'99 Silverado 4.3 to 5.3 Swap with 4L80e bonus

[stutaeng]

Well, I got that dang beast bolted up! I struggled! But got it done.

Also checked converter spacing. I used a 1/8" and 3/16" drill bit. The 1/8 went into the gap, but the 3/16 did not. And converter spun freely.

Even had my 9 year old son help me spin the engine to tighten TC to flywheel bolts to spec! Had to explain him the process but he got the idea...

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[stutaeng]

Got the tranmission crossmember modified. Not sure how this works on the GMT 400 (I think crossmember bolts directly to the frame and some trucks already have the holes set back?), but on the GMT 800 the crossmember bolts to some brackets that are riveted to the frame.

In my case, the bolt on the 4L80e mount was an exact 6" toward the rear compared to the position on the cross member for the 4L60e.

So I cut the steel tube crossmember and pushed the center portion back with some plate stock.

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[Erik the Awful]

On my stepside, the crossmember bolted directly to the frame. That made it really easy to build a lowered crossmember. Your crossmember looks like it will work, but I'd be a bit mindful of the lever action that spacing is going to create. The upside is that the actual mount is a couple inches back towards the centerline.
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[stutaeng]

Installed the wiring harness. Everything went well.

I didn't realize the transmission filler tube is not the same. Had to order a new one. GM part # 15832205. Not sure on the dipstick yet, if those are the same.

Ordering parts for this truck in the future is going to be fun!

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[stutaeng]

I went ahead and bought a 34" core radiator. It's not necessary. You can run your 27" core radiator and make it work. But I do want to add the engine oil cooler down the road, so ordered the 34" with engine oil cooler connections.

And the 34" radiator is required if you want to run efans also. I'm running the mechanical fan for the time being on mine...

Mine was looking like it could use a good power wash at the minimum, LOL.

Also compared the transmission dipstick to my daily driver 6.0/4L80e dipstick and they are identical in length, so I should be good on that.

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[df2x4]

When I was researching parts for my 4L80E swap in my red '97 I found the same thing. I could re-use the dipstick from my factory 4L60E, but I needed a different tube. Cool to see it's the same with the GMT800s.

 

[Erik the Awful]

Ordering parts for this truck in the future is going to be fun!

I can see it now. There's going to be so many swapped trucks that in thirty years people will be arguing over whether the LS was an option in the GMT400s. Vendors will be advertising parts for a '96 Chevy pickup with a 6.0.

 

[stutaeng]

I got that filler tube for the transmission. I did have to remove the crossmember and drop the tail housing again to weave it in. Then filled it with like 11 quarts of fluid. I had added about 1 1/2 qts to the torque converter.

I hooked up the battery and went inside the cab and realized there was some burn electronics smell, so I disconnected the battery. But nothing was working. Dead. I had a good 2A amp draw when I checked with a DVOM. Not sure if anything got fried...

Then I realized I put in the same fuse block from the V6! Doh!

I put the V8 fuse block and stuff inside worked again. Doors locked, windows, lights, etc. Dome light didn't work though.

And when I cranked nothing. I put a test light on the starter solenoid and it came on when I tried cranking. So after dinner I banged the starter with a hammer and the darn thing fired up!

It's missing one spark plug wire, the radiator and exhaust manifolds, so I shut it off immediately. I was thinking it was just going to crank... thought I had to get VATS deleted, LOL.

Had made beef barbacoa tacos for dinner, so I'll continue with the old girl tomorrow!

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[sewlow]

Had made beef barbacoa tacos for dinner, so I'll continue with the old girl tomorrow!

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https://www.gmt400.com/threads/whats-for-dinner.25059/

 

[stutaeng]

I didn't get much done on Sunday. Had a stud on one of the manifolds broken and tried the welding nut method and the stud kept on shearing off, until it was recessed into the surface. Luckily I had another manifold laying around. So both manifolds got installed, along with the Y-pipe and O2 sensors.

Installed the new radiator. I didn't mention it, but my transmission came from a 95' C2500 with the 2 cooler lines side by side. The later transmissions have one of the cooler lines going to the back of the case, and you need to extend one of your cooler lines. But in my case, no modifications were required to the lines. The lines went into the radiator just fine as well, even though it's a bit wider.

The problem is that the engine fires up and then immediately dies. I checked for fuel pressure and it drops off pretty fast to like 20 psi after a few seconds. I was going to go out and buy a new FPR, but I think I need to do more diagnosing. And I haven't gotten this ECU VATS deleted/reflashed either. But I think the fuel pressure issue needs to be addressed first?