2015 doesn't have a 4l80e, it'll have at least a 6l90, but could be something else. rpo code sticker in the glovebox will indicate what transmission it has.

You could pull the 6.0, change some parts in it (crankshaft reluctor wheel, camshaft, maybe some other stuff, intake manifold), and then install it into your '00, and then tune the ecm to run it, that would be expensive and time consuming for no real benefit.

The transmission from the '15 will be expensive to get into your '00, you'd need to find some kind of standalone controller for it, and then rig it up somehow.

If you want to put a 6.0 in your truck, sell the '15, and find a gmt800 truck w a good 6.0 engine, lq9 is a bit more powerful than an lq4 (these are the rpo codes for the version of 6.0 engine the truck has). Then if you want, build up that 6.0 and install it in your '00. And then use your 4l60e or swap in a 4l80e, but you'll want to build either of them for more power (as well as a new torque converter).

 

Davester3500. Man, I can’t thank you enough for saving me from the mistake I was about to make. As I dig in to the project (researching along the way as I go) I know I’ll gain a better understanding of everything, but you saved me from diving in the wrong pond from the start. Much appreciated brother!

 

How much money do you want to invest in this?
Its possible to fit the 6.0/6L90 into the 2000. but you will need the 2015 ECM to control the engine and communicate with the TCM in the Transmission.

But another option for you.
The 6.0 in the 2015 has really good cylinder heads. I would sell the 6L90E and buy a 4L80E. It bolts in no problem.
Tear the 6.0 down and swap to a 24x Reluctor and 1X cam sprocket, going to want to do a cam swap anyway.. That way the LS1B Pcm from the 2000 can control it.
Use the 6.0 Intake and get a 4 bolt to 3 bolt adapter to use your 2000 Throttle Body. Now you have a really simple setup that makes good power.

 

Another option is to drop the 6.0/6L90 into the 2000 and use a Holley ECU to control the engine/transmission and just piggy back sensors so the cluster works.

 

RDF-1 Thank you so much for replying to this. Having options is a great thing before I dive in with money. Much appreciated, friend.

 

Theres several different ways to go about doing what your trying to do. Its just how much money do you want to spend.

 

RDF1- I hate overstepping with cont'd questions, but you're right...gonna take some money for sure. Working two jobs, I unfortunately won't have lots of time to get into the build myself (gonna try as best I can to do what I can handle personally) but the fact is I'm gonna have to rely on local help (shops, tuners, friends) to help me achieve it. That's gonna cost me. To give you a better idea...I'm the original owner of the truck, bought it brand new in 2000. Drove it stock for a quarter century. Now, all I've done to it so far is install the 4/6 IHC lowering kit, wheels and tires. So, I'm really still at square-one.

I don't wanna race the truck, I just want a torquey, fun to drive street truck (anywhere north of 500 hp would be the goal, naturally aspirated) that I can get nasty with every once in a while. Get on it and raise hell from time to time. Daily drive it to work. Play when I feel like it. But as far as money goes, it's gonna cost me a good bit of it, so I'm hoping to make some of the right decisions the first time. I plan to put a 4.10 gear in it soon, with limited slip locker. Which is why I'm curious of your thoughts...If it were your truck, would you want to run the 6l90 (properly tuned) or is there any advantages / disadvantages with running that instead of putting a 4l80 in it. I haven't seen many street truck builds with the 6l90 (haven't seen any on youtube, in fact). Curious what your thoughts are on this. Thanks man

 

Me personally id rather have the 4L80 unit. Its much more simple transmission. With the right setup it will run great!
The 6L trans are ok but they are expensive to build and they aren't my favorite. Ive built and tuned a ton of cars and trucks.
The most reliable are the simple builds.
My favorite is a small cam that is easy on valvetrain, turbo charged, 4L80E, and the right gear ratio for whatever tire size you want to run.
Its nothing for one of those setups to make 650rwhp and be a blast to drive, last a really long time and will absolutely fly plus still get good MPG.

 

RDF1 Thanks so much man