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2004 chevy trailblazer_ls
8 Posts
Discussion Starter · #1 · (Edited)
So to start off, this is my second time typing this post. I had it all done, and then I hit submit and I had been timed out and logged out, and lost all of my work. So now I am typing it in Word, first. I hope I do as good of a job the second time. I will say it's definitely lighter on words this time, but I think the message still gets through. And now I'm finding out my post is to big, I can't post images, on and on go the error messages....

I had a user name here before, but it was a few years ago and I forgot what it was and had to make a new one.

Back in November, my Dad noticed a growling coming from his 2003 Trailblazer in the front. It sounded a lot like wheel bearings, so he got two new hubs. When I jack up the truck to changed the hubs for him, I found that the frame where the control arm mounts, and essentially completely rusted away on the driver side. I'm kind of surprised there wasn't a bad accident, actually.

So I set about finding another TB, and found one that was also a 2003, the body and interior were shot, but the frame was in great shape and the rear axle was a limited slip diff (Bonus!), so we picked it up, and the project began. None of this would have been possible without the help and support of my Dad (granted, he just wants his TB back) and my best bud Zach.
Ignore the other random junk:

I had originally intended to just do a quick body swap on a friend's 2-post lift, I figured 2 or 3 days worth of work. Well, his shop got busy and I wasn't able to use that. So my Dad and I designed a lift with lumber and chain hoists:

Here's a weight test, the entire donor TB supported with one set of hoists and one 10k pound ratcheting strap... Like a champ!!:

I had intended to use the hoists and straps to do all of the lifting of the body. Unfortunately, there was no good way to lift at the front, and in the rear the strap crushed the quarter panels:

So for the front I was able to hook the hoists directly to the framework of the body, in a slot behind the front fender:

It bore the weight nicely, and allowed for a full lift off of the body:

Then I rolled the frame out of the way, and developed some caddies to carry the body and allow me to safely roll it out side. This is version 2 of the rear, the braces running forward to the second body mount location were added after the first one failed going over a bump. Luckily that was not on the good body, to no harm done.:

In the front, I was able to get away without braces, the steel around the body mount location was wide enough to fully support the 2x6 against flexing. Even so I saw it moving some later, if I did this again I would use braces on the front as well:

Now that I could safely set down and move the body, I wanted to develop a damage-free way to lift the rear of the body. I tried a few things, but decided the easiest way would be to laminate four 2x4's into a beam, and place a 2x6 on top as a spacer, and bolt it to the body mounts inside the wheel-wells. This worked well, and with a few minutes with jack stands and jacks, is not that hard to place or remove when the chassis is underneath. Also, all of these wooden fixtures are bolted into the body mounts to secure them:

The swivel casters on all corners made it very maneuverable, but three people would be the minimum if your area wasn't completely flat- it still weighs a lot!:

Then I moved the good frame out as well, and rolled the black TB in for dis-assembly:

Growing parts pile in yard:

Learning with the other body means it was a snap to make up some more caddies and put them on:

More to come in a moment....

2004 chevy trailblazer_ls
8 Posts
Discussion Starter · #2 · (Edited)
First post, continued.....

Then I rolled the black body outside to join it's cousin:

I had to remove the good drivetrain from the black TB frame before I put it out in the “asture” as well:

Good motor coming out:

Once I had that frame rolled out, I brought the good chassis back in:

Then it was time to remove the drivetrain I wasn't going to use. Dad snapped this before I could scurry out of the shot....:

Look, twins! And floor space becoming a premium commodity. Note that I used a board and straps to lift the radiator stack out at the same time. I wanted to reduce the number of things I disconnected as much as possible:

At that point, we made the decision that it “doesn't cost much more to go first class”, and I removed some more things, spent a day with a wire wheel taking off loose rust.....:

And chained the frame up to my pickup:

And dragged it down to the spray-n-wash! The donor TB had a lot of grime and grease on the front of the frame, so I blasted it all off:


Before pressure wash:

After pressure wash:

Then we got it back to the garage and strung up again:

I don't have any pictures of what I did next, but I used a rust converter solution on the whole frame, followed by a topcoat of Rustoleum Semi-gloss black:

While we had it all torn apart, we decided it was also a good time to replace any worn suspension items:

More to come in a moment...........

2004 chevy trailblazer_ls
8 Posts
Discussion Starter · #3 ·
Then it was time to mount up the good drivetrain. I revised my lifting rig so that it all sat level:

Drivetrain in, halfshafts in, brakes on:

Then I hoisted it up high, and drained all the fluids out. She got brand new fluids everywhere:

Then I rolled the completed chassis out, and got the good body brought back in:

Reassembly went pretty quickly at that point, basically just lowering it down a little at a time and keeping everything lined up:

And it's down:

At that point it's all pretty standard stuff, putting the fenders back on, the front and rear facia's, hooking stuff back up under the hood.

In summary:
Black TB parts used:
All body parts, all body wiring and modules, Drivetrain, driveshaft and anything electrical mounted to it, radiator stack and hoses, brake calipers, rotors, and hoses.

Scrap TB parts used:
Frame rails, chassis wiring harness (The Transfer case connector location was different, but the wire colors seemed to match up and the connector reach, so I went with it. I wish now I had used the other chassis harness), ABS module, fuel tank and pump, rear axle, steering rack

New: Alternator, Serpentine belt, Power Steering Pressure line, front and rear sway bar links, front and rear sway bar bushings, front wheel hubs, outer tie rod ends, upper control arms, upper and lower ball joints, front strut assemblies, fuel filter.

Now, on to the issue I'm having. When I took the truck for it's alignment and AC recharge, about 90% of the drive time, the gauges for fuel, coolant temp and oil pressure would fall down to the pegs, the battery light comes on, and the check gauges light comes on. The underline on the PRND321 display also goes out. No drivability problems, nothing acts funny except the gauges. It seems to be random, not triggered by any event. Right before it happens, the voltage gauge drops down to around 12 volts, like the alt shut off or died. Then every now and then, they will start working again.

Once I got to the shop (about a 30 minute drive), they had to jump it to move it. So they checked out the battery and alt. Battery was good (after being recharged) and the alt was putting out about 13.3 volts, a little lower than I would like, but acceptable. However with the truck running it was still pulling 20 amps from the battery charger, so I replaced the alt and belt when I got home. The gauge problem is still there. Now I am suspecting the alt wasn't bad, it maybe was not getting it's turn-on signal from the PCM.

I jacked up the rear of the truck and ran through all the gears, even loading up the trans with the brakes, and I can't get the gauges to fail. But as soon as it hits second gear out of my driveway, 9 times out of 10, they act up. Sometimes it seems like coming to a hard stop makes them work again. Some times not all of them come back. But WITHOUT FAIL, if you stop and put the truck in Park, they go right back to normal. It's got me confused.

I took apart and re-connected all the connections I made under the hood, no changes. It either has to be related to the motion of the car, or the rotation of the front wheels. No ABS light like it was caused by the wheel hubs or leaking A/C current. The alternator is brand new now. My next option is to swap the chassis harness, and that will be such a pain in the butt since it's all put back together.


2004 chevy trailblazer_ls_ext
1 Posts
awesome job

really great write up ,getting ready to do the same ,except i have a 04 ext v8 tb only donor with a decent frame i found was a 06 ext lt wich means i have to swap everithing incl .axles and fuel system ,motor mounts ,and all the wiring ,wish me luck , fyi my frame actually broke at the left rear trailing arms top and bottom
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