Driveline resonance |OBS F350 7.3L Powerstroke SRW 4×4 rear driveshaft to pinion yoke ujoint repair

Truck developed a nasty driveline vibration at about 2000 RPM going down the freeway, causing the dashboard in particular to rattle and resonate.

Stabbing the accelerator up to 2500 RPM or simply lifting the pedal, would bring the truck out of resonance with an audible metallic clanking as the driveline unloads.

These are symptoms of a worn ujoint in the rear driveshaft (connecting the 10.25″ Sterling rear axle pinion yoke).

The ujoint hasn’t completely sheared apart. The cups first wear into the ujoint cross shaft causing the needle bearings to fall out and for the cross shaft to be wedged off-center in the yoke under the ujoint straps.

Single rear wheel 4×4, double cardon front and single ujoint rear driveshaft, regular cab long bed.

Found a replacement in stock at a local parts store and changed the ujoint in their parking lot.

Napa p/n UJ331

Tools needed:

Torx T-45 bit to remove the 4x driveshaft strap bolts,

Pliers to squeeze and remove the inner retaining clips,

Large socket as a drift and

Hammer to extract and reinstall the ujoint caps.

Mark relationship between balanced driveshaft and pinion yoke, to reinstall in the same orientation.

Apply penetrating oil to the ujoint caps at the yoke ears

The ujoint only has internal retaining clips outboard of the caps. Remove with pliers, and knock out the caps with the large socket and hammer.

Knock out one ujoint cup at a time, in the same direction. The ujoint comes out between the yoke ears.

Install new cups one at a time, using ujoint cross shafts to hold needle bearings in place.

Strike hammer against socket only, do not hit the new ujoint cap directly with a metal hammer.

Insert new retaining clips and ensure ujoint pivots smoothly.

(Smack driveshaft yoke ears with the hammer if ujoint is tight and binds.)

Reattach balanced driveshaft in marked positive relative to rear axle yoke.

Retorque bolts after test drive and wear in.

CEL P1391 & P1393 |OBS 7.3L Powerstroke | Glow plugs, valve cover gaskets & wiring harness, glow plug relay

Addressing check engine light for DTC’s P1391 and P1393: Glow Plug Circuit Low Input Bank 1 & 2.

Started by replacing all 8x Motorcraft glow plugs, but after checking resistance of each plug, found them all to be acceptable, low ohms.  Went ahead and checked resistance of new glow plugs and installed all new.

Next, replaced both valve cover gaskets with units from Napa Auto Parts (p/n 600-3501) which integrates the wiring harness between the gasket and under valve cover harness (UVCH) to eliminate the 2 connectors under the valve cover. 

For valve cover installation, there are tabs molded into the gasket to indicate the bottom orientation of the gasket. 

It is important to manage the wiring under the valve cover to ensure wires do not get pinched and short circuited above or below the gasket. 

A pinched injector wire causes a miss and can fry the glow plug relay and cause the truck to run terribly.

California emissions 7.3L Powerstroke glow plug relay with shunt.

Replaced factory glow plug relay (GPR) with a White Rogers unit https://amzn.to/3rlKmB5, and eliminated the shunt by connecting the ring terminals to the GPR post.

Creating a Craiglist saved-search for specific vehicle criteria

Use keywords and search criteria for specific vehicle features. A Craigslist saved-search can be setup for an email alert every time listings are posted that fits all search criteria.

For example, if I’m in the market for the newest possible California diesel manual 4×4 long bed rigs that are smog exempt, a saved CL search would look like the following:

  • Category: Cars & Trucks
  • For Sale: by Owner
  • Max Year: 1997
  • Fuel: diesel
  • Transmission: manual
  • Drive: 4wd
  • Keywords: long bed

Even with zero results with these criteria, CL will email an alert once a fitting ad is listed.

Another example, I’m in the market for a California smog-exempt manual Jeep to build as a trail rig:

OBS F350 aluminum topper & Phase 1 exo cage from lumber rack

Started sourcing major components by finding an uncommon Rack-It long bed lumber rack specifically designed with additional width to fit over a truck topper (also known as a camper shell).

One popped up locally on FB marketplace, and I jumped on it despite it begin mangled and sitting in a field of weeds.

It was designed for a crew cab long bed truck, so while cutting/welding/straightening the upper 1″ tube of the lumber rack, also lopped off 3 feet from the cab-over extension to match my single cab’s length.

Then, instead of reusing the forward section of 2″ OD tubing, I bridged the cut with a lower profile 1″ OD tube to reduce frontal area.

The lumber rack had large, 5/16″ thick footer plates intended to bolt to the top surface of the bedsides, so I trimmed them down to roughly 2″ wide to match the OD of the upright tubing, and welded and bolted them to my bed rails, which are capped and framed with angle iron.

Then, positioned the rack uprights at the very forward edge of the box to form a headache rack and halo over the cab.

