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K5 Cummins/1 ton axles build

KB6Chris

Well-known member
Joined
Feb 20, 2022
Member Number
4861
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IL
I was always a big fan of build threads and having done a couple "builds" in the past with no threads I thought might as well do one for this.

Fair warning. I like to talk and story tell so this might be long winded

Starting out I bought a 1984 M1009 which is the military version of Chevy's K5 Blazer. All M1009 came with the 6.2 Diesel, TH400, 10 bolt front/rear with the G80 in the back and 3.08 gears. Truck had been stored inside and only had one tank of fuel ran through it in the last 7-8 years.

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Pretty well kept rig and I used it as my daily for almost a year and really started to enjoy the utility of it. Being able to tow my SXS, carry 4 people and lots of stuff comfortably, 4x4, fuel sipping engine, 2 door classic look.

But, after putting close to 10k miles on it some age related issues started to show. The fuel system had many problems (probably due to running 7 year old diesel fuel) being a sticky governor and hard cold starts even with fresh glow plug system. The trans would not shift when cold. And a ball joint started going out.

Even though these would be pretty easy, cheap, and simple fixes I found a screaming deal on a wrecked 12 valve/nv4500/4wd Dodge soon after these problems arose.

It was as if it was meant to be.

Here is/was the plan

Past 3/4 years I've been wanting to do some road tripping/camping out west as I've never been West of the Mississippi and I wanted to build a rig to do it.

So I had a Chevy Kingpin 60 laying around I had bought for another truck, the 12v Cummins, NV4500 and the Dana 80 SRW axle out of the wrecked Dodge. Although I wanted this to be off-road capable I knew I was going to be just driving it up and down the road 90% of the time so I wanted to gear it more friendly towards the highway and daily driving. The rear axle was already 3.55 gears so I ordered 3.55 gears for the front and accidently ordered ARB air lockers for both axles. Oops :laughing:

Before I ripped the Blazer apart I started getting the major components together so as to try and keep the vehicle downtime to a minimum.

The engine and trans were operating well before I pulled them so I opted for just replacing the gaskets and seals and things like water pump etc..

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I completely rebuilt the Dana 60 though with new bearings, seals, kingpins, brakes, locker, gears. I see why people say that buying the axle is the cheapest part.

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In the meantime the Blazer started to develop a bad fuel leak somewhere and when I drove into the shop to try and find it I decided now would be a good time to start tearing it apart. I pulled off the hood, grill, rad and doing everything else that's necessary to do the swap.

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I got the drivetrain pulled and ordered the mounts and crossmember off of Agan Fab to hopefully speed up the process.

The kit came in and I welded it up, but the bushings for the engine mounts were the wrong size and had to be cut down. I also had to modify the frame plates to get more clearance under the engine. I talked to Ryan at Agan Fab and was very helpful with making the adjustments to his kit.

I also had to fab up the transmission crossmember. I used the factory 5 speed mount and cut a hole/notch in the blazer crossmember and put a plate in and I was able to just move the crossmember rearward a couple inches and drill a couple holes and bolt it back up. I had to put a piece on the crossmember to widen it out just a bit to reach the frame though.
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In between doing all of that I freshened up the Dana 80 with new seals, brakes, and the locker.


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Once the axles were done I pulled a 4 inch lift out of a parts blazer I had acquired and rolled the axles under and put the lift on which is springs in the front and just a block in the back. I had thought about doing a shackle drop but decided I'd try the block first. Soon after I found a guy selling some fairly new 315/75r16 Cooper's on like new American Racing wheel 16x10's and bought those and put them on

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The transfer case was going to be a little tricky as the Dodge had a drivers drop T-case and I needed a passenger drop. A lot of guys use the NP-205. Doing that entails either locating one off of a 1st gen dodge and around here guys are asking an arm and a leg for, Or finding the np241c passenger drop which is also hard to find/expensive.

The other option was swapping the NV4500 mainshaft to 32 spline and rear housing to be able to use my NP208 :shaking:

Instead I lucked out and found a guy selling a NP241D out of a ramcharger for dirt cheap. I soon found out why.

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So I thought something was wrong with using one of these cause nobody talks about using one in the squarebody cummins swap pages but I couldn't figure out why not.
So these NP241D usually come with the 23 spline found in most Dodge automatics and a fixed rear yoke. While no one lists a 29 spline shaft on the internet anywhere, someone mentions I call Midwesttrans and talk to them. I call them up and tell them what I was doing and they knew exactly what I needed. A new input shaft arrived a couple days later and I start tearing this T-case apart.

