88 GMC Driver / Project

[Spray-Bomb]

Next on the agenda is a 6.2 diesel and NV-3500 trans

I've had the trans sitting around the shop for quite a few years, but I recently got the engine from my uncle (had to make him a trailer out of the bed)

Had to un-stick the fuel shutoff in the IP and buy 5 new glow plugs to get it running, going to be buying the other 3 before it goes in and it's also getting some upgrades from 6.5s: serpentine belt, starter, drivers side exh. manifold (for frame clearance) and upgrading the coolant cross over / T-stat housing to a 94 6.5 till I can get my hands on the 96 and later dual stat setup

I have a 93 6.5 truck for parts, so wiring harness, oil cooler, and hydro boost stuff is coming from it

[Spray-Bomb]

Got it running today, has been sitting dormant for 20 years and had a lil air in the lines, but it's getting better

http://youtu.be/NRzewDEQs3g

Also tested for hot start issues and it passed with flying colors, you look at it wrong and it'll fire up

http://youtu.be/UQHAI_qaY5Y

Stay tuned for my high MPG daily diesel

[Spray-Bomb]

And since some of you may wonder what's on the inside of the cab, here is the box I built for my 15" sub
I need to take some more pics, but I refrain as the inside just isn't very nice lol
When I swap to the 5-speed Ima have to build a new console to clear the shifter as the one I built for it like it is runs all the way to the dash








When I build the new console I will also fiberglass the box and wrap it in suede

[Ron 586]

You're making headway. It won't be long until you'll need to give it a little roadtrip and come up and pay us a visit.

[Spray-Bomb]

I'm hoping to be doing quite a bit of road tripping in it once I get it on the road with the diesel and all the bugs worked out

I'm shooting for the high 20s in MPG

[rusty76]

Neat truck man.!

[Spray-Bomb]

Thanks

[woodridge]

Neat Project young man, I like it.

[Spray-Bomb]

Thanks bud

I still love my old 67s but man this thing has me spoiled with heat N air and power locks N windows
My dad always told me one day I'd want those things...

[chevyboy73]

that rear window is unique! i really like the work so far!

[Hubscrub]

that's using your imagination, that's a cool build

[Hankster]

Anymore on this thing?

[Spray-Bomb]

Well I'm currently underway with the swap, I have hit a few snags here and there delaying the process but nothing too major

I picked up a 91 6.2 that came out of a service truck from a school, can't remember exactly but it has somewhere around 150k

I decided to get it running and see how I felt about it to decide if I wanted to use it instead of the 83, it started and ran just fine, so I decided to go with the 91 because of the 1-piece rear seal and was being driven less than 2 years ago instead of the 83 which has been sitting for 10-20 years (even tho I think the 83 runs minorly better) do to the fact that I don't really feel like putting all new seals and whatnot in either engine at the moment

So shortly after I bought the 91 engine, I posted the 350/700r4 combo for sale and sold it 3 days later, got some money and pulled it out that day



Made a list and ordered goodies for the swap



Dug out my two 5-speed transmissions only to find that one was sure enough bad, the other didn't feel that great, and that there were pre NV-3500 trannys, so the hunt was on for a NV-3500.... No real luck with that, so I had bought a NV-4500 a while back just for giggles, and even tho it's a lot bigger heavier and all that than I really wanted, it's what I had, so off to the driveshaft shop to get a re-modified shaft made (remodify: to modify something after it's been modified before, or if you are the guy I learned the word from, it doesn't even have to be modified before modification begins)

So with my super expensive remodified drive shaft (just had it modded when I lowered the truck) a big ol NV4500 trans, a 91 6.2 and some goodies from RockAuto and other places, I began the task of putting this behemoth together





In a stupid act of idk what several years back we left the hood off of my diesel parts truck and the sun decided to munch on the wiring harness and throttle cable I needed, and speaking of wiring harnesses the one that came with my 91 engine was for an auto trans and had been cut right at the firewall bulkhead on the pass side

So with 2 messed up engine harnesses I started the task of building one that would hopefully work (I say that knowing quite a bit about wiring, so you can tell this is a mess)
Just like every other manufacturer out there, GM decided that different years would get different wire routing, some different colors, and my favorite different wire locations in connectors





Found that GM also decided not to install the upper clutch pedal mount in automatic trucks, so I had a few options, remove dash and go drill the spot welds and remove the mount from a parts truck, then do the same to mine but weld it in instead
Drill holes and install nutserts / nut rivets
Or get some big self tapping screws and zip that thing in good.... I went with this option for ease, even tho I'd much rather have the factory mount, I really am not wanting to pull my dash yet

[Spray-Bomb]

I swapped from vacuum to hydro-boost and at the same time did away with the RWAL system and installed a Wilwood adjustable proportioning valve




I like the fact that the 83 had 2 spin on fuel filters instead of the crappy square box filter or the 6.5TD fuel manager drop in style on the intake
As for me I think having filters in awkward and hard to reach places is just dumb, so I made a bracket and relocated the secondary filter from the 83 to the firewall instead of the intake, the primary / water separator will be in the bed (no more fuel baths when changing filters !!!!)






I will also be modifying / bending up some new fuel lines and run them down the passenger side frame rail instead of the drivers side like factory

I have moved my fuel tank from under the bed to in the bed, this is ugly and I don't like it, but it's only temporary till I get a big aluminum semi tank

And the money shot

[Hankster]

Sweet! Glad to hear about some progress on the truck.