Ran the rack for the time being with the fullwidth 2′ thick Weatherguard toolbox, while on the hunt for a topper.

Then, a Craigslist saved search with keywords: long bed & topper, produced a local hit for an aluminum contractor topper with single passenger side flip-up panel and rear swing out double doors.

Jumped on it right away because the seller had it on a likewise long bed OBS ford pickup, so no question about fitment. Pulled off my tailgate, brought along c-clamps and straps, and did the deal.

For reference, the following fullsize 8′ long bed topper accessories are compatible with an OBS pickup:

  • 67-96 Ford 8′ beds, 97 F250HD and F350 8′ bed
  • 73-87 GM 8′ beds and up to 91 3500 8′ bed
  • 72-93 Dodge 8′ beds

Also for reference, the following long bed topper accessories are NOT compatible:

  • 97-newer F150
  • 99-newer Ford Superduty
  • 94-newer Dodge
  • 88-newer GM

Upon taking delivery of the aluminum topper, was surprised by how lightweight the unit is even with doors and panel attached and how the seller and I could slide it forward under my existing lumber rack for a tight fit.

The topper is constructed of 1×1″ square aluminum skeleton ribs, skinned with painted aluminum sheet, and interior lined with thin speaker box carpet.

Once home, took the opportunity to cut and apply thick neoprene strips (intended to line a toolbox) between the bedrails and shell, then bolted it down with a dozen M8 fasteners.

The topper also has a dual slider window for access to the cab, but my single cab has fixed glass and something to address in case of emergency or to access the cab from inside the camper, which cannot be locked from the inside, nor can it be opened from the inside if latched closed from the outside.

With the tight fitting lumber rack, would have a vision to add triangulated tubes and build an exo cage around the shell.

With several 20′ sticks of 1.75″ OD, 0.120″ wall HREW steel tubing left over from a Jeep build, and an Affordable Bender (Model ab105 with 1.75″ mandrels @7″ bend radius up to 90*), started on the asymmetrical exo cage first on the driver’s side with no opening panel.

Phase 1 of the exo cage build was to cut full length rock slider tubes spanning front and rear wheel wells.

Kinked slightly with an apex between the cab and bed to follow the body lines.amd transition between cab and body.

Next, cut and notched another tube to tie the slider to the truck frame.

Then, a vertical tube with multiple kinks to follow the bedside while continuing the line of the halo down to the slider tube.

Lastly, added triangulated tubes from the mounting point nodes to the upper longitudinal tube on the driver’s side.

The cage is intended to be asymmetric right/left, by creating a tube node further back that center to support the rear crossbar that is still the pinned, removeable piece as opposed to notched and welded.

When bending and positioning the HREW, the welded seam is put towards where it will likely make contact with rocks and obstacles, and should be tougher to dent than plain wall; otherwise, bends are clocked 90* from the seam as to not stretch or buckle the weld.

Engine oil leak at cold start | OBS 7.3L Powerstroke oil cooler replacement

After a month of winter traveling at high elevation in Utah, truck developed a nasty oil leak at cold starts. Leak goes away after reaching operating temp, yet continues to weep oil after shutting down and cooling off.

Oil cooler exploded assembly

The 7.3L Powerstroke’s oil cooler is a tubular heat exchanger between engine oil and coolant along the driver’s side of the engine block, directly below the exhaust manifold. When it leaks, oil comes out past the O-rings at the tubular section between the front & rear mount (which is also where the oil filter spins onto), then drips on the driver’s side of the engine cradle crossmember.

View of oil cooler rear, and block heater cord.

Cold temps below water freezing point causes O-rings to shrink. These original units with 285k miles will not seal in the cold with Motorcraft 15W40 synthetic oil. (Not able to plug into a block heater while off-grid overlanding.)

California base and 200ft elevation, the motor doesn’t leak like that.

Parts to purchase for complete replacement

Requires draining motor oil and engine coolant.

Issues encountered

Ran into a rounded 10mm hex head on the upper mounting bolt, on the forward mount of the 7.3L’s oil cooler. Without taking any power steering or A/C compressor components off the engine, a 10mm ratcheting box-end wrench (12pt) can reach the bolt head with space to ratchet.

Left it in place and instead disassembled cooler while still on the truck. The assembly has 3 pieces pressed together from the interference fit of the 2x O-rings per side. The 2 ends are elbow bulkheads of motor oil and coolant, bolted to the engine block.

Starting from the rear, there are 3x 10mm bolts through the rear mount, which is shared with the spin-on oil filter mount.

Steps

1. Unplug the block heater cord & unbolt the heating element.

2. Unbolt the coolant drain plug. It will unload a bunch of coolant.

3. Remove the 3x 10mm bolts to unbolt the rear cooler mount.

4. Locate the pry tabs on the oil cooler cylinder, and pry against the casting of the rear cooler mount until it comes off.

