1985 W350 Crew 4x4 Shortbed Conversion

[James Ayres]

Time to start my build thread. I tend to be long-winded. If that's not your thing, sorry. But I'm posting this for my own documentation as much as for anyone else, so there's that. First though, thank you to the several people who have already done this type of conversion/restomod and had the inclination to also post build threads, tips and tricks, and other great information. I've been lurking on a LOT of those threads/posts to prepare myself for this one, and will continue to do so. Hopefully will be able to add my documented experience to the wealth of information about this kind of awesome adventure in time.


Background & Goals: So late July 2018 I picked up a 1989 W250 diesel. Prior to that I had zero knowledge about the 12v Cummins or any other diesel engine, really. But I jumped in head-first and, I think, got a little lucky along the way. I wanted a truck. I hadn't had a full size pickup in awhile, hadn't had 4wd in awhile, and I was beginning to miss it. After looking around, including noting the sticker price of new trucks, the legend of the 12v Cummins engine, the nostalgic styling of the trucks of the late 70's and 80's, the thought of building up my own became very enticing. I knew I wanted a truck that had enough room to comfortably hold my entire family because, after reading a bit on the Cummins, I knew I could get decent fuel mileage out of the thing and thus could make it a daily driver. I looked around for some mid- to late-70's Ford trucks, super cab, crew cab, whatever it took to get room in the back. Not finding what I wanted, I started to get stumped. Then a buddy advised to try and just find an old single-cab Dodge with the Cummins engine to use as the donor first, and worry about the swap later. So, I did.


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(Pic: Bringing My 12v Home)




Donor 1: The '89 diesel I acquired wasn't in the greatest condition. I negotiated a price based upon the fact that it was already 4wd and had a Cummins 12v inside that started right up and ran without issue. Blow-by was nonexistent. Other than that, I didn't know a thing about it except what the Seller told me - he had just gone through the rear axle for new bearings, seals, brake lines, etc., and I'd have to trailer the thing home because the front brakes weren't good. Full disclosure, I'm not a mechanic by any stretch of the imagination. My dad said he worked with his back so I could work with my brain. I've got an office job. But I'm a quick study and not afraid to dive in and learn things. I enjoy that process a lot, actually. This truck was purchased because I could drive it almost immediately, and it had the engine I wanted for my future swap. It wasn't until we were on the way home that I found TWO owner's manuals in the glove box. The first for a 1989 W100 (how the truck was actually titled) and the second for a 1990 Dodge diesel. This had been a swap. The seller didn't inform me of that and later I decided he probably didn't know. I had to gather more clues about the truck upon my own inspection and research.

 

[James Ayres]

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(That 12v Cummins Engine)

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(Timing Advanced on the VE Pump)

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(New Process 205 Transfer Case)

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(Transmission Pan - Yuk)




So getting the thing home I started looking at the totality of the truck. The 1990 Owners Manual indicated that the 12v was definitely from a 1990 Dodge, and the engine plate showed a manufacture date of 7/1989 which lined up. The dash must have come from the 1990 too, because the speedometer went to 100mph rather than just 85mph, a change that happened in 1990. The ODO didn't work but the seller told me it had broken not long ago and was estimated to be at 150,000 miles, showing 134k. The dash and HVAC were for an AC truck, and the 12v has an AC compressor on it. The radiator was new and has top driver's side output for an intercooled-style 12v, but the water neck on the engine is original and turned for a passenger's side rad output. There are 2 upper rad hoses clamped together to compensate. The VE pump appears to have been clocked forward 1/8" due to the little marks made on the back of the timing cover so I'm guessing the "free mods" have been done. Both front and rear axles had tags indicating 4.10 gears and they did check out as a Dana 60/70 combo. The transfer case leaks a little oil but otherwise did check out as a NP205. The transmission was a mystery. Being an auto trans at this point in time (1989-1990) it only made sense to be a 727. Buy why the heck would the axles be geared at 4.10 if that were the case, because anything other than the 3.07 D61/71 combo meant I'd be limited in top speed? There was no TPS on the engine, so maybe it was originally attached to a manual transmission? The axles were surely from the 1990 truck because they were definitely a D60/70 combo, heavy duty, which matched up for a Cummins truck but not for a gasser W100, which I think would have more than likely had a D44/60 combo. And I found a plate indicating that somewhere along the line this thing had a snow plow? Is that why the wiring seemed so sloppy, because it was removed? Is that why the transmission pan and crossmember look like they've been sprayed with salt spray so much, while the frame is otherwise in good shape?


Long story short, I found that the axles, at least the front axle, is a 1989 Dana 60, which differs from the 1990 due to the size of brake rotors and calipers. When I had asked, the seller told me he had gotten parts for a 1990 D70 axle when redoing it and the axles/suspension was from the 1990 swap. Wrong. (Seller didn't even do the D70 himself, the receipts show a different name - previous owner.) I originally bought parts for a 1990 D60 but found that the rotors and calipers just did not work. 1989 rotors and calipers did. (Side note, does anyone want to buy a set of unused AC Delco rotors for a 1990-up D60 axle? lol)

 

[James Ayres]

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(Front Axle Teardown Has Begun)
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(Down to the Knuckle... Next up, Kingpins)
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(New Lug Studs!)



