Another Cummins truck: 91.5 W250, the "Blue Ox"


Aspiring Explorer
Partly inspired by member Metcalf's Doitall Dodge build, I decided to start a thread, now that it has completed its first offroad exploration outing (more later). I purchased this truck in February 2012, 300miles away in Catskill NY. It was purchased from the original owner, a 70 to 80 year old gent, who used the truck for camping. He had a large camper on the back, had beefed up the rear spring packs, added auxillary springs, added a rear sway bar, and a Warn XD9000 winch. It had 105,500 miles on it. I purchased it without the camper, went into to town to get registration and plates. Then we got on the 90 heading west for home.
It made the trip well, but wouldnt stay in OD for most of the trip, and once it drops to third, you need to press the pedal down hard to maintain your speed. Later on, I found that the TPS needed adjustment. It's still finicky around 40mph, so to any prospective buyers, either buy one with a manual trans, or be willing to tune up the several controls and swithces on the A518 auto, or be willing to swap in a manual trans. I feel my trans doesn't need a rebuild, its just a pain to me, one who loves manual trans. I changed the fluid and filter, and it was surprisingly clean inside, and I could tell from the gasket/RTV that it was serviced. Ofcourse Autozone tells you it should get the AT+4 (DON'T), so I put down the cash for 12qts of Castrol Synthetic Transmax for Chrysler vehicles, the bottle reads good for AT+7176 applications (The Owners Manual calls for AT+ 7176 or Dexron II). Shortly after this change, the tranny was shuddering in 3rd. YAY, more annoying auto tranny bull. After this, I got some opinions, did some reading on Dexron licensed fluid, then went to Walmart and bought 3 gallons of Supertech Dex/Merc fluid. Dexron II or III is no longer a licensed product. So I changed it again, and it hasn't slipped or shuddered since. Apparently the AT+4 is too thin and too slick, probably even worse when its synthetic. Others in the Internetverse have commented that the 20 year old "frictions" or clutches are not compatible with the slick fluid.

My fluid changing process is the following:
1) Drop the pan, measuring the amount of fluid removed by draining into a graduated bucket (use a 2 liter or 2qt bottle to mark increments)
2) Change filter, clean pan and put pan back up with new gasket.
3) Refill amount removed
4) Add 1 extra qt (lessens risk of running trans dry)
5) detach "hot" line to cooler and attach a drain line into graduated bucket. For the Dodge trucks, trans should be in neutral, so fluid is pumping
6) Start and run vehicle for 5-10 seconds, checking how much fluid comes out. Target for 2 qts removed
7) Replace 2 qts removed with fresh fluid thru dipstick tube
8) Repeat 2 or 3 times (Cummins A518 stock pan held about 6qts for me, and I took about 6qts out of the cooler line for a total of 12qts replaced)
9) Replace 2qts each time except for the last time, add just one and you should be back to original amount before started
10) Take it for a long drive getting the fluid warm to hot, follow fluid checking process, while idling in Neutral

In February, we also moved into another home needing lots of updates, with an acre to lots of stuff to maintain. My purpose in buying this truck was to have a truck to do everything. Haul cars, get building supplies, pull out stumps, plow my long driveway (Buffalo snow belt), give me the ability to run alternative fuels, offroad and explore. The only thing it has left to do from that list is plow my driveway, but should get that chance shortly, after I install the plow bracketry.

