Quick 2wd GMT800 Learn Me

Going to look at a regular cab short bed 05 Silverado this afternoon and need a quick learn me. It's a mid level trim truck with ~140k from Georgia, so i am hoping it's as clean and rust free as the ad claims it to be. I've got some general familiarity with the platform and it's general weaknesses (rust in the cab corners/rockers/brake lines, funky instrument cluster stuff, general 4l60 weakness), but have a few specific questions and want to make sure I'm not missing anything.

First, seller claims it to be a 5.3, but I know visually the 5.3 and 4.8 are virtually impossible to distinguish. What's the best way to tell the difference? Decode the VIN? Honestly I don't care all that much, just figured it could be a good bargaining chip.

How about telling if it has a Posi? Or was the G80 locker the only option? Don't really wanna bring the jack along and spin the rear tires, so again is there a VIN code for this?

How about determining health of the tranny? Smell the fluid and see if it does anything funky on the test drive? I'm admittedly kinda clueless when it comes to autos.

Anything else I'm missing?

If the RPO sticker is still there in the glove box This page has the codes to look for on the engine. Here is a site that has the rest of them. Checking fluid and test drive is the best answer I have on the transmission.

8th digit of the vin is engine code. They also normally have a factory info sticker on the airbox or edge of the hood. Smell the trans fluid and pay attention to the 2-3 3-4 shifts. They tend to slip on thos shifts if there worn out.

Well, here's the verdict. Mechanically I think the truck is in pretty good shape and seems to have been kept up. Fluids all looked good, trans fluid looked pretty fresh and certainly didn't smell burnt or anything, shocks are new, brakes are newish, had the water pump done last year. Didnt find any major leaks. Rockers and cab corners are solid, brake lines looked good from what I can see, some surface rust on the frame, but overall definitely looks like a southern truck underneath. Drove well, steering is tight, tranny didn't slip at all that I could tell and it kinda hauls ass with the 5.3. Bit of a thunk coming from the steering column (I think, hard to tell exactly where it came from but I was feeling it through the wheel) over some bumps, but still steered fine.

Cosmetically it had some issues. Guy warned me before I got there that it was a bit dirty and it definitely was. Says he would get it detailed prior to sale if i bought it. Guy just had back surgery, or he would have cleaned it up himself. Some of the trim around the dash had come loose at the one corner and the overhead consol was missing a screw. Had a big scrape down the passenger side, with corresponding dents in the front QP and rear lower bedside just in front of the bumper. That was the biggest issue, but lots of other small scratches as well. One of the front turn signal lenses was cracked and the other had condensation in it.

Got pics of the RPO codes and it's got the G80, 3.23 gears, and tow package. He's at $5k and I told him I'd think about it and let him know. I'm in no huge rush to buy and it's not in spectacular shape, but it is decent and kind of a hard to find configuration.

Steering shafts do make noise as they wear. Replacement shafts are available and solve that problem. Sounds decent, price is okay. I forget how much trucks go for, and standard cab short beds are getting harder to find. Body parts and lenses are easy to get for GMT800s, so that part would be easy. On a related note, have you check Texas? They seem to have good trucks for better prices than the southeast.

The steering column clunk is very common. You just need to work some grease into the slip joint. There is a kit available at gm dealer parts department. It has a little pillow pack of grease and a plug that goes in the shaft to help force the grease through the slip joint. Its a really easy job, like five minutes. I think theres a tsb out there somewhere.

In reply to gearheadmb:

Good to know! Thanks for the info.

In reply to 81cpcamaro:

I do check Dallas and Houston Craigslist every once in a while, but it would be hard for me to make time for a fly and drive within the next few months. It is a decent truck, though. Price is probably about right, honestly, though not a screaming deal or anything. They are quite hard to find and the nicer ones do seem to command more money when they come up. I like the RCSB proportions a lot and think it would work well for me as a multi purpose daily. Really on the fence.

What's the scoop on the G80 locker? I know they have a bit of a reputation, but I'm not really too familiar with what the dig is on them.

That sounds about as good as it gets with a GMT800 at this point, the interiors weren't the greatest (especially durability wise, the GMT400 interiors seemed to hold up better) and they're all 10+ years old at this point.

G80 gov lock, acts like an open diff until you get enough wheelspin to engage it. It will allegedly explode if you do your best to break it, avoid really hard shock loads and it will be fine.

In reply to BrokenYugo:

I agree with the plastics, but the cloth seats in the 800 hold up 10x better than the 400's. I swear you can't wear them out.

As for hte G80, dad's got ~213k on his. still works fine. I wouldnt' be concerned about it.

Is the engine multi/variable displacement? Those tend to be the weak link of the 3rd gen engine family.

In reply to Brian:

Nope, those didn't show up in the trucks until the GMT900 came out in 07 I think. IIRC, those are actually the 4th gen engines, but don't quote me on that. This is just the good old LM7.