. Probably about 11,500 feet, since we were right at tree line.

We are loving the RTT!!! In fact, I'm back to working on the Comanche again!! In the meantime, I think the tent is going to live on my truck... It's so handy. (And I don't feel like taking the topper off to load the camper...) :)
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Wow, Chris, that thing looks huge. How big is the platform? I'd love to throw something like that on a trailer. Question- where did the pups sleep?
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This RTT is pretty big... Platform is 72" x 96" - Plenty of room for Steph and I! The dogs sleep in the back seat of the truck, where they also ride. The back seat of this gen crew cab folds nice and flat, making perfect space for dogs. :)

The CVT Rainier also came with an annex room that hangs below the extended side. The Annex would work well for sleeping pups, or kids, or staying out of less than ideal weather. Would probably also allow heating via a Little Buddy style heater. Since we're using the RTT as a fair weather option, I doubt we'll use the annex much... :)


Welcome to Expo Hicks!

I don't live in CO, I only wish I did... I live in Farmington NM. (AKA: Crapholistan)
Not a wonderful town, but great location! We can be in Silverton in about two hours, and Moab in 3-1/2. Lots of other great places in under three hours. Sure be nice to be up in Mancos instead, but wife works here in Farmington for now...


PA Slammer

Any of you guys live near Denver? I'm looking to make the move to the east or south of Denver somewhere.

Love your build BTW. Just started a project of my own. I'll be watching yours for ideas / inspiration!


New member
I'm in Colorado Springs.

Cool build thread, thanks for sharing.

PA Slammer, if you have any questions just let me know. I'm a bit more than an hour south of Denver.


With the wife and I planning a trip to Baja late next month, I've been hammering away at a list of things that have been on my mind... :sombrero:

I firmly believe that real tires make noise, but lately, mine were sounding more and more like a B52 a full power. Usually, that means a wheelbearing is on it's way out... I have been moving a brand new set of complete knuckles around for years, and recently robbed the calipers and brackets off them, so I decided to finish them off and use the wheelbearings so I can scrap the rest.

I couldn't feel any play in the old bearings, but the pass side one sounded perhaps a little dry when I rolled it over. I put the new ones on anyway, after pumping a bunch more grease into them through the ABS sensor hole. (Highly recommend doing this, as there's not much in there!!) I also retained the driver's side bearing as a spare, after pumping it full of grease too. The new bearings should last almost forever, since the originals made 220k miles, seemingly without issue.

Tires have needed a re-balance for a while now, so I decided it was a good time to bust out my tire groover and cut up the huge outer lugs to give them a bit more traction, and possibly less noise. I added alternating large and narrow grooves, hoping that it might reduce the tire noise some too. Front tires were feathered pretty bad, so some grooving should help the wear more evenly too.

(Should have taken a picture when I did it... Not as obvious what I did now that they're dirty...)

They balanced out better than before, and a subsequent trip to Denver revealed that it was the former pass side front tire that was making all the noise. (I moved it to the rear, where I could clearly hear it howling away...) The extra grooving reduced noise a bit right away, and after another 1500 miles or so, they've calmed down quite a bit more.

Finally, with it sitting on stands anyway, it was time to see what was up with the trans... It's been going to limp mode after a cold start, and getting worse for about three years now... Lately, even with temps only around freezing, I was occasionally having issues. I decided to do a fluid change with a pan drop to change the internal filter too, and check out the wiring. Last time I changed the fluid was when I did the trans cooler lines several years ago, and I put two gallons of Transynd in it. I couldn't find any Transynd locally this time, so I bought three gallons of Shell Spirax, which is also TES 295, and at least as expensive as Transynd!!

When I dropped the pan, the pan filter dropped with it...

I took it as a sign that the seal between the filter and valve body was shot, and probably allowing it to suck air when cold started, resulting in the faults I was getting, and subsequent limp mode.

