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5.3 swap - ???'s for folks that've been there/done that

2K views 3 replies 3 participants last post by  scorean 
#1 ·
Hey all you 5.3 swappers, I'm about elbow deep into my 5.3 swap and had some questions before I get in over my head... I've done a bunch of reading on the interwebs and watched plenty of YouTube vids that all seem to gloss over certain "easy/obvious" stuff or just ignore it all together.
Here's the situation:
1) My plan is to install the engine and transmission from the Envoy into my 95 AWD Astro. I know the front diff is going to be a clearance issue that I'll just have to work around and deal with.
2) I've got a 2004 Envoy donor that ran well and everything seemed to work decently enough.
3) I've got most of the front end removed and a bunch of the harness on the engine unplugged and labeled.

Questions:
1) What is my course of action with the fuse block? Most of it runs through the firewall and can't be unplugged. Where do I go from there?
2) What controls the tranny? Does the truck have a PCM that runs it all or a separate ECM and a TCM?
3) If TCM, where?!

That's a good start... If I can figure out how to unplug this thing and get it out of the Envoy, I'll feel like I'm well on my way!
 
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#2 ·
scorean said:
Questions:
1) What is my course of action with the fuse block? Most of it runs through the firewall and can't be unplugged. Where do I go from there?
I can't answer your question, but assuming you get the donor box out in one piece, where will you put it? The main astro harness does not have a very large hole to go through. You might have to cut/de-pin the box to get it out, but then you can reinstall completely in the van.

I did a carbureted swap, so I won't be much help here.
 
#3 ·
scorean said:
Hey all you 5.3 swappers
Haven't done this swap yet, does that disqualify me from answering? ;)

scorean said:
1) What is my course of action with the fuse block? Most of it runs through the firewall and can't be unplugged. Where do I go from there?
Keep your existing fuse box, 100%. You will add the wiring for the 5.3 PCM that you will mount somewhere in the engine compartment, but don't mess with your fuse box.

scorean said:
2) What controls the tranny? Does the truck have a PCM that runs it all or a separate ECM and a TCM?
The 5.3's PCM controls the transmission.

scorean said:
3) If TCM, where?!
Part of the PCM.
 
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