GMT400 suburban questions

Martinjmpr

Wiffleball Batter
Found a 6.0l 2500 suburban, he's asking 6500$ and its 140k - thats lower than most 1500s I've seen. The only thing I'm worried about with that is the MPG - most people don't ever even reach 15 MPG with the 6.0, and the 5.3 Is supposed to get closer to 18 mpg... I wonder if it'd be worth it to get the 1500 model and then swap in the SF 14 bolt, and another transmission... the 4l80e would be mostly bolt-in but after that would I be getting similar mileage to the 2500? hmmm...maybe if I can find a good deal on a 02-03 2500 I could plan a nv4500/zf6 swap in the future... I bet that'd net some MPG

That sounds like spending a hundred dollars in order to save a few pennies
 

MTCK

Observer
For the mission you're talking about a 1500 might work fine. That's the only way you're going to get the better MPG. I also think buying a 1500 for the smaller engine and doing all those mods is throwing good money after bad. Also if you are looking 3/4 ton most folks don't do any better with a 6.0 than an 8.1, plus I think you get a 10.5" rear vs 9.5" that way. Interior looks nice on that rig but the fact that it's started rusting out (they don't stop once they start) would be a deal breaker for me. I'd look south and figure out if you need an HD or not. Good luck.
 

Martinjmpr

Wiffleball Batter
That's not a bad price for a 2500 but I'd be leery of the rust. Mine has some surface rust on the frame (courtesy of 8 years in WI) but apart from a little on the bottom of the doors it is free from any major body rust. Here in CO it's dry enough that rust isn't generally a major issue on anything less than 20 years old. Up in MN I think rust is a much more serious issue and if that's where you live it's only going to get worse.
 

rayra

Expedition Leader
quarter million miles on our 5.3s, I've never averaged more than high 15s. You'd have to be driving AT the speed limit and pure highway to get anything near 18.


You have to put those MPG differences into a proper context. Don't put too much weight on the advertised / claimed MPG figures, except in general terms and by class of vehicle and engine. It's more dependent on your individual driving habits / use than anything else. And bottom line, you're talking about a giant bus. MPG concerns shouldn't be a primary concern or even in the top 5 concerns, especially if you are purchasing a used one. If MPG is, you should probably choose a lesser vehicle.

national average vehicle mileage is 15,000/yr. A 1mpg difference on that is 1000mi, or roughly 67gals. ~$200-250 per year. per 1mpg. So at max it's a $750/yr difference if you drive the Sub full time.
In my case, I'm only driving the Sub ~6k mi/yr. For me a 1mpg difference is <$100, on the most expensive gas in the nation.
So if a few hundred dollars a year is enough to put a substantial dent in your budget or trigger major alterations in your vehicle use, then the Suburban is probably not for you. And if the Sub is an 'extra' vehicle, then the MPG really shouldn't matter much.
 

peasy

New member
IDK if it's the dry-ness in CO- you guys don't salt the roads AFAIK and that is probably the closest state to me where u can get nice non-rusty trucks. Everything up here is rusty, but suburbans are generally owned by wealthy people with garages that can afford to wash the salt off their car throughout the winter so that helps. I don't think that a trip out of state to buy a car is really an option for me, as much as I'd like a rust free truck..thats a lot of extra dough.

Had a 92 chevy k3500 and I banged a 2 square foot pile of rust scales off the frame after I bought it :Wow1:



....I think I need to find a good deal on a -02/03 2500 until I can afford to drive it south and tow back a rust-free body donor.
 
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peasy

New member
yeah I guess if I'm planning rust free body swap in a few years down the road I shouldn't completely rule out the 8.1... I'd rather have the couple more MPG of the 6.0 cuz I really don't need the big block but they are more plentiful when it comes to the 3/4 ton models


...them goofy *** wheels tho - whats wrong with steelies?!? I know the new suburban wheels can go from 300-600$ each...we had a lot of them stolen from the GMC dealership I worked at; nobody gona steal mine when I put stock steels on
 

Martinjmpr

Wiffleball Batter
yeah I guess if I'm planning rust free body swap in a few years down the road I shouldn't completely rule out the 8.1... I'd rather have the couple more MPG of the 6.0 cuz I really don't need the big block but they are more plentiful when it comes to the 3/4 ton models


...them goofy *** wheels tho - whats wrong with steelies?!? I know the new suburban wheels can go from 300-600$ each...we had a lot of them stolen from the GMC dealership I worked at; nobody gona steal mine when I put stock steels on
.
Alloys are lighter. I picked up a set of 2000-2003 Suburban/Tahoe 16" alloys for $140 on CL. Not too pretty but running 16's vs. 17's will save me around $200 total for a tire with the same width and diameter. ;)
 

peasy

New member
I was under the impression you had to run 17s to clear the gmt800 brakes??? am i wrong, or did you shave calipers? I'd much rather have 16" steels like I had on my 1 ton for 50 a pop from partsgeek.
 
I was under the impression you had to run 17s to clear the gmt800 brakes??? am i wrong, or did you shave calipers? I'd much rather have 16" steels like I had on my 1 ton for 50 a pop from partsgeek.
My 02 2500hd has stock 16s

Sent from my Vortec-powered Droid Turbo using Tapatalk
 

rayra

Expedition Leader
I was under the impression you had to run 17s to clear the gmt800 brakes??? am i wrong, or did you shave calipers? I'd much rather have 16" steels like I had on my 1 ton for 50 a pop from partsgeek.
1500 LS and LT GMT800s have 16" wheels, the Z71s have 17. All three models have 13"/330mm rear rotors and 12" front. GM made several such incremental changes in wheel sizes over the trims / generations, without strict / corresponding enlargement of wheels / brakes.
 

peasy

New member
My 02 2500hd has stock 16s

Sent from my Vortec-powered Droid Turbo using Tapatalk

1500 LS and LT GMT800s have 16" wheels, the Z71s have 17. All three models have 13"/330mm rear rotors and 12" front. GM made several such incremental changes in wheel sizes over the trims / generations, without strict / corresponding enlargement of wheels / brakes.

awesome that's good to hear! Guess I'll be buying some wheels as well when I get a set of ATs
 

Martinjmpr

Wiffleball Batter
I was under the impression you had to run 17s to clear the gmt800 brakes??? am i wrong, or did you shave calipers? I'd much rather have 16" steels like I had on my 1 ton for 50 a pop from partsgeek.
.
When I pulled my spare I noticed that it was a 16.
 

Martinjmpr

Wiffleball Batter
1500 LS and LT GMT800s have 16" wheels, the Z71s have 17. All three models have 13"/330mm rear rotors and 12" front. GM made several such incremental changes in wheel sizes over the trims / generations, without strict / corresponding enlargement of wheels / brakes.
.
I'm guessing the 16's only went on the earlier (2000 - 2003) GMT-800 Suburbans and Tahoes. FWIW my '04 LT has 17's however they're not the same 17's that are on the Z71. I call the Z71 wheels "snowflakes" because of the way they look. Mine are a 5-spoke pattern in a "star" shape. I don't really like them but they'll do until I can get a lift and then put some decent tires on.
 

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