I obviously decided to tackle the front axle first. If I planned on using the axles as part of a swap into a larger-cab truck, might as well do a good job. So I tore the thing down completely. New bearings, races, kingpins, seals, tie-rod ends, lug studs, and I took down every piece to clean, degrease, wire brush/wheel, prep and paint with rust reformer base and then top coat. I even snagged an old dishwasher off Facebook Marketplace to convert into an automatic parts washer to get it all done right. I drained the front differential, inspected inside to find it good, and resealed/filled. For this process I very much utilized Tyler Ovens' video on Youtube to learn how to do it, so thanks to Tyler for that. This process took me about a month, which included working only evenings when it wasn’t raining, and downtime waiting on acquiring tools, or parts to come in the mail. Note, I broke 3 different breaker bars trying to get the kingpins off. In the end, we used the trick where you drill a hole in a piece of scrap steel and then weld it to the kingpin and use a 4lb sledge to smack it and loosen them up. To install new kingpins, if you need a piece of 7/8” hex stock on the cheap, just run to Menards and grab a 1” wide x 12” long cold chisel, and cut off a few inches from the top. It’s a perfect 7/8 hex stock – I believe it even says so on the hang tag – and will only run you a few dollars. I didn’t get as many pics of this process as I probably should have considering the amount of work I put into this axle. But it turned out very pretty. I painted the knuckles, calipers and diff cover with a hammered copper color, and the rest in gloss black after using rust reformer on it all.

 

[James Ayres]

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(Axle Rebuilt & Painted)
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(I was looking for clearance, contemplating crossover steering)
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(Another view. I like that hammered copper paint)



With the axle done it was time to test drive. Brakes worked. The first highway test drive topped out at about 42 mph. I was starting to get a little frustrated at this point, and began looking at my transmission (and replacement transmissions) for answers. After a little more internet reading with some pictures, I discovered I've got a 47RH installed under there. The "webbing" on the exterior of the passenger side, the thicker adapter plate, the length of the transmission case, and the TV cable linkage all confirm this. So my friend and I found the 3-socket connector and traced the wires back into the engine box, and into the firewall. From there I traced the wiring to the cargo light switch and a secondary aftermarket switch that didn't seem to do anything. Long story short, after some more wire tracing (and connecting the loose tail ends to the battery ground), we found out that the cargo light switch was now the OD switch, and the aftermarket switch controlled lockup. After figuring that out, I can get the truck up and past 75 mph, but it’s still a chore on the 31” tires.


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(Transmission case showing the "webbing" on the passenger side)
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(Notice the much thicker adapter plate)



I found that the TV cable was actually seized, disallowing me to hit full throttle, so I had to replace it with a new Lokar cable. I tried to source the linkage for an A518/46rh but had no luck. So, I stuck with the cable and it seems to work fine. I also decided that I would like to get rid of the switches for OD and lockup, and rather have the trans be controlled by a standalone controller. Luckily the guys over at HGM Electronics started to redesign their Compushift Mini controller. I put in my name and number to be contacted when the new version is ready, and I actually just got a call in mid-February saying that they’re now back in stock. Once the weather warms up, the Compushift Mini is on the list of “to-buy” things.

 

[James Ayres]

At this point in late September, October and early November the weather started getting cold, turning to fall and winter. The project was on hold, except I started watching all kinds of videos and reading forums, facebook groups, etc. One of the video series I got onto was the 85 Crew Cab Swap from DEBOSS Garage. I really like the way Rich explains things, and that crew cab was looking awesome. So I abandoned the idea of finding a 70’s model Ford Supercab or Crew Cab, and turned my search toward a First Gen Dodge Crew Cab.


After several failed attempts to get one (you know, these things are getting harder to find nowadays), I was finally able to source almost exactly what I wanted. A 1985 W350 Crew Cab, 4x4 with D60 front and rear & NP205 t-case, 360 V8 engine, manual 4-speed transmission. This truck is super clean and straight. No rust. It was a California forestry service truck that had only recently made its way to Colorado. The box was replaced with a box from a 1986 donor, along with some other various extra parts. The interior is in excellent shape, and tan! Everything works. The suspension was recently changed to a Skyjacker Soft Ride 4” lift with lift springs all the way around (no blocks) and a single steering stabilizer kit.


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This is where I’m at for now. The plan is to take apart the crew cab and work from the frame up for a complete restomod. I plan to get started once the weather gets warm again (I don’t have a huge shop or anything), and right now I’m still daily driving my diesel truck. In the meantime, I’ll try to get a checklist going of all the planned things to get done.


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(Bringing it home)