Looking At A 2005 Z71 4x4

[CountKrunk]

There's no such thing as ac "just needs a charge". It's broken in some way or will slowly leak out that charge. My $.02

 

[TotalyHucked]

^I'd also agree with that. It may take a charge for a little while, but it'll need a rebuild too. Mine works well right now but the hard line under the hood is all green, the o-rings are giving up on the ports. It'll get gone through with a new orifice tube, drier and whatever else it needs this summer

 

[JamesSam]

So that being an '05 ECSB Z71, it could be an L33 truck. Get a picture of the RPO sheet if you can. L33 was the Hi-Po 5.3 with an aluminum block, flat top pistons, 799 heads and hotter camshaft. Made like 315hp instead of the regular LM7's 295hp.

What's been mentioned above is mainly just maintenance stuff that can/will happen with any car. Wheel bearings don't go out any sooner than anything else (my current truck has 187k on it and the entire front end is 100% original). Engine gaskets are also considered a maintenance thing at this age. Every seal/gasket under my truck needs to be replaced at this point but I expected that/knew it when I bought it. Engine is coming out for a reseal soon, trans was rebuild just before I bought it, T-case needs a reseal and axles are getting done now.

Gauge cluster stepper motors like to go out, so if the oil pressure gauge is pegged or moving around erratically, fuel gauge doesn't read, speedo is stuck in a spot, etc, get the gauge cluster rebuilt. That runs ~$175 here for a basic rebuild, there's also guys online that can customize them any way you like. Steering wheel buttons died/stop lighting up. Can find them online easily.

Transmissions are the same as other maintenance items, just expect a rebuild at some point. That will have the 4L65E in it, which is slightly stronger/upgraded from the 4L60E. Depending on mileage, it's likely been rebuilt already or will need to be at some point in the future. They're perfectly fine behind a stock 5.3, don't buy into the "60E's are junk transmissions" online BS.

Rear axle is a 8.6 10-bolt, basically an evolution of what's in your square. Plenty durable for a half ton truck.

Front axle is an AAM 8.25 IFS differential. You'll likely have 3.42 gears (GU6 code - the base, most common gear in '05-up Z71s) but 3.73 (GT4) or 4.10 (GT5) was optional. If it's a bench seat truck, it could have either the push button 4wd on the dash or the manual lever in the floor. If it's a factory bucket/console truck (easy way to tell is if it has arm rests, that's factory. If it doesn't have arm rests, the console was added), it'll have push button 4wd. The push button will have an Auto4wd option, don't use this. Ever. It's really hard on the transfer case and bearings. Just use 4hi/4low as needed (same as your square, only in slippery/offroad conditions).

Bose was an option and is a pretty darn good sound system for a stock setup. Mine works perfectly fine, even at 20 years old. There's a tiny little 5.5" sub in the console, tweeters on the a-pillars, 6.5" round speakers in the front doors and 4x6"s in the rear doors.

The transfer cases are known to have "pump rub" in higher mileage trucks. If it gets bad enough, it'll rub through the case and you'll lose all your fluid/burn up the T-case. Same as a trans, eventually it'll need a rebuild and a "pump rub kit" is a good thing to throw in while you're at it. Not a hard job.

Another maintenance thing, check the u-joints. These have big aluminum driveshafts (5in diameter IIRC), you don't want that getting slung out.

Extended cabs tend to not seal as well as crewcabs at this age. My last one needed all the door seals and door pins/bushings. All the seals are available from Precision (about $600 for all of them) and the pins/bushings are available from several different places. Make sure to check the rear door hinges closely. If they don't shut well/are badly misaligned/are tearing out of the door, new hinges are like $175 A PIECE! I just recently found this out.

But realistically, what these do need at 20yrs old/200k+ miles is simple and cheap compared to most other vehicles. These are the most comfortable/reliable vehicles GM ever made IMO, there's a reason so many are still on the road and why I keep coming back to them. I'll never be without one from here forward

Thanks @TotalyHucked Zach for all the info. I will be going to look at and drive the truck soon. The snow here is kind of holding everyone up just enough to get in the way. I hope I can go see it Saturday. I just got a positive response from the owner and plan on taking pics to share.