5. Loop a ratcheting strap around the oil cooler cylinder with a slipknot held in place by the pry tabs; hook other end of the strap to the truck’s frame, and crank it off.

  • Upper left. Cooler’s rear mount and gasket.
  • Lower left. New gasket to the front cooler mount left on truck.

6. Assemble new heat exchanger and O-rings to the rear mount (smaller diameter O-ring outboard, larger diameter O-ring goes inboard), by squeezing them together between a floor jack and rear bumper or frame of the truck.

7. Grease the O-rings and sealing surfaces to prevent tearing or pinching or twisting; anti-seize on the mounting bolt threads.

8. Slip this subassembly under the truck and into the forward mount of the oil cooler. Use the exhaust manifold as a pry surface, and push the oil cooler into place and seat the forward O-rings.

9. Continue prying forward and parallel to the block until the 3x bolts line up.

10. Slip the new gasket between the engine block and rear oil cooler mount,

11. Refitted the coolant drain plug with RTV sealant,

12. Reinstall block heater element and cord.

To further mitigate winter cold starts, switched from Ford Motorcraft 15W-40 synthetic to Rotella Shell T6 synthetic 5W-40 (https://amzn.to/3mjktiq).

Since coolant was already drained, replaced thermostat with a Ford Motorcraft RT1201 190*F / 88*c thermostat (https://amzn.to/2VavAOB).

Reused the relatively fresh diesel engine formulated Zerex coolant (7 gallons, https://amzn.to/2JOlNvq) by pouring it back into the truck’s coolant reservoir through a 100 micron filtration sock.

Fire up motor and check for oil or coolant leaks.

Broken down on White Rim Trail | Buckled steering tie rod on Ford hp balljoint Dana 60 axle

Making good time on an anticlockwise loop of White Rim Trail, Canyonlands National Park, Utah.

Then, on a trail squeeze section buckled a brand new tie rod on the Dana 60 with all new inverted-Y steering components.

15:00 broken down steering, truck is undriveable through switchbacks.

With a buckled tierod, the wheels can be turned in one direction but not the other.

Steering looks like it is smiling. The tie rod connects the pitman arm to the axle.

No pickle fork in the onboard tool bag. Only basic hand tools.

Steps

  1. Start by removing the tie rod in order to straighten it out.
  2. Insert key in ignition and unlock steering column.
  3. Loosen the adjusting collar pinch bolts in order to turn the sleeve all the way out.
  4. Droop the tie rod; undo the cotter pin and castle nut of the connecting ball joint.
  5. Hammer strike the tie rod from behind the rod and not the ball joint (which damages threads).

Anneal the tie rod before bending it straight by using propane camp stove heat.

Use ratchet straps hooked over the ball joint and looped around the tire, to pry straight against the front bumper.

Straighten as much as possible; if possible, sleeve rod with a break bar tube or Hi-Lift jack handle.

Use box end wrench leverage on ball joint taper, not threads.

17:10 Truck is ready to roll again

OBS F350 7.3L SCLB 4×4 on White Rim Trail, Canyonlands NP Utah

Dropped into Canyonlands NP on a 2-day permit. Original plan was to enter from Mineral Bottom Road on arrival Day 1, explore that corner of the park on Day 2, then come out the same way.

Instead, would run the entire White Rim Trail in the anticlockwise direction, overcoming a trail breakdown with a clever self recovery, and connecting via Potash Road back to Moab in the dark.

From Island in the Sky visitor center, after picking up permits and topping off drinking water, exited the park and headed north back to Horsethief Road turnout.

Ran the dirt road (BLM129) which crosses Mineral Canyon Road and then reaches the top of the switchbacks, and descend to the banks of the Green River at Horsethief Bottom.

Top of the switchbacks

This section of trail is wide enough to be mostly doubletrack with turnouts for 2 way traffic.

White Rim Trail is a loop that follows the northern edges of the Green and Colorado Rivers, where they meet in the middle of the park. It’s in the Island in the Sky section of the park, where Needles is to the east, the Maze to the west, and lastly the rivers themselves.

Day 1

From top of the switchbacks

Entered Canyonlands again after continuing past Mineral Bottom Road onto federal land, where it turns into the White Rim Trail and begins to trace the Green River.

The sun at this point is about 4 fingers above the horizon, which at river bank level, the horizon becomes the tops of the canyon walls.

The search also begins for a boondocking campsite outside of the park, starting from the bottom of the switchbacks to the upcoming park entrance.

Entering Canyonlands on the rim trail at only late afternoon, drove into a squeeze section along the Green River just inside of the park. Very narrow, barely enough width for my rig alone between rock cliff and falling into the river. 

Hustled back over the squeeze section as to minimize chance of getting caught along with another vehicle coming in the opposite direction.

Made camp at a site with lots of bikepacker tire tracks about. Would come across several groups pedaling the trail with a chase rig.