Now before I tore it apart it was evident that someone had been in it before because none of the bolts were tight but I could still spin the shafts and it shifted both range and mode fine so I had assumed it was all good.

First thing I find is the oil pump is junk, as well as no pickup tube. I continue on and pull the rest of it apart. Everything else seems good so I continue with the input shaft install and all new seals. I rob the pump out of another NP241 and fab up a pickup tube and start putting it back together. All goes well until I try tightening the bolts up. Its like there's an 1/8th inch gap on the right hand side and when I tighten it up the front output locks up.

Long story short after taking it apart and back together half a dozen times I discover that someone had put the wrong front output shaft in it. So I order the correct one off of ebay and after I slap it in there and begin to put it back together it bolts up just like it should. The best part was that it slid right on the back of the transmission with no adapter or clocking ring and the front driveshaft will still clear the crossmember

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Now here is where I'm at a year to the day after driving it in the shop, and I told the g/f I was gonna have it done by last Christmas :shaking: Well that came and went so now the new deadline is this Christmas lol.

Still have to do steering, cooling, clutch hydro's, wiring, new brake lines, driveshafts, t-case linkage, fuel, air, and everything else. But now I feel like the end is in sight lol
 
Should be a nice usable build man, I like it. I must be about the only person that swaps 6.2's into trucks instead of out of them though they are getting harder to find for $50-100 so that might change lol.
 
Should be a nice usable build man, I like it. I must be about the only person that swaps 6.2's into trucks instead of out of them though they are getting harder to find for $50-100 so that might change lol.
I will say I have had good experience with 6.2 diesels in general despite their bad reputation. The one I pulled out of the K5 I plan to get the inj. pump fixed and stick in K30 I have with a blown up 6.2
Sub’d

You did address the killer down pin?
Yes, every 12v I get I pull the timing cover and put a tab over the dowel pin.
 
To late to matter but ord sells short 29spl female 205 inputs so you can dirrectly mate a gm or ford 205 with no adapters.
 
To late to matter but ord sells short 29spl female 205 inputs so you can dirrectly mate a gm or ford 205 with no adapters.
Or you can use factory parts. I have them here, a 29 spline male output Dodge 205, with the coupler and adapter.
 
To late to matter but ord sells short 29spl female 205 inputs so you can dirrectly mate a gm or ford 205 with no adapters.
Would the bolt pattern work to attach the 205 to the dodge nv4500 or would i have to change the tailhousing on the trans or the front of the 205?
 
Or you can use factory parts. I have them here, a 29 spline male output Dodge 205, with the coupler and adapter.
I wouldve been fine using a 29 spline 205 if I couldve found one as cheap as I found this 241. Most guys around me are asking close to $1000 for one and i have less than 400 in this one after it was all said and done.

Although I think I will like the 2.72:1 low range of the 241 vs the 1.96 of the 205
 
Ford and dodge use the same pattern clocking.

To dirrect mate a 203/205 you will have to clearance the input seal retainer bolt heads in the back of the 4500 housing and notch the ring of the housing for the shifter rail and idler shaft washer.

And get a castiron tail is youre gona run a heavy/iron tcase

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Little bit more progress on the K5

Got the fuel lines hooked up just cutting the stock steel fuel lines just over the axle sliding hoses onto them and going up the driver side frame-rail and hooking up the the lift pump and return off the injection pump.

Also got the brake proportioning valve relocated as well as all new brake lines ran. I really like the Ni-Cop lines for bending and flaring but its damn hard to keep them straight and pretty.

I resealed the brake booster as it had been seeping into the driverside floorboard for a few months before I rolled it into the shop. The two little o-ring/wiper seals on the rod side are a joke to replace. Only solution I found is to cut the rod that goes to the pedal to slide the new seals on and re-weld the rod end back on as the rod is crimped onto the shaft in the brake booster and not removable.

I also bought a new master cylinder for a K30 thinking the larger brakes needed a larger master cylinder. I read different experiences where some people said the K5 MC would work with one ton axles and some said it wouldn't. Who knows?

I was back and forth on doing crossover steering or not (pun intended) and decided to just go ahead with it instead of doing push pull. So I ordered a 2wd steering gear from Redhead and they said it was fine if I sent my 4wd one back as the core. I plan on ordering the Jeep XJ steering shaft to replace the factory one with the rag joints.