 

[75gmck25]

Gauge stepper motors were a problem on these GM trucks, and also on the 2005 Mustang GT I used to have. Sometimes they are slow to start up, so they read too low, and sometimes they just stick at one reading. Really confusing when one or two gauges is totally useless.

New stepper motors are relatively cheap ($30-40 for the entire set), but you need decent soldering skills to take the old ones out and solder the new ones in. I did it on my Mustang GT and it took me a couple of hours because I was being careful. The guys advertising on the internet will do the job for you, but you need to mail the entire cluster to and from their shop.

 

[bigcountry78]

everyone has pretty much covered everything, but I’ll add my 2 cents. We have a farm truck, 2001 Silverado bought new. 315,000 miles and it just blew a head gasket, otherwise everything is all original. Even the transmission. Slightly older truck, but the same generation. I personally bought a 2006 Silverado, single cab short bed z71, in 2008. It had 43k miles. I drove it daily until 2014 or so, when I sold it because car seats don’t work in a single cab. It had 180k on it when I sold it, and was just starting to shoot a small puff of blue smoke on startup. The only trouble I ever had, and I mean the ONLY thing, was front wheel bearings. The first one went at 75k, and I ended up doing 2 more while I had it. That was it. Oh, and an abs sensor on one front wheel. Otherwise it was the best truck I have ever owned, hands down. Now I have a 2009 Nissan Titan crew cab. I bought it because it was a good deal at the time, but if a meteor fell on it tomorrow and I had to buy a new truck, it would absolutely be a 2003-2007 “classic” crew cab. I prefer the 99-02 rounded front end, but they didn’t come in a half ton crew cab.

 

[bucket]

Dang, y'all are bringing up a bunch of stuff that has never went wrong yet on our '00 2500 Suburban. With nearly 300k on it, it's original for the most part. One fuel pump, two water pumps, a power steering pump, one tie rod end, one ball joint, one window regulator, one belt tensioner and more recently, a radiator. Oh yeah, it's had both front wheel bearings replaced as well. Oh and a blower resistor, lol.

It does now need one more ball joint, idler/pitman arms and an alternator bearing is getting pretty noisy on a cold start. But for nearly 300k, it's been pretty good.

I did give up on the AC several years ago. It needed charged every spring. The AC belt tensioner seized basically every year and it would throw the belt. There was one spring where I charged it, then a few days later, it threw the new belt I had just put on (the previous one was cheap and squeaked) because the tensioner started sticking even though it was perfectly fine a few days before. So I replaced those parts again. Then a few days later, the blower motor quit working. I replaced the resistor and we had cold AC for a few more days... right up until the compressor started chattering and slipping the new belt. I got mad, cut the belt off and told my wife that it's going to be 4/60 AC from then on out.

 

[Frankenchevy]

These early 5.3 ls trucks are nice. My dad had a 2003 z71. The cat eye did raise some eyebrows. We didn’t mind it in the dark green color. I remember I’d drive it when I’d be back in town visiting and I thought it was pretty snappy back then. 300hp used to feel quick in a truck, especially coming from a 1997 burb with a 255hp 350…Those were the days.

 

[legopnuematic]

I’d say the GMT800 platform is pretty darn durable, and in some cases, even thrive on neglect.

Like Stanley’s 8.1 truck:

Over 500k, 8.1, 6 speed.

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I am not sure if it’s all of them or only certain ones, but they have plastic adapters to the heater core on the firewall that break at random, I think Dorman sells a metal version or just remove and clamp the hoses without the quick connect.

 

[Drauka99]

Only issue I have ever had with my 04 is the AC/Heater is the weakest system I have had in a GM vehicle. my 04 Blazer and 97 GMC, 2001 and 2010 cars all have better AC and heat. Actually the heat on all of those will run you out of the vehicle after a bit. the AC in the 97 will freeze you.

