98 GMC 6BT Cummins and NV4500 build

At one time I had a 98 CC Chevy with a 6.5. Loved the truck, just hated the motor. I traded it off yrs ago. I got the itch to find another dually, but didn't have the funds to do such. Well, back around Feb I was on another forum and a member was in need of another SxS since his got totaled. I was looking to flip one I had picked up cheap, so I gave him a call. Somehow or another he told me he had a dually he wanted to sell. I became very interested. Long story short, I traded straight up for it. He brought it to me and so began a tear down.

What I started with:



Pretty decent truck. Wasnt exactly wanting a 4x4, but it'll do. Since it was 4wd, I was gonna go for the whole lifted, big front bumper and custom built flatbed look, but that all changed, which I'll explain later. The BB originally in it was knocking. And the original 4L80 had been swapped over to a NV4500. That was cool with me because I was planning on doing that anyways. I just like standards!

Tear down begins:



BB out. Already sold before it was on the floor.



Pile of parts:



Cummins out of donor. I actually owned it and drove it as a knock around truck for a couple of years. With over 400k mile, the suspension was slap wore out. Motor was still strong thou:



Test fitting. Close, but it'll work.





My mounts from Autoworld. I could have built some, but these took all the guesswork out. Very knowledgeable people.



Had to get a little creative with the trans. I learned all the differences about NV4500 based on yr model and if it was a GM or Dodge model. Mine was 95 GM model. I had to change the input shaft and bearing retainer to Dodge and redrill the 2 bottom mounting holes to fit the Dodge/Cummins bellhousing. Also had to machine my bearing retainer to fit the GM trans.



Engine and trans bolted together ready to stab:



I didn't really take many pics past this point, but here are a few. I ended up installing a 3" bodylift to make it easier for bellhousing clearance and was going for the whole lifted look. Move the trans crossmember back 3" and shortened the driveshaft also. Built my own exhaust using the donor Dodge downpipe. Nothing fancy. Motor is all stock.

Core support modified and I/C installed:



First start since in GMC. Click pic for a short video:



Pretty much finished with install and driveable. I love a Cummins!:





Aint looking too bad:



BUT....
Now with it running and driving, the 315 mudbrutes suck! Rough, noisy, and one must had a knot on it, because it shook horrible! I had a set of 245/75 practically brand new I decided to put on:



Much, much better. But now since I aint gonna do the whole lifted 4x4 thing, I've decided to pull the bodylift, the cow catcher bumper, and do a static drop. However low I can go just decranking the keys and pulling leafs, drop shackes is all I'm going. I know some people may say its stupid to lower a 4x4 and whatnot, but is easier and cheaper to do that then to find another 2wd and do it all over again. I would love to make it a 2wd, bag and bd it, but that's not gonna be anytime soon. Until then I'm just do the small stuff. Got all my gauges working except the tach. Be easy once I do it, lol. Gonna swap the gears over to 3.42's. The 4.10's are tach me out at a whole 77 mph. They gotta go! A/C is another future thing. Maybe some better looking wheels. Semis if I can find them on the cheap. I'm on a tight, tight budget. That's where I'm at now with it. Thanks for looking. More pics and write-ups coming as progress moves forward

sweet build.....my dually tops out at 77-78mph also so i feel your pain there lol

I put 3.42s in my truck and I love it. It helped out a ton.

Yeah, I wanted to find a 2wd, but I came across this one and it was a good deal. I'm still gonna static drop it however much I can without throwing the front off too bad. You know people gonna talk, but its my truck, I can do what the f*ck I want to it, lol. If I can find a 2wd chassic I'll swap it out. But you know how that goes....

your truck looks great. im luvin the cummins....I got to get me one.. there is no substitute...hahaha

Thanks. I found a 2wd 99 classic cab and chassis model here in town I gotta do some checking on. The cab is beat the hell and back, but I had the idea of just using the 2wd chassis and putting my cab and bed on it. But I dont know if everything will switch over and if the bed will fit without doing some mods. Gotta look into it.

You can just unbolt the 2wd front end and it should just bolt in to the frame? Then you wont have to swap out the whole frame.

good job on the motor swap...looks and sounds bad ass

I thought it would be that easy also, but then thought about how the coils would fit. 2wd has coil buckets, 4wd don't. If I was bagging it I could build bag mounts and use the 4wd frame, but this one is staying static dropped. Probably just gonna hold off on converting it and just do a mild drop for now.

Since I last visited I installed 3.42's. Man did it make a hell of a difference. I can actually drive it without it sounding like I'm gonna blow it up. Modified the firewall and removed the bodylift. Took the cowcatcher bumper off the front and put a regular chrome one. Other than that I just been driving it. Too much work converting to 2wd (I'm lazy) so I'm gonna just do a static drop low as I can without hurting the frontend too much. I drive it more than my new truck.