The pan was completely clean, so the spin-on filter seems to be doing it's job. I checked the wiring, which was fine, and put it all back together with new pan and spin-on filters. Topped off with about 2-1/2 gallons of Spirax and it's been totally fine since, with no faulting out down to at least about 15F.
(anybody else notice this little guy is driving a RHD car??)
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Spring Pack Rebuild

Next up, I decided it was time to get rid of the airbags. They work great on the highway, or around town, and OK on mild roads, but the Air Lift 5000 kit I used took the place of the jounce bumpers, so when it does bottom out, it's metal on metal, and pretty harsh! The airbags also have a LOT of rebound if you do compress them going over a bump. They also restrict droop travel quite a bit in my application.

I could spend money on newer bags with built in jounce bumpers, and then add the bases that allow them to lift out, but I don't have much room for the bases without lifting it more, and I'm pretty sure it still wouldn't work as well in the rough as a proper set of springs...

A walk through my favorite local junkyard revealed a nice looking set of 5-leaf springs in a '98 3500 CCLB (Non-dually). I bought them with a plan to "be like Jack" and build a better pack. :)

The '06 springs had four leaves plus a long overload. Even without the airbags, the were OK, but there was some taildragging with the camper in the bed, or with the 5th wheel hooked up. (Camper is ~1600lbs, 5-er about 2500lbs of pin weight...) I figured adding one more leaf would probably work well with the camper in the back, and I don't tow the 5th wheel much, so doing what Jack did and swapping the four bottom leaves and shorter overload from the older pack under my existing main leaf would be a good start! (The bushings use smaller bolts on the older trucks, so you have to keep the later main leaf.)

I disassembled the '98 packs and cleaned up the leaves, painted them with Rustoleum primer and then some Semi-gloss black.

Then I re-stacked them, put the stack under the main leaf, and immediately found a problem. The #2 leaf of the '98 pack was about 1" longer than the #2 of the '06 springs. The new #2 was digging hard into the larger main leaf eyes, and I didn't like that. Cutting it down would have made the plastic sliders too short to do much, so I re-used the original #2 spring instead.

Out with the old...

... and in with the new!

Interestingly, the '98 pack has leaves that are all about 9mm thick, while the two top leaves of the '06 pack were ~11mm, and the two bottom leaves were 9.5mm. In the end, I ended up with a pack that has the top two 11mm leaves from the '06 pack, and the bottom three 9mm leaves from the '98 pack.

The tail now sits about 1.5" higher empty, which looks a little tall, but I don't drive the truck around empty much. If it sits 1.5" higher than before with the camper in the bed, it'll be awesome!! And I put the stock jounce bumpers back on, so I have that going for me too! :wings:

I ordered U-bolts to replace my rusty old ones, and I'll put them on when they come in and call the spring job done for now.
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Currently, I'm in the process of rebuilding the rear brakes. They were working fine, but pads were down to the last 1/8" or so, and I've had pads and rotors sitting on the bench since I did the front brakes this fall. (Factory brakes on both ends could easily have made 250k miles... Wow!)

Well, sometimes things aren't as easy as I imagine them to be... :oops:
I pulled the rotor off the driver's side to find the parking brake completely covered in gunk... (Sorry, no picture.) Looks like the seal had been leaking gear oil, but not bad enough to be visible. One of the shoe linings was missing, and likely had disintegrated into the chunky part of the goop that was covering everything. So I got to rebuild the parking brakes, and replace both seals too.

Though the driver's side was a mess, the pass side was perfect, just a little dirty.

Both parking brake lever actuators were a little rusty, but still free and working fine. I replaced them with new anyway, since the new parts were cheap, and you have to completely disassemble to get to them. Levers and shoes from Rock Auto, since the total through Rock was half what it would have been locally for the same Wagner and Dorman parts!

I always paint the rotors to keep them from rusting. Cheaper than buying the coated ones, and works about as well out here in Wasteland. :)

Got the driver's side back together last night, except for new pads.

Heading out now to get a seal for the pass side so I can finish.

Next up, something fun!! - I need to build a Rear High Capacity Assault Bumper!!
Then two motorcycle carriers; one for the front and one for the back. Going to build a gas can rack into the rear one, so i can carry three 5 gallon cans too, right up against the bumper.
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Expedition Leader
Wow, great update and thanks for the kudos, truck should live another 200k. Hope the springs work as well for you. Of course now you have me wanting to go through mine and make them better.
I love hearing that your brake pads went so long before replacement. Mine still look new all the way around at 143k.