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2006 chevy trailblazer_lt
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7 Posts
Discussion Starter #1
Well my 4.2 liter inline 6 threw a rod this morning and i lucked out finding a 2004 5.3 liter for 400$ with PCM and complete harness, so now its time to start the swap, I've already got a pretty good idea of everything I may need
Only deal is the 5.3 came out of a pick up so I have to check my oil pan clearances, and im probably gonna just splice in the 4.2 BCM and Fuse panel into to 5.3 wiring harness I know it takes a little more time and its a hell of a lot more than anyone really wants to do but at the same time I'd rather do this than spend 600-1200$ on a complete wiring harness, and seeing as how i can't find a whole lot on anyone going thru with the swap because somehow they feel its not at all feasible, well I guess its about time to show you that if you want it you can do it
 

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2002 olds bravada
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13 Posts
Where have you ended up on this so far? I take if yours is a 2wd? If not, I'm sure you have figured out the TB oil pan has the differential attached to it. Also, I6 frame has the crossmember in a different location than a V8 one.
 

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2006 chevy trailblazer_lt
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7 Posts
Discussion Starter #3
Where have you ended up on this so far? I take if yours is a 2wd? If not, I'm sure you have figured out the TB oil pan has the differential attached to it. Also, I6 frame has the crossmember in a different location than a V8 one.
Well I have only gotten as far as pulling motor and trans and getting lm7 ready I had quite the parts list to search for and I'm still looking for a set of motor mounts but everything is looking good I'm going to 3in exhaust with electronic cutout and getting a tune to delete some o2 sensors and the get valve as well as the smog equipment. Pretty much looking at doing a ss power train swap once I get it all done. But for now I'm just gonna use the 4l60e that it came with. Yeah it's only a 2wd I went ahead and got the oil pan tho got headers y pipe all the belt driven accessories I'll get some pics posted soon. But come to find out it threw a rod and I had all the pieces in my oil pan it was pretty wicked.
 

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2004 chevy trailblazer_ls_ext
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48 Posts
The new motor had a thrown rod? Or the 4.2? Only reason I'm confused is because you've already stated that the 4.2 threw a rod in the first post.
If it's the new motor then that's a bummer.
 

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2002 olds bravada
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Doing similar right now but I'm doing a complete TBSS AWD frame swap on my wife's Bravada. Will take measurements on the frames to finally have a definitive answer as to what exactly is different. Pretty sure all that is different is the trans crossmember location; engine mount bracket holes appear to be in the same spot and same configuration...
 

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2006 chevy trailblazer_lt
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7 Posts
Discussion Starter #6
Im coming along hust trying to find the full motormounts with brackets not having much luck.

Tried uploading photos of old block damage and new block but not having much luck on my phone hope to get them up soon tho.

RYANA. keep me posted on your swap I would like to see hiw it comes along and itd be nice to know the exact differences on the crossmemeber or whatever else
 

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2002 chevy trailblazer_ls
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99% complete 02 trailblazer ls with lq4 6.0 here. The crossmember will have to be modified , as the trans will be a few inches further foreward. The engine mounts I have were purchased from Nalley Brunswick GMC in Brunswick Georgia. The oil pan and oil pump pickup tube was purchased through eBay, as it is necessary if you have and want to keep 4x4. The driveshafts were ebay used units as well (just replaced u-joints) from any v8 trailblazer based (swb) truck, al la envoy denali, bravada, rainier, 97x 5.3, etc. Exhaust came from OBX, which fit beautifully. I also installed an ls hotcam kit, double roller timing chain, and high volume oil pump. The only warning I can give to anyone doing this swap is remember to use the correct o-ring for the oil pump pick up, as they are not the same.
Also, I have only 1 issue, and it's the ebcm/bpmv mounting on the driver's side frame rail. After the swap, with the headers installed, the driver's side exhaust practically rests on the abs pump/module. I have yet to see any photos as to where this device mounts on an ss.
 

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2002 chevy trailblazer_ls
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99% complete 02 trailblazer ls with lq4 6.0 here. The crossmember will have to be modified , as the trans will be a few inches further foreward. The engine mounts I have were purchased from Nalley Brunswick GMC in Brunswick Georgia. The oil pan and oil pump pickup tube was purchased through eBay, as it is necessary if you have and want to keep 4x4. The driveshafts were ebay used units as well (just replaced u-joints) from any v8 trailblazer based (swb) truck, al la envoy denali, bravada, rainier, 97x 5.3, etc. Exhaust came from OBX, which fit beautifully. I also installed an ls hotcam kit, double roller timing chain, and high volume oil pump. The only warning I can give to anyone doing this swap is remember to use the correct o-ring for the oil pump pick up, as they are not the same.
Also, I have only 1 issue, and it's the ebcm/bpmv mounting on the driver's side frame rail. After the swap, with the headers installed, the driver's side exhaust practically rests on the abs pump/module. I have yet to see any photos as to where this device mounts on an ss.
Would you happen to have a parts list for this swap i have a 5.3 and a 4l80e tranny already. now i just need to get the other parts together. thanks for the help.
 