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While I had it off I was looking at reinforcing the steering box frame area. Mine isn't cracked yet but I see ORD has options with using the weld on plates or the bolt on brace. Looking at bolt on brace I think I would run into clearance issues with the engine so I think I'll have to settle for the weld on plates. My question is are the plates good enough or do I need the triangulation that the brace provides. Granted I don't wanna go with any larger of a tire than the 35's so I might be okay but thought I'd ask the experts here
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Also that parts blazer I took the lift off of was a 1988 with the hydraulic clutch so I went and robbed the pedals out of it to put in this one so I have my hydraulic clutch.

Little side note, now that I've been working on this thing a year I've been getting withdrawals from not being able to drive it so I bought another one off of marketplace. Guy delivered it from 6 hours away and I'm split between wishing I just gave him fuel money to take it back home with him or not.

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Only rust is in the rockers which were covered up with tape and I didn't notice till I put it in the shop and looked it over after he left. A small spot on the tailgate and a small spot on the lower B pillar. All and all pretty good shape compared to the rust buckets floating around Illinois for the same price. But theres a twisted off bolt on the steering pump bracket causing a belt alignment issue and a pretty nasty sound on the lefthand side of the engine. I bought it hoping to be able to drive it around till I got this one finished but now it looks like its going to turn into the next project...

So I'm just gonna have to work twice as hard to get the first one done so I can fix this financial mistake later. I'm thinking I should find some medicine for the truck project attention deficit disorder before I get to much stuff in the shop I can't walk around anymore lol
 
Why not just replace the engine in the new one with junkyard parts? Carb 350's can't be that expensive since everyone is into ls's like a hillbilly into his sister. Quick cheap fix and you can drive it inside a weekend...
 
Weld on brace for steering is a must. Frame will crack with stock tires and cross over.
 
What about a borgeson steering shaft? No rag joint, no cutting/welding and bolts in. Also, I would do the weld plates
 
Why not just replace the engine in the new one with junkyard parts? Carb 350's can't be that expensive since everyone is into ls's like a hillbilly into his sister. Quick cheap fix and you can drive it inside a weekend...
I thought about doing that except with the 6.2 I took out of the Cummins blazer. It had some issues with the fuel system but it was in much better running shape in the one that came in this. I also have a supposedly good 6.5 Turbo diesel in a parts truck out back that I thought about stabbing in but right now I think the quickest and easiest would be the best bet.
 
Either way i don't think it would behoove you to put it on the back burner... might as well put the longer term project on the bb for a bit and fix the new one.
 
I have an 80's k5 frame chunk that's broken to rat-shit in the steering box area with a crappy doubler plate goober-welded over top. I don't know the history, but it failed as miserably as the fix looks :laughing:

The 8600+ gvwr trucks have thicker steel.

I actually like push-pull steering under a Cummins when staying with low-travel leaf springs. Another route to take for steering is the early dodge reverse rotation box which moves the pitman like a pendelum instead; doesn't stress the frame the same.
 
cross over steering was one of the absolute best things i did to my 1st gen cummins, far superior steering
 
cross over steering was one of the absolute best things i did to my 1st gen cummins, far superior steering

Please explain... in the context of equal-length pitman arm, and only 2-3" of suspension travel.

I want to know because I'm sitting on nwf arms that I'm still not using on my 1stgen. :homer:
 
Please explain... in the context of equal-length pitman arm, and only 2-3" of suspension travel.

I want to know because I'm sitting on nwf arms that I'm still not using on my 1stgen. :homer:
Bump steer. Swapped to crossover on a 1st Gen Cummins Blazer on stock 52" springs and got a much better ride with the longer drag link and the Chevy D60 front.
 
Bump steer. Swapped to crossover on a 1st Gen Cummins Blazer on stock 52" springs and got a much better ride with the longer drag link and the Chevy D60 front.
at the time mine had a chevy d60 and 52" springs as well, now it has f550 super duty leafs up front

not sure cross over will fit on a stock 1st gen
 
No perceptible bumpsteer with my push-pull. I've got some beefy 2" leafs and another 1.5" in static lift. This truck needs to do chores more than flex, so it looks like I'll use the nwf arms on another project instead.

What's OP got for leafs? And clearance under the engine?
 
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