the ls should be much eaiser than the suby. but nothing is cheap these days.
this could be a bit if a rabbit hole. on the engine side it's pretty standard ls. just not a normal cam grind and a little higher compression piston on the hybrid 6.0L, it's also aluminum. keep the piston compression in mind if you need to order new pistons for some reason when you get it apart.
all these ls engines from this generation have AFM. it's lifters that use oil pressure to deactivate cyl to save fuel. they all fail at some point, mileage and oil changes mattered most. usually getting stuck closed. so you get a loud tapping that can almost sound like knock. if you catch it quickly. (search YouTube) Lotta times you can just replace the lifters. but those lifters are sitting in a plastic holder, it's all that keeps them from turning, if they turn it eats the cam lobe and pours metal thru the engine. on a non hybrid most do a AFM delete kit. on the hybrid, I don't think I've seen a non AFM cam grind for it. you could probably have one custom ground for it but I've not checked. so you'd end up needing a oem cam and lifter set.. they are getting kinda pricey.
rest just search YouTube for any ls rebuild video. it's pretty common.
now for the hybrid stuff.. being an 08 you really need to know when the hybrid battery was changed. if it's oem, it's toast. no way around it and these trucks do no run without a good hybrid battery. it's a nickel metal hydride, not the newer lithium ones. so it's 80s tech. same battery used in prius hybrid, same Japan factory and all, just longer and more cells for higher voltage. but that said, it's in a 6k lbs truck so it was over worked and the cooling system wasn't really up to it. with a few software updates along the way they tried to limp them along to avoid replacing them all under warranty. but it's not good, just factor in replacing it if it's not fresh. the truck will try will try to drive on battery power and start the engine at the same time, which pulls a ton of amps, if the battery isn't good it struggles to do both, bucks all around, sometimes doesn't start. it's ugly and ******* everything but most people try to avoid replacing it because of the cost, hoping it's something else and throw parts at it. I've seen nightmare story's of dealers not knowing what's wrong and the owner end up with a 10k$ bill and a truck that runs bad still. a green bean replacement battery used to be like 2500$ and they will come swap it out at your home for you. may have gone up thou.
is it worth it? I really enjoy mine.. but I'm also into the tech. I'm a fleet mechanic by trade and my fleet is being converted to electric equipment slowly. so for me it all crosses over. I enjoy it, it gets honest 20mpg with the wife daily driving in the city soccer mom style, runs 87 octane. gets 25mpg on the high way. tows my fun car on the trailer great and still gets 13mpg doing that. my buddy's bearly get that in their diesel trucks towing the same load. from what I can tell a non hybrid 5.3 would get 12-14 around town like we drive it. the 6.2L requires 93 and gets a touch less than the 5.3
in the end it helps if you enjoy trouble shooting any random wiring issues that come up. hybrids are super picky, since they are scared of anyone getting shocked, the slightest wiring issue they shut down.
the tranny is very good, it's a collaboration with gm, dodge, and a German company. it's a scaled down copy of a hybrid bus tranny made by Allison. but if no one changed the fluid for 150k miles, and the hybrid battery pack driving around bucking and struggling, it can be a bit of a crap shoot. also parts are hard to come by, since it's discontinued at this point, but some are listed, finding someone to rebuild it might be harder. a few used ones pop up forsale thou.
it's pretty much impossible to say if you can get it running for 3k without knowing more. non hybrid guys here seem to spend 2k or so on a AFM delete kit, another guy had a shop install a jasper reman engine for like 10k$, those are the normal trucks, I'm guessing the word hybrid would run that cost up a lot of you had to have a shop work on it. it is possible doing it all yourself, but you'd need to open it up to really know. I bought a good running 135k mile 2011, I went in knowing it would need a hybrid pack so I upgraded my batteries to lithium cells. a bit untested, and there's a huge debate on the prius boards if they will last long term. i read up and decided it was interesting enough to try it out. but point being I have spent over 3k on a good running on haha. but again I really enjoy the truck, plan to keep it forever and feel like it's a shame they didn't keep going with the hybrid system using today's battery tech and that new turbo 4cyl. they'd have a suv that got 30mpg without compromise.
