The Truck of Theseus (2 Viewers)

[littlevulture]

Table of Contents​

updated 5 March 2025

My Project Notes (hosted on Github) - see Post 15 for more info about this
FJ Cruiser Mirrors Initial Install
5VZ-FE Swap
Solid Axle Swap and Ford 57's
VF4AM Top Shift Conversion

 

[littlevulture]

After many years of ownership and neglect I've started an official rebuild of my truck. I bought it in 2017 while I was in college when I realized I that despite growing up turning wrenches on dirt bikes I wasn't really confident I could maintain a car. So I bought this as a project and used it as my daily until 2020 when I graduated and bought a new car. After that the truck sat in storage while I moved around the country for work for a couple years. I never really got to do anything fun with it but it was a fun project and learning experience. I built a bed to replace factory one that rusted away to nothing, swapped a 5VZ in after I stupidly ran the original 3VZ out of oil, and solid axle swapped it because it seemed neat. A couple years ago I attempted a fairly successful rear full float conversion with disk brakes. This was just a good excuse to drag the truck out of storage and keep me entertained while I was waiting on some upcoming life changes so it still needs a v2 with some updates.

At this point the truck needs a full rebuild of everything...mechanical, electrical, interior, exterior but the first phase is getting it back to running and driving reliably. The 5VZ is having intermittent problems that I can't diagnose or replicate, the steering needs redone, the bed is bent and rusty (I'm a lazy painter), the transmission probably needs a rebuild after roughly 350,000 miles and so on. I've got some unique plans that I'll go into once I start posting details of the rebuild, but for now I'll share some of my old pictures from my old mods in upcoming posts. For anyone who's a nerd like me, The Truck of Theseus is a play on words coming from The Ship of Theseus, from Wikipedia, "The Ship of Theseus, also known as Theseus's Paradox, is a paradox and a common thought experiment about whether an object is the same object after having all of its original components replaced over time, typically one after the other." I think it’s fitting since the truck is a mashup of parts from all over and it's only going to get less original as I go on.

Big picture, how the truck is currently configured
- 1988 Toyota Pickup Xtracab SR5
- Engine: 5VZ-FE Swap, 1997 3rd gen 4Runner donor
- Transmission: R150F, 1988 original transmission
- Transfer Case: VF1A, 1988 original transfer case
- Front Suspension: 1988 rears up front
- Rear Suspension: Ford 57's from an early 2000's junkyard F150
- Front Axle: SAS with a 1983 axle, 1988 IFS hubs, 2006 Tundra brakes (can't remember which caliper), homebrew z-link style steering
- Rear Axle: 2015 4Runner rear disc brake (14BD caliper) and full float conversion using some brackets I designed
- Bed: A flatish bed that I built as my first welding project

Rebuild Plans​

- Engine: 2011 VW CJAA common rail TDI, donated by my totaled Jetta Sportwagen
- Transmission: R156F, purchased from a totaled 2TR powered 2016 Tacoma
- Transfer Case: VF4AM, purchased from a totaled 1GR powered 2006 4Runner, I'll be attempting to convert this to twin sticks
- Front Suspension: Spring under and shackle forward using 3rd gen pickup rears
- Rear Suspension: No changes planned aside from removing a leaf or two and replacing bushings
- Front Axle: Flip it to work with the driver drop VF4 case and build more robust steering
- Rear Axle: Finish the full float conversion, it's perfectly functional but I have more tools and space so it's getting a v2 that should be a little better
- Bed: Build a new flat bed, hopefully out of aluminum so I don't have to paint it
- Other: Refresh everything that's been neglected over the last 36 years (brake lines, fuel lines, radiator, bumpers, lights, etc...)

 

[littlevulture]

Shortly after I bought it I joined up with a club from Colorado School of Mines and went wandering in the Rockies for a day. The trail was a solid sheet of ice so we didn't make it far, my very bald and dry rotting tires certainly didn't help at all.

 

[littlevulture]

The truck was missing the driver mirror when I bought it and the passenger mirror was a broken housing with a generic piece of parts store mirror glued on. I had seen a picture of FJ Cruiser mirrors on a 1st gen 4Runner so I decided to give it a shot. I had to grind down the mounting posts and remove the wiring bracket so I could tuck the plug up in the body of the mirror. They won't sit flush against the body without those changes. After a little templating for new mounting holes and an access hole for hardware installation they were installed. This has held up great so far, but I have ideas to make a stronger mounting system at some point during the rebuild.

 

[dohcdelsol93]

What are your plans for the intercooler?

 

[littlevulture]

What are your plans for the intercooler?