So this truck was in need of a lot of improvements, refreshing, and maintenance. Here are the things I have done so far to this writing:
1) Changed the oil with Rotella Syn T6 5w-40 and a Napa filter. Goal: keep it good for another 20 years. Like Metcalf, I found it takes about 13 qts to reach the full mark
2) Put in a new oil pressure switch
3) Pulled of some of the PO's auxillary stuff, the aux springs, the bars to tie down the camper, the rear sway bar. I still have to pull the 2 rear extra leafs per pack
4) Replaced the brake master cyl, hard lines from master to the front and rear axles.
5) Purchased 16x7 8-lug Ford Van wheels (or F-250/350 wheels to '97). The backspacing is ~4.25" about the same as the stock chrysler 16x6. Warning: you need to change lug nuts! Ford wheels require 60* taper vs 90* for 1st gen cummins trucks. The part number I used from Napa was:641-2147 or ask for appropriate Ford fitment lugs. Note: the center bore is about 1/8" larger so they wont be hub centric.
6) Purchased a set of Treadwright 285/75-16 Guard Dog tires and mounted them on the Ford wheels
7) Installed a new steering Drag link TWICE. The Chinese ones are as cheap as $28 bucks (EDIT: and junk), The Moog (made by TRW) is made in USA, and it way better quality
8) Extended the front, rear axle and NP205 transfercase breather hoses.
10) Designed and built a beastly rear bumper. I can add some more pictures of this feature later
9) Just completed a front brake overhaul, with Fresh rotors, Severe Duty pads, and rebuilt calipers, all North American parts. While it was all apart, I installed fresh bearings (USA) and grease in the hubs. Fortunately, both hub internals and lockouts were well cared for and in excellent shape. No rust and no grey watery grease inside. I also purchased a stub shaft bearing grease tool from I had best success with both axle nuts removed using this tool

My nickname for the truck is based on Paul Bunyan's trusty workmate: "Babe, the mostly Blue Ox" which I shorten to "Blue OX". To me, this truck has a little more value in that the original owner had used the truck for camping and exploring. I have been very happy with my purchase. I enjoy freshening it up and plan to keep this truck and mod it over the years. I dont want to spend a lot on it right away, and I have time to slowly upgrade it.

Last edited:


Aspiring Explorer
Here is a video showing the steering stabilizer kit I installed on the truck. My truck was getting "death wobble", probably mostly due to the drag link being worn out. But this kit squashed the wobble even with the bad drag link. It did add a little steering effort, for the most part only noticeable when turning sharp
Moog part number is ssd11


Aspiring Explorer
Here is a mod I did a few months back to my truck to improve the water fording height. The stock air box has a rectangular tube that points down to behind the front bumper, which is about 30" from the ground on a stock truck. That means you cant even go in as high as a stock tire. I realized that if you rotate the stock airbox about 150 degrees CCW, you could increase the inlet height to about 44", and have it rear facing. To ford water that high, however, you would need to add a gasket or a foam seal to the lid to keep water out. The other benefit of this mod, is that it could be a starting point for a snorkel. This is also a good mod to those folks who live in areas prone to flooding, or flash flooding. It would be a shame to have a mighty Cummins engines life cut short due to sucking water.

Here is the stock airbox in the factory position

You can see the rectangular tube aiming down to the front bumper, its like a straw to pull some milkshake into your airbox.

Here, I drilled a new 3/8" [10mm] hole to bolt the airbox to, about 1" from the seam shown

Keep the center line of the air filter approximately inline with this nut (mines a '91.5 intercooled). I also angled the filter outlet a couple degrees towards the turbo.

On the right, I bolted the thick plastic slot on the airbox to the new hole I drilled. On the left, I used an existing hole in the front clip, and drilled through the airbox and inserted a bolt. I also placed an 1/8" thick washer beneath the steel flange to take up the difference so you dont stress the plastic airbox.

The airbox inlet now faces rearward, hopefully being much more resistant to splashing water. Remember that a seal should be added to the airbox lid before the lower portions of the airbox are to be submerged

Final location of the airbox

I had to trim the wings off the one wingnut near the coolant overflow bottle. Notice the gap between the airbox and the lid. This is why a seal is a must to get the most fording depth from this mod. Even if you do not add a seal, you have added several inches to the fording height, and your truck is now resistant to the wall of water you are pushing around with your front bumper in a typical water crossing.

