School me on big trucks - 89 GMC 6000

[Bagd72Chevy]

I've been looking for a big truck for some time now and found out a friend has an 89 GMC 6000 ex U-Haul truck I could get for an extremely reasonable price. I have not seen it in person yet.

Things I know:

It has a 366 V8, manual trans, its long. Hasn't run in a while, someone said the fuel pump was changed last but they thought it might not have been the right one.

Are these trucks carbureted?
Is it a 5 speed or 5+2 or what??
I see in pics it has an air compressor, does it have air brakes?
Can these trucks be lowered any?
Is the cab different from a pickup?

Ideally I would like to get it running and drive it to my house but I'll tow it if I need to. Not sure if it's height would be too high on my gooseneck. Its not that far from me if I could get the brakes working and just pull it home with my duramax.


My plans:

I have an LBZ Duramax donor with allison and transfer case. I would like to swap it, make it a crewcab, add a ramp bed or roll back and use it to haul my hotrods/C10's. Maybe make it 4wd if I could keep it lower like a newer kodiak/topkick.

[GM72K10]

We used to have an 89 GMC 6000 with Uhaul specs, 366 big block with a regular old 4 speed. The 24 footers supposedly had 5 speeds ( I think) Don't think any had 2 speed rears. Ours had Vacuum assisted brakes. Bad on gas but served its purpose. Plenty of power for plowing too.

[sweetk30]

cab floor totally different than reg 10-30 cab floor.

if air compressor on motor then its prob air brakes . = cdl to most people to drive it . and as i am finding out had to find correct replacement engine for the trucks with factory air brakes and compressor .

carb NOT efi in that style yet.

2 speed rear hit or miss . have to just look for shifter or axle its self .

[KQQL IT]

Air compressor usually had air ride a Uhaul thing.

Being a U haul should be way under 26001 gvw and have hyd disc brakes.

[special-K]

Yeah, no air brakes on a U-Haul. I'm sure no 2spd rear either. These were built for the general populous, not CDL drivers. I'm surprised it's not an automatic. Probably a Clark 5spd. Is this the low profile? IIRC, those came out right about '89 and U-Haul was all over them. Maybe those were lighter than the 6000s

[C10 - C90 Bill]

I also questioned Air Brakes on a U-Haul. Also a Manual Trans in a truck that new, as well as the 2-Speed Rear.

But surprisingly, when I rented a Penske truck once, instead of a U-haul which I would usually use when moving household goods, it had a 2-Speed Rear.

Most people who rented trucks like that would be lucky if they had pick-up truck experience. Half of them probably wondered what the heck that Red Button was for, lol.

[GM72K10]

I remember driving across Texas in September in the 80s in a Uhaul F600 with a governor and a straight 4 speed. What speed! What fun!

[Bagd72Chevy]

Thanks guys, I wasn't sure on alot of this. All the big trucks I've driven were auto's, some had air brakes. The GVW on this one is 17999. Here are some pictures the owner sent me, might make some sense to you guys.











In this last picture I can see the juice brakes and what I think is an air compressor on the engine??

[Bagd72Chevy]

This is my donor:

[sweetk30]

was that truck sitting in the swap water ? ? ? wow she is bad looking . . . i would crawl all over/under that thing before purchase . it might be solid rust on everything .

[C10 - C90 Bill]

Yeah, that's an Air Compressor alright, but I would say it would be more for the Air Ride as KQQL IT has mentioned.

It sure is in a damp place. I would also be concerned about rust. Not really sure I would want to crawl under it though, lol. Could be snakes or ??

[Bagd72Chevy]

Lol, everything is damp down here. I figured for a few hundos I cant go wrong!

You guys would be surprised how bad a vehicle will look just sitting outside for a few years. He lives over by some of the plants and the air is dirty. It was running and parked in its current spot in 2012. He went to move it a few months later and it wouldn't make enough power to go around the block. He is an old hot rodder/ret. engine machinist/now manager at Oreilly's so I'll give him some credit on the engine diagnosis. It is in his back yard, in a neighborhood although the pics make it look like it is sitting in the woods.

[Bagd72Chevy]

Went and messed with the truck some. Put a battery in it with 950 cca. Engine seems to be stuck. Going to go back Thursday and try to break it free and see if it will fire up on starting fluid.

Things I learned:

It has electric hydroboost and has airride. If I put air into the shrader valve by the compressor will that lift it up? The interior is super clean. 5 speed trans, single speed rear end. It seems to be pretty low, and its riding on 19.5's, Hub Pilot wheels. Its in pretty good shape, I would love to get it running witht he 366.