[Dub_X]

Glad to see progress. And on that note. I FEEL YOUR PAIN WITH WIRING!
GM books say 88-94 is the same harness. My ass. 88 and 89 are the same. Everything else, not so much. I found that out the extremely hard way doing my 2WD to 4WD conversion using different parts.

[Spray-Bomb]

Well here's another update for those who follow this thread

I had it real close to driving, but needed something to drive since I hadn't had anything to drive for about 4 or more months, so I took a break from the GMC and put my Honda back together, long story short I'm selling the Honda and have gotten my truck back on the road, it still needs work, but is getting me from place to place

I'll have to take some more recent pics, but here are some that will update yall a lil

Ran all new fuel lines and mounted a FASS fuel pressure regulator to cut the pressure down from around 20 psi from the stock TBI in tank pump down to about 4-6 psi that the DB-2 Injection pump needs







Swapped my plastic clutch master and slave for some 90 1ton cast iron ones, and built a Stainless braided Teflon lined hose with Banjo fittings (note, this works but you must you the longer rod from the previous slave cylinder and it pushed my clutch pedal way up, so I'll be having to cut it down)


And I got my exhaust installed, true dual 3" with single chamber CherryBomb Extremes

[Spray-Bomb]

The diesel and heavy trans lowered the front around an inch, which was nice since I won't have to install drop springs to make it sit level anymore



Currently some of my more major issues are: #1 my trans is a major POS, it grinds in every gear but 5th and 3rd will pop out in decel, plus it rattles like a snake pit
I'm currently double clutching at just the right speed to keep it from grinding most of the time, but downshifting is a guaranteed grind
So I either need another trans or to rebuild one, but since I have the early NV-4500 and I feel the first few gears really are a lil deep, I'm thinking about going with the 96 plus, but that will require modifications to the hydraulics, since they have hydraulic throwout bearings

Another issue is that my speedometer sits at 25 mph no matter what, key on, key off, driving, sitting still, it don't matter
My feeling is that it's not getting switched power, so Ima have to track down that wiring issue
And while I'm doing that, my glow plug light and check engine light don't come on either, so I'm going to try and fix those as well, just to make it nicer

[bufmatmuslepants]

Awesome and very unique build, I really like the style you are going for. Can I ask who shot the truck up with the 12 gage? That takes alot of rage to blow a truck up like that...

[Spray-Bomb]

Not really sure who did it, but I reckon it was the ex...

[Hankster]

Good to hear an update!

[Palf70Step]

Glad to see it cruising around. Looking forward to more updates.

[Spray-Bomb]

Lil update

Replaced the crappy trans with a 96+ trans, had to use a 96+ pressure plate, disc and flywheel to do it, as the earlier external slave transmissions have a different finger height on the pressure plate, along with a different ID on the disc and flywheel

The later flywheel is cut out more in the center and the disc is narrower if that makes sense, has a lil more grip since there is less surface area and therefore more pressure

Also went ahead and used a full hydraulic setup from a 96+, I do remember something different about the clutch master tho, seems that I had to use an earlier one because it has the 2 bolt flange and later ones have a square hole they clip into or something.... Been a while since I swapped it

If you're running an NV-4500, do yourself a favor and make sure you get the proper fluid (if you're still running carbon synchros)
GM part number 12346191
Mopar part number (one of these is current other is outdated) 4637579 or 4874459

Castrol made the fluid for GM and Mopar, and it used to be available in stores, but it has been discontinued and is only available at the dealers, and I'm not even sure they still make it for them, so it's hard to come by
Castrol Syntorque Synthetic 75w-90

The 96+ trans is better, but for a 1/2 ton with 3:42 gears it's still a bit deep, I only use granny when needed, but even taking off in second you only get up to about 10-15 without winding it up, but taking off in 3rd bogs it too hard

During the early part of 2015 Van Texas had a tornado, and while helping out I caught something in a tire, had a blow out and wound up getting a new pair of rear tires, since I was getting new tires I powdercoated some 78 Chevy wheels and put some 67 GMC dog dishes on them, when I get new tires for the front, I'll do the other wheels and have a full set of 5-lug 15s with 67 dog dishes

On the 4th of July 2015 I hit a deer and broke the grille, parking lights, and condenser, replaced the grille, but have yet to fix the other stuff

Other than those highlights it's just been regular maintenance and driving

I have a set of poly bushings for the whole truck and new ball joints to go in soon
I've already installed the poly cab mounts and they will be coming off and getting sold, they make the truck ride like a brick compared to a caddilac with the factory rubber mounts

Things to come will be: adding a second alternator (for the demands of my stereo) possibly adding a turbo (already have most of the stuff), paint, interior, putting a fuel cell under the bed, and doing a trailing arm conversion to the rear along with bags in the back instead of coil springs

[Spray-Bomb]

Couple other things I noticed I haven't updated y'all on

I went back with the 4 headlights instead of the crappy yellowed composite headlights, the housings are from LMC, they're very nice with aluminum reflectors and crystal clear glass lenses, I'm running DDM Tunings Ultra HID setups in both high and low, the only 2 problems are: the ultra bulbs are too long for the low beam housings due to the shields, so till I separate the housings and mod the shields, (I'm running regular HID bulbs in the lows for now) and it needs to be wired for high 4 so you don't go dark between high and low

I won't ever use slim ballast HID sets again after having these Ultras, much much much better with these (35w btw)

I also modified a pair of wiper arms to accept longer blade, 22" as I recall vs the stock 16"
With such long blades I get a full sweep of the windshield with nearly no triangle in the middle, it's great

[Palf70Step]

Glad to a see your still at it on the trucks and that this one is still cruising. Good info on the tranny stuff.