I had no issues with the stock intake tube not fitting. I did have to move my A/C dryer over about 1.5"


Aspiring Explorer
I just completed a great mod for driveability, which is moving the throttle rod to the inboard hole on the throttle lever. When I went to do this, I cracked one of the plastic ball joint ends on the throttle rod, you can see the cracked plastic end at the bottom of the picture. A google search showed up some Cummins part numbers for new metal ball joint ends, which I believe are from the 2nd gen '94-98 trucks. The cummins part numbers are: 3990093 & 3990094 , they were about $11 each from Cummins. NOTE: since I moved the throttle rod inboard, I did have to shorten the threaded rod by about 1/4" on one end.
The driving experience is much improved, which much reduced foot travel on the go pedal.



Aspiring Explorer
So on Thanksgiving day, some friends and I made it out to go do some exploring, which would be my 1st outing with the truck. I had always wanted to get back to Allegany State Park, to learn more of the trails and geography. The day trip was about 135miles round trip from home and back. Fortunately, the ground wasn't sloppy mud, we were going to explore, not go mudding. The truck did very well, and the Treadwright Guard dogs in 285/75-16's performed well even at street pressure, about 40 psi. The suspension is currently stock as of this writing, save for the previous owner adding 2 leaves per pack in the rear springs. That makes the truck not so flexible in the suspension, probably getting a lot of flex out of the frame. I also noticed the weight for sure of the Ox, especially uphill with a muddy washed out trail, but it did supprisingly well up some steep grades. I was trying to crawl up it, but had to lay into a bit. Also my diffs are open.

Here is a bridge crossing video, and you can see how annoying the auto trans stock converter and laggy 21cm turbo housing combination is. Again, 1st outing with the truck
My friend in his light Tracker 5spd makes the crossing look easy, again showing the difference weight plays into offroading.

After crossing the bridge, and following the trail for a bit into a field, we turned around and I was persuaded to try crossing the creek against a sharp bank. My stock sagged springs and 33" tall tires weren't enough to keep my winch tray from sticking into the bank. I was prepared with a shovel, but I bought the Chinese shovel to save $15, the handle of which snapped on the 1st try, showing the importance of having good equipment. We had a good belly laugh, and learned that lesson again. Fortunately, my freind, seen standing in front of my truck, also brought a shovel that was more stout, and with a little digging got it unstuck. My winch also had stopped working, which I later found out was a jerry rigged solenoid connection.

It was a good time, nice to be exploring the outdoors, and testing the truck's capability, and seeing the weakpoints. I am planning to install some new front lift leaf springs shortly and refresh the rear spring pack and remove the 2 extra leaves and maybe 1 or 2 more. I have already purchased new u-bolts for the rear springs, so in the next couple weeks or so.
Last edited:


Aspiring Explorer
Im working on a new front bumper design incorporating a winch and hyd plow lift



Aspiring Explorer
Which grille side tube looks better on a 1st gen Ram, the straight or the angled?



I like the straight bar, but both look good. Cool build, you've sure made more progress than I have on my truck.


Aspiring Explorer
I like the straight bar, but both look good. Cool build, you've sure made more progress than I have on my truck.
Thanks, I was favoring the straight bar all along, but tried out the angled look today on the computer. I just had a thought today that I could mount lights on the straight side bars either side of the main grille loop. Before I was always thinking they'd go on top of the main grille loop.

Very nice, liking the simplistic look of the truck. How are you liking your Treadwrights?

Thanks, the Treadwrights are ok, but i had one flat spot which they replaced, and the rears are wearing quickly in the center when I was running them at only 35 psi. I since dropped them to 25-30. Maybe its my fault for mounting them on a 7" rim, and its pinching them in?
Last edited:


Yeah, that's kind of what I expected to hear. I guess you get what you pay for, considering a similarly sized mud terrain is usually 30 or 40% more money. Good luck with the build! Love seeing these 1st gens revived.


Renaissance Redneck
For your grill guard, the straight bar looks like it should be on a 2nd gen. For your first gen, I figure the bars should be the same height all the way across to match the hood. Would the lower bars be below the headlights? I'm just not seeing how you are planning to make it work. Can you super-impose the grill guard cad drawing onto a pic of the front of your truck?