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2004 chevy trailblazer_ls
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6 Posts
Just seen this and noticed no activity for awhile, wanted to see if any updates were made.
 

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2007 gmc trailblazer_ls
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6 Posts
Just seen this and noticed no activity for awhile, wanted to see if any updates were made.
bump? just bought a 4.2 with knock for the sake of swapping it. done a few swaps in my life, just curious how bad cross members and wiring will be or was for anybody else.

i swear if i cant find anything online for this, ill document mine step for step so that there's never another living non V8 swapped TB -_-
 

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2007 gmc trailblazer_ls
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6 Posts
How are you coming along sean?
so far just getting lucky but not working on it for another ~2 weeks. i have 2 cadillac STS's that im carving apart and creating a single STS out of, and that project is nearing an end now.

After purchasing a 5.3 engine, 5.3 harness, 0411 ECM, and 5.3 TB oil pan, i found an entire donor Envoy to pull everything from. Nobody showed any interest in it for a couple of weeks, so I got lucky with the price - $1200 for the entire vehicle. Here in CO, vehicles go for 20% more than normal, so if you look at it as a $1000 donor, its not so bad.

I did tell the owner of the salvage yard that I want to fully take photos of the frame, as I keep hearing the frame is different, and that I might want to cut some pieces of it off for the project. He offered to lift it up on a forklift for me so I can get all of the pieces/photos I need.

I'll document the hell out of it as best as I can. There's sooo many TB's out there for so cheap that its a shame nobody else has already done this.
 

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2007 gmc trailblazer_ls
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to follow up, i have the engine, trans, harness, all of the 4x4 stuff, and i plasma cut the mounting system off of a donor. there's really no way in hell this wont work.

my plans got all derailed with work having me busier than anticipated this year, but im still planning on having this done prior to spring.
 

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2007 gmc trailblazer_ls
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man, nobody else beat me to it, yet?

so i moved, changed jobs, etc. garage is a wreck. i have the entire dropout assembly from a 5.3 trailblazer, i plasma cut the mounts off, in case i need them. i dont see how this isnt a relatively easy swap.

worst case/fears:

* axles are different, so it may overpower the diff. but thats a common thing to address
* fuel pump may be deficient, but a bigger pump & in-line regulator is no big deal

i dont even see why the gauges wouldnt work. im starting this in about 4 weeks, at my current availability.
 

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2002 gmc envoy_sle
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The motor mount brackets will need to be swapped to use the v8 motor mounts. The gauges should work fine with the 5.3 sending units. The rearend will work for now and may live for a long time depending on your driving. The drive shaft lengths will be different for the front and rear shafts due to the trans mounting location being different than the 4.2. I hear the v8 trailblazers and I6 trailblazers have different brake lines because the abs modules are in different spots. I have only read this and not confirmed in person. As far as the fuel line goes you should be able to get one from a v8 trailblazer from the filter to the fuel rail. I believe they are all returnless.

Definitely keep us updated of the swap progress. I will be swapping a 5.3 into my 02 before too long. I have done several LS swaps on several cars. This one seems pretty straight forward. I’m just going to buy a donor 03 or 04 XL with a 5.3 and take everything I need off and scrap the rest.
 

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Well my 4.2 liter inline 6 threw a rod this morning and i lucked out finding a 2004 5.3 liter for 400$ with PCM and complete harness, so now its time to start the swap, I've already got a pretty good idea of everything I may need
Only deal is the 5.3 came out of a pick up so I have to check my oil pan clearances, and im probably gonna just splice in the 4.2 BCM and Fuse panel into to 5.3 wiring harness I know it takes a little more time and its a hell of a lot more than anyone really wants to do but at the same time I'd rather do this than spend 600-1200$ on a complete wiring harness, and seeing as how i can't find a whole lot on anyone going thru with the swap because somehow they feel its not at all feasible, well I guess its about time to show you that if you want it you can do it
 

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Following this. I’ve got the SS rear end in my 05 TB Ext 4x4 and I drive a Silverado with the 5.3 and 4:10 gearing. I love the pickup the truck has with the v8 and would love to have that out of the TB. I’ve never done a swap but have access to most of what I’d need. Time seems to be the only thing in short supply! I’ve got a 3” body lift... will that help in terms of room under the hood? Also wondering what the cost has been so far on this for you, Sean. TIA!
 
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