 

[mxer147]

My 04 Duramax (50K) has been mostly trouble free with the exception of: stepper motors, rear Bose speaker, rotors rusted because it sits a bunch, clear coat burned off, headliner delaminating; I bought it brand new with the intention of never buying another truck in my lifetime. In the middle of the summer, it can run a little hot towing a heavy load up the mountains. I love driving it but it can be a little more expensive compared to a more fuel efficient car. It’s actually just getting broken in and the fuel mileage has been increasing. I keep it well maintained including resolving the transfer case rub issue.

 

[bigcountry78]

Dang, y'all are bringing up a bunch of stuff that has never went wrong yet on our '00 2500 Suburban. With nearly 300k on it, it's original for the most part. One fuel pump, two water pumps, a power steering pump, one tie rod end, one ball joint, one window regulator, one belt tensioner and more recently, a radiator. Oh yeah, it's had both front wheel bearings replaced as well. Oh and a blower resistor, lol.

It does now need one more ball joint, idler/pitman arms and an alternator bearing is getting pretty noisy on a cold start. But for nearly 300k, it's been pretty good.

I did give up on the AC several years ago. It needed charged every spring. The AC belt tensioner seized basically every year and it would throw the belt. There was one spring where I charged it, then a few days later, it threw the new belt I had just put on (the previous one was cheap and squeaked) because the tensioner started sticking even though it was perfectly fine a few days before. So I replaced those parts again. Then a few days later, the blower motor quit working. I replaced the resistor and we had cold AC for a few more days... right up until the compressor started chattering and slipping the new belt. I got mad, cut the belt off and told my wife that it's going to be 4/60 AC from then on out.

I had an 04 briefly that gave me ac troubles. I eventually did what you did, cut the belt and move on. But I only had that truck for about 6 months. The 01 we have, and my 06 never gave any ac troubles. I only had my 02 for about 6 weeks before it was totaled, so I don’t count it.

 

[TotalyHucked]

Dang, y'all are bringing up a bunch of stuff that has never went wrong yet on our '00 2500 Suburban. With nearly 300k on it, it's original for the most part. One fuel pump, two water pumps, a power steering pump, one tie rod end, one ball joint, one window regulator, one belt tensioner and more recently, a radiator. Oh yeah, it's had both front wheel bearings replaced as well. Oh and a blower resistor, lol.

It does now need one more ball joint, idler/pitman arms and an alternator bearing is getting pretty noisy on a cold start. But for nearly 300k, it's been pretty good.

I did give up on the AC several years ago. It needed charged every spring. The AC belt tensioner seized basically every year and it would throw the belt. There was one spring where I charged it, then a few days later, it threw the new belt I had just put on (the previous one was cheap and squeaked) because the tensioner started sticking even though it was perfectly fine a few days before. So I replaced those parts again. Then a few days later, the blower motor quit working. I replaced the resistor and we had cold AC for a few more days... right up until the compressor started chattering and slipping the new belt. I got mad, cut the belt off and told my wife that it's going to be 4/60 AC from then on out.

Forgot to mention the blower motor resistor. If the blower motor stops working on level 5 but works on everything else, it's the resistor. Or if it doesn't work at all. Quick and easy fix under the pass side of the dash.

Also another thought. There are 2 different climate control systems, the manual "slider" style:

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And the digital style:

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NOTHING INTERCHANGES. THEY ARE 100% DIFFERENT SYSTEMS. The manual slider is pretty reliable. The digital is hit or miss, I've had both in low and high mileage trucks. The digital, the temp control knobs will get to where they won't really adjust the temp. You'll spin them and it'll stay the same or barely move, you have to spin the VERY slowly to get the temp to change. Usually, you can pop the knobs off and spray some electrical cleaner in there, let it dry and put them back on and be ok. Also, the display will die sometimes or some of the buttons will quit working or the whole head unit will die. You'll have to replace the headunit at that point. YOU CANNOT CONVERT TO MANUAL/SLIDER. As I said, the whole system's different. Head unit/ducting/blend doors/harness/all of it from my research.

The manual is much more reliable. It can also die and you'll have to replace the headunit but they last alot longer. The LEDs will die in all of them (and the steering wheel controls, and the door switches, and the gauges lol) but they'll prob still be functional. My current '05 has the slider style and other than some LEDs being dead it works great.