1998 k1500 6.0 4L80 swap

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KevTemp

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Looking for info on swapping a 6.0 and 4L80 into a 1998 K1500. I have both complete trucks.both are 4x4. I wanna use motor,trans,transfer case and pcm from the donor truck. Questions I have are motor mounts, transmission mount and driveshafts. I think I can newer pcm to work everything on the 98. If I use the dirty dingo mounts, which way to slide the mounts. Forward or back? And would that be enough to make driveshafts work? First time here and I’ve already seen a lot of useful information. Thanks for the help !!
 

stutaeng

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I don't know all your answers, but you seem to have a solid plan. Is the newer transfer case mechanical shift or electronic shift?

Regarding the driveshafts: I don't believe your original driveshafts will work. Reason is the 4L80e is longer than your previous transmission (around 3"?) and will put the transfer case further back.

You will also need conversion yokes for the driveshafts. The spline count is different between your 1500 and the LS/4L80e yokes.

The LS is like 1" shorter or something like that over the SBC, so you locate the LS back of the engine to the original location of the bell housing.

I kept saying LS, but I'm guessing it's an LQ4, right? You know what I mean.
 

L31MaxExpress

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I don't know all your answers, but you seem to have a solid plan. Is the newer transfer case mechanical shift or electronic shift?

Regarding the driveshafts: I don't believe your original driveshafts will work. Reason is the 4L80e is longer than your previous transmission (around 3"?) and will put the transfer case further back.

You will also need conversion yokes for the driveshafts. The spline count is different between your 1500 and the LS/4L80e yokes.

The LS is like 1" shorter or something like that over the SBC, so you locate the LS back of the engine to the original location of the bell housing.

I kept saying LS, but I'm guessing it's an LQ4, right? You know what I mean.
@Supercharged111 should be able to guide you on how to get a 1500 transfer case hooked up to a 4L80E. If I recall the input adapter has to be swapped.

ICT Billet makes adapter mounts that are adjustable position. On the G20 I used them on, I took the original clamshell mounts, heated the hump on top until it was cherry orange with a map gas torch and flattened them with a 2 lb mini sledge. Some people grind them down, but I wanted the material in place for strength.
 

Supercharged111

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If keeping original transfer case, input shaft and bearing need changed out but OP indicated he wanted to use the donor t-case. If using donor t-case, I would imagine it has a 32 spline output like the 4L80? Not sure on that, but if so then would either need to add a 32 spline yoke to the existing shaft, which would still need shortened, or just have the donor's shaft modified to the appropriate length and skip the whole conversion joint. When you just 4L80 swap one of these trucks, the rear shaft needs shortened and front lengthened, therefore if you can slide the motor forward you'd be golden. You can pin the 411 into the existing harness, but going to need to add in the coil packs, injectors, and some other stuff.
 

KevTemp

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I don't know all your answers, but you seem to have a solid plan. Is the newer transfer case mechanical shift or electronic shift?

Regarding the driveshafts: I don't believe your original driveshafts will work. Reason is the 4L80e is longer than your previous transmission (around 3"?) and will put the transfer case further back.

You will also need conversion yokes for the driveshafts. The spline count is different between your 1500 and the LS/4L80e yokes.

The LS is like 1" shorter or something like that over the SBC, so you locate the LS back of the engine to the original location of the bell housing.

I kept saying LS, but I'm guessing it's an LQ4, right? You know what I mean.
Yes it’s a q4, mechanical 4x4 shift and I was gonna swap Rearend also so everything should be the same on that end of the drive shaft. Is there not enough play in that shaft so I wouldn’t have to cut it? But the transmission crossmember stays the same?
 

stutaeng

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Yeah, I also understood OP wanted to keep the transfer case. I would do the same instead of swapping output shafts to his existing TC.

Depending on the donor TC, probably better to keep it to keep electronics happy. Lengthening and shortening the DS I don't think is a big deal, just find a local shop.

The transmission crossmember will need to slide back.
 

KevTemp

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So with the adjustable motor mounts, do I slide engine towards the radiator or firewall? Also are there adapters for fuel lines? Thank y’all for all the info
 

Supercharged111

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So with the adjustable motor mounts, do I slide engine towards the radiator or firewall? Also are there adapters for fuel lines? Thank y’all for all the info

Slide towards the radiator. For the fuel, it's been so long I can't remember where I got the fittings, but I went the expensive route.

This is an Earl's fitting that clicks on the rail.


And this looks like it would fit the line on the truck.


While I don't have an LS motor, my marine intake uses the same fittings.
 

KevTemp

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Slide towards the radiator. For the fuel, it's been so long I can't remember where I got the fittings, but I went the expensive route.

This is an Earl's fitting that clicks on the rail.


And this looks like it would fit the line on the truck.


While I don't have an LS motor, my marine intake uses the same fittings.
Where did u find a marine intake!! I’ve be been looking for awhile. Which is half the reason for the swap. Other is, I’m done with the 4l60. This would be number 3. I figured I could swap everything for the same money to rebuild trans. Having both complete trucks is almost a no brainer now lol.
 

Supercharged111

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Where did u find a marine intake!! I’ve be been looking for awhile. Which is half the reason for the swap. Other is, I’m done with the 4l60. This would be number 3. I figured I could swap everything for the same money to rebuild trans. Having both complete trucks is almost a no brainer now lol.

I got mine off of eBay. . . back in 2012 when you could still find them. If you were to sneak a narrow-pattern cam into that 6.0, you could pick up a lot of torque. I feel ya on the 4L60, the first time mine broke it got dumped for a 4L80.
 
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