Wanting to buy a GMT400, how old is too old, and years to avoid? (discussion)

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Pinger

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Mine is a 1999 C2500 Suburban not a pick-up and is the only GMT400 I have ever driven so I can't make comparisons. What I can say is that I appreciate what modernity it has and though I'm probably tempting fate here - the additional electronics haven't caused me any grief.

The two things that spring to mind that plague Vortecs are the injector/spider set-up and the inlet manifold gasket. The injectors aren't a concern for me (as I run on LPG (propane)) but they do get slated on the forum. The inlet manifold gasket I had to replace on mine after only 45,000 miles. Any sign of leaked coolant around the manifold usually points to it failing and as pretty nasty things can happen if it fails internally (coolant in sump or worse, a cylinder filled with coolant and hydraulic lock on attempted start up causing a bent conrod) best not neglected.

Mine took a bit of sorting just to get things working right (nothing major though) and the truck is the better for it. At 23 years old that's to be expected and on that point you are going in with your eyes open. Happy hunting!
 

HotWheelsBurban

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I've had a '99 C1500 Suburban for 9 years now, it's actually the second one in the family. First one was a good truck, but got hit bad in a wreck and was totalled. Got this one w/the hard fought insurance payout. It's a better truck, doesn't leak as much as its predecessor.
Just picked up a '97 crew cab long bed 1 ton, with the same 5.7 Vortec and half the miles my Burb has. I had been looking for a 2500/3500 truck for several years, but this one popped up when I was able to make the deal happen.
One thing I will say about the big trucks: with the hydro boost brakes and steering assist, you need to closely watch the fluid level! And if you drive it and have a hard time keeping it stopped at lights, like it keeps rolling or just won't stay still, the HB may be fixing to go. They have a weep hole in the base of the unit, and if internal seals are bad it'll leak there. This happened on mine, soon after purchase.
 

ralmo94

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1995 is the first year for PWM torqconverter lock up, Wich means earlier trans are different both 4l80 and 4l60. Obd1 TBi is cheaper to mod, you can get a memcal adapter with a socket and change chips out as you need, cams are flat tappet and a lot cheaper, I bought a cam, lifters, and timing and valve springs kit for a 94 and only spent about $130

The fuel pressure can be cranked up if disired to meet up demands, but for hauling and truck stuff a low rpm torq machine is easy and cheap
Just make sure you run zinc and 10-30

If you get into the computer tune, all years can take a ground signal to the cruise control pin and use a different shift schedule.
 

DerekTheGreat

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I'm a TBI & "Kept it stock" kind of guy, so my vote is '92 to '94, stick shift two-tone paint schemes. Swap the composite headlights for the four eye look. Better looking interior, no Kelsey-Hayes four-wheel ABS and while not OBD II, you can still connect a scan tool to it and see live data. Easier to troubleshoot and keep going as they have fewer sensors. Engine bay looks cleaner as well. 454 or 350, I liked both. Although if you're going to drive it every day and only tow occasionally, I recommend the 350. Mine does just over 19 mpg on the highway at 70 mph.
 

AuroraGirl

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based on the OPs needs he expressed, I would say a half ton with out rusted frame and with the best brake options possible, but the only issue I think is that his "2000 payload" desire may not be safe/met with a 4x4 half ton, but im just guessing. Would be wise to have new leaf springs and assist type things( like load assist springs or bumpers etc)
 

Schurkey

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1500s are fine...provided you don't have structural rust, and you deal with the crappy brakes and rear axle, especially on the early-model-year, single-cab (JN3) trucks. JN5/JB5 brakes are better, but still have the horrible leading-trailing rear drums. And almost all 1500s will have the weak 8.5" rear axle.
 

AuroraGirl

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1500s are fine...provided you don't have structural rust, and you deal with the crappy brakes and rear axle, especially on the early-model-year, single-cab (JN3) trucks. JN5/JB5 brakes are better, but still have the horrible leading-trailing rear drums. And almost all 1500s will have the weak 8.5" rear axle.
Maybe a light duty 3/4 ton is a good idea then

The half tons are the ones known for snapping behind the cab, right?
 

thx1138v2

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I have a '94 I bought new off the lot. It's a 4.3L V6 Fleet truck with 250,000 miles on it. No razzle dazzle, just a plain Jane truck. 4.3L engine, 4L60e transmission, GU6 - 3.42:1 differential, AC, Radio.

The down side is it is getting old and even the junk yards only hold them for so long so getting parts is beginning to be a problem for me. Crank windows - not electric. It will pull a load but not much.

The up side is that they are very simple trucks, e.g. no air bags and attendant collision sensors, no window switches, motors, etc. to go out. Change the oil and other fluids as specified in the owners manual, service the brakes and tires as needed and just keep driving it down the road.

OBD1 vs OBD2: I've been able to keep it running for 28 years without OBD2 diagnostics so there's something to be said for simple systems.
 
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packer0440

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I would focus more on getting a good truck vs the "right" model year; I wouldn't regard any year of the GMT400 to be "bad." If it has what you want and isn't rusted to pieces or completely worn out, go for it. I like the TBI system, but there is nothing wrong with the later models; I'm just willing to trade a little power for more simplicity. There are very few jobs on these trucks (especially TBIs) that can't be accomplished by someone with basic mechanical/electrical knowledge and basic tools.

It is also a big plus to have large numbers of these trucks in salvage yards to pick parts off of that are NLA or expensive otherwise. I will note that at least in my area, there seem to be many more of the vortec trucks in the yards these days than TBIs. Not sure if this is the same everywhere.
 

HotWheelsBurban

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I would focus more on getting a good truck vs the "right" model year; I wouldn't regard any year of the GMT400 to be "bad." If it has what you want and isn't rusted to pieces or completely worn out, go for it. I like the TBI system, but there is nothing wrong with the later models; I'm just willing to trade a little power for more simplicity. There are very few jobs on these trucks (especially TBIs) that can't be accomplished by someone with basic mechanical/electrical knowledge and basic tools.

It is also a big plus to have large numbers of these trucks in salvage yards to pick parts off of that are NLA or expensive otherwise. I will note that at least in my area, there seem to be many more of the vortec trucks in the yards these days than TBIs. Not sure if this is the same everywhere.
Yes I've noticed that in Houston, Texas area too. I think part of it is just attrition; the older they are, there's not gonna be as many of them left.
 
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