Haven’t decided yet. I have a lot of work to do before I get to that point but initial measurements say a generic front mount will probably fit behind the grille with a little trimming. Something like this…

 

[littlevulture]

More old pictures of building the replacement bed, rear bumper, and tail lights. In an attempt to keep it lightweight the structure was 2"x.5"x.125" channel. In hindsight this was far too lightweight because the bed is bent in multiple places now from strapping things down. Initially I had a plywood deck and some scrapwood bedsides but eventually I replaced the deck with 1/8" aluminum diamond tread and built some removable steel bedsides but I never got around to filling the gaps in the new bedsides with panels. I did no prep and spent minimal time painting so this is all rusty junk now.

 

[littlevulture]

Spent some time this week doing a mockup of my new driveline and doing exploratory disassembly of my new to me VF4 transfer case. I've got lots of interesting stuff to share upcoming but for now more old pictures...

5VZFE 3.4L Swap - The Donor​

There's lots out there on this subject already so I'll skip most of the technical jargon. I bought a rolled 1997 4Runner from a guy who got it from a highway patrol auction. Picked it up in Grand Junction and drug it back on a UHaul trailer to Boulder and stuck it on the yard side of the house for disassembly. Fortunately we had an absent property manager, neighbors who didn't care, no HOA, and lived just on the outside of the city limits so nobody cared about the 4Runner sitting in the grass.

 

[littlevulture]

5VZFE 3.4L Swap - Pulling the Motor​

Once the donor was in place we pulled the engine, ECU, and relevant wiring. Using standard engine hoist on very uneven grass was a bit sketchy but the whole thing only tried to fall over a couple times. The new "flatbed" was super useful being able to use the truck as a work surface and also get the engine moved around without worrying about damaging any sheetmetal. Once the engine was in the garage I replaced seals, did the timing, and all the other little things that are easier with the engine not installed in a vehicle. In the last picture under the workbench you can see my "new" solid axle which was a project for the following summer.

 

[littlevulture]

5VZFE 3.4L Swap - Disposing of the Carcass​

Eventually the 4Runner shell got moved to the driveway and cut apart. From there it went into the bed of my old truck and off to the recyclers.

 

[jgranthevagrant]

Next time just throw a sheet of 3/4 ply under the engine lift. Helps it roll and it doesn't try to tip as much.

 

[littlevulture]

Next time just throw a sheet of 3/4 ply under the engine lift. Helps it roll and it doesn't try to tip as much.

Yeah in hindsight that would have been smart...but being dumb and new to this whole thing it didn't cross my mind at the time.

 

[littlevulture]

5VZFE 3.4L Swap - Engine Install
After this we installed the engine, the big thing that we came across that wasn't evident in the swap info online is 1988 used different motor mounts than every other year of 3VZ/5VZ applications. The 1988 3VZ mounts are incompatible with the 5VZ so I had to go get a set from the junkyard. The mount in the back of the first two pictures is the 1988 version and you can see how different the motor side of the mount is, otherwise the frame side is all the same. To clearance the hood for the taller intake I cut out the bracing in the middle and slammed the hood really hard which put a nice clearance dent in it, the hood already had some damage so I didn't feel too bad about it. But after driving it for a couple years I've decided this is a bad idea overall since the hood still contacts the intake and it has slowly ground a large flat spot onto the intake as the engine vibrates against the hood.

Up next, solid axle swap and Ford 57’s, then my prototype rear full float and disk brake conversion. After that I’ll finally get onto the fun new stuff like my plans to convert my VF4AM electric shift case to top shift.

 

[littlevulture]

Solid Axle Swap and Ford 57's
Onto the solid axle swap and rear Ford 57's...starting with all the parts loaded up on the bed plus an old engine from an Izuzu trooper my roommate had that I took to the recycler. I was doing all the work at my parents neighbors house which was about an hour away from where I lived so I went home over the weekends after work in the summer to work on this. He's managed to stuff a fully functional shop into a residential 3 car garage. The perks included lots of tools and help as I figured out how to actually do this work, the con was the truck had to be mobile to move out of the garage at the end of each day which gets tricky when you're cutting off the suspension.

We did the rear first because it was much simpler so it made sense to start there as a warmup.

When that was all done I finished assembling the front axle and rolled it over. The wheels are the 8 hole FJ Cruiser alloys which I chose because they had the most backspacing of any factory Toyota 17" wheel at the time so I could run them without spacers. I did end up needing 1.5" spacers but I later discovered I could remove those when I did the rear full float conversion a couple years later.