[sweetk30]

starter fluid is like meth for humans to a engine .

use spray bottle with gas in it or good brake cleaner thats NOT the safety kind no flamible. i have good luck with autozone brand brake cleaner .

i had a nice snowmobile one time . used starter fluid on it 1 time on a real cold day . after that it always wanted it some even 50-60* days . . . never again will i use it unless i know the motor has already had some before i ever got to it .

watch the suspension bags . full air up after sitting so long could be dry rotted .

the brakes are electric if there is no engine running . its the safety for the system . big trucks got this .

and the 19.5 low pro's are for the highway . its prob got o.k. gears in the rear but no real work gear .

if it goes for parts and not fixable i need some inside cab parts .

[Bagd72Chevy]

So we went and messed with it some more. New battery and electrical system seems to work. Truck came from Arizona/SoCal area by the maintenance log I found. Engine was replaced in 1998 and has ~30k miles since. The bad is the engine is locked up. It tries to turn over but I have a feeling it has some rust in the bores. Im going to pull the plugs and oil up the cylinders to see if it might break free. It seems like it wants to. I would love to get it running as is we can. Also putting air in that shrader valve does put air in the tank and pick up the rear of the truck. I noticed the compressor does not have a clutch on it??

[sweetk30]

Originally Posted by Bagd72Chevy

So we went and messed with it some more. New battery and electrical system seems to work. Truck came from Arizona/SoCal area by the maintenance log I found. Engine was replaced in 1998 and has ~30k miles since. The bad is the engine is locked up. It tries to turn over but I have a feeling it has some rust in the bores. Im going to pull the plugs and oil up the cylinders to see if it might break free. It seems like it wants to. I would love to get it running as is we can. Also putting air in that shrader valve does put air in the tank and pick up the rear of the truck. I noticed the compressor does not have a clutch on it??

air brake or suspension compressors in this use are full time run units . they have a bypass built in when psi is reached so they dont over pump .

[Bagd72Chevy]

Originally Posted by sweetk30

air brake or suspension compressors in this use are full time run units . they have a bypass built in when psi is reached so they dont over pump .

Makes sense. Still waiting on the current owner to get his stuff moved out of the box and then I'll haul it home.

[nuke1]

Sweet looking build!!! I finally got my Unicorn. A 72 c-50. Keelp us informed

[Bagd72Chevy]

Only been 5 years, but I got diagnosed with Leukemia. Doing better but I'm still waiting for the current owner to get his stuff moved out the box. Need to figure out the title situation. But I have acquired an AATAC rollback bed for it and a 5.9 cummins/5 speed combo to swap to. Looking forward to working on this thing when the weather cools off. Too hot right now.

[jumpsoffrock]

Originally Posted by Bagd72Chevy

Only been 5 years, but I got diagnosed with Leukemia. Doing better but I'm still waiting for the current owner to get his stuff moved out the box. Need to figure out the title situation. But I have acquired an AATAC rollback bed for it and a 5.9 cummins/5 speed combo to swap to. Looking forward to working on this thing when the weather cools off. Too hot right now.

Hard to hear about the cancer, glad you're doing better.
I thought you'd at least have had it drug outta the "woods" by now though lol

Good luck with all the work ahead.

[Bagd72Chevy]

Go it home finally!! Pulled pretty good on the towbar. Moved it just about a mile.

[Bagd72Chevy]

It was getting dark but my son and I went ahead and pressure washed the cab/hood some. Going to keep after it and get the engine compartment cleaned and ready to pull the drivetrain. I took some measurements and will have to move the rear axle back 18" right now if I follow through with a crewcab. will see how it goes.

[Lost in the 60's]

You should be able to sell that box to someone as a storage shed, unless you plan to keep it.
What did you do the LBZ donor ?

[Bagd72Chevy]

Originally Posted by Lost in the 60's

You should be able to sell that box to someone as a storage shed, unless you plan to keep it.
What did you do the LBZ donor ?

Took it apart. I have the LBZ/Allison sitting on a pallet in the shop. I modified the harness and reflashed it so it will run off a jerry can of fuel standalone. I've changed directions and going to put a cummins in this truck with a 5 speed/PTO trans to run a wrecker bed I picked up. The LBZ is going in an 88 squarebody dually.

[fluffyfreak]

any updates? ive beenwanting a big truck for awhile now! also, /// = Relaxed?