Then we cut off all the old stuff and put in the new stuff. I never did go back and finish removing the brackets from the frame, mostly because it was a lot of work and I was running out of time to keep using the neighbors garage. Soon, when I pull the axle to put in the VW TDI I'll actually take the time to clean everything up and do it right.

Shortly after I took the truck home with the new suspension I found myself parked next to the Turtle III Expedition Truck in Boulder, CO which was pretty neat. The last two pictures are the crossunder z-link style steering I came up with. I really wanted the truck to be as low as possible and this was critical to keeping the drag link out of the frame. The links were I think 1.5x0.22 wall DOM that were bent with a JD Fab style bender. I had two versions of this steering, after the first one didn't work out like I imagined I had to extend both the tie rod and drag link. To do this I made an extension then internally sleeved and plug welded the extension in multiple places. Maybe not the best way to do things but I didn't want to buy a whole new stick of DOM and threaded insert sleeves to make new parts. I was going to add double shear to the joints but I never got around to it before I parked the truck after college. None of this matters now because I have a new steering design in the works that will use FJ80 rod ends and straight links.

 

[littlevulture]

Parallel to this thread I have started a Github repo that has all my notes and reference documents in it, I can't confirm it but I have to assume that I am the first idiot to use Github for something like this.

Though this is the first time I'm actively participating in any forum I've been lurking long enough to watch threads, images, documents, or even whole forums drop offline and take valuable information with them when they go. Between the TDI swap, transmission upgrade, transfer case shenanigans, and everything else I'm doing I've done an unreasonable amount of research for this project, and I've been slowly taking notes and collecting source material as I go. In an attempt to preserve and consolidate everything I've learned I'll be periodically pushing a copy of my notes and references to Github, these are all live documents that will evolve as I edit them for my own reference. This only takes me a couple seconds to maintain since I'm already writing the notes for myself and maybe it will be useful as a reference for someone someday. For example, my borderline unhealthy obsession with the VF4AM transfer case has led me all over the internet trying to learn everything I can about the VF4 transfer case family. Unfortunately any useful information is fragmented in dozens of threads across multiple of forums. As I've collected information it's been consolidated into my notes (with sources!) where I am slowly building a personal VF4 tech manual...now it's on Github where other people can read it too. As the project continues anything I find useful and might need to reference later should (if I don't get too lazy) end up there so eventually it will have more fun stuff about R series transmissions, VW common rail TDI swapping, etc...

I use software called Obsidian to manage my notes and they are easiest to read with that app, but they're still fairly readable in Github where they can hopefully exist forever.

 

[littlevulture]

For some current progress, I just finished doing some exploratory disassembly of my original VF1 and my new VF4AM to see what a top shift conversion is going to require. Surprisingly it looks like it's going to pretty straightforward even though this case was never offered with any shifting mechanism other than a dial on the dash that sent commands to a 4WD control computer.

Starting with a quick picture of the new R156/VF4 on top and the old R150/VF1 on the bottom. It's a little hard to tell but the VF4 is longer to accommodate the torsen differential inside. After I split the cases apart I measured the front part of the VF4 housing at 8.625" and the front of the VF1 at 7.4375". After converting to metric I get 220mm for the VF4 and 189mm for the VF1, so the VF4 is 1.1875" or 31mm longer than the VF1.

Here's the critical bit that is going to enable all of this nonsense, the top back of the housing is already machined with guides for lever actuated shift rails. I'm assuming they use the same casting for all the different VF4 versions and add machined features as needed and at least in 2006 the VF4AM got manual shift rail guides machined at the top of the case, even though they were never used for anything. The shift rail detent hole locations at the back of the housing and the shift rail clearance holes at the front of the housing are marked but not machined out, but those are the easy ones to add. If the guides at the back of the case were not machined already I don't have any idea how I would accurately locate them or setup the housing for machining.

Here's another general comparison of the two cases (VF4 top / VF1 bottom) after splitting the housings although I did already remove the high/low shift rail and fork from the VF1.

And the VF4 after I removed the shift collars and rails from the electric shift mechanism. The whole torsen differential and drive mode selection mechanism is very compact and fits in that little collection of gears.

I tried to order all the shift parts from a 6 speed FJ Cruiser to retrofit into my case but the shift rails and forks aren't readily available on any of my normal parts sites. Unfortunately the shift rail holes in the electric shift forks don't line up with the top shift rails so somehow I'm going to need a set of the unobtainable FJ Cruiser shift forks. The FJC high/low shift fork and rail would work 100% out of the box but the drive mode select rail was going to need the detents welded up and new detents added so maybe this isn't such a bad outcome after all, assuming I can still get my hands on the forks themselves. Since the rails are 15mmd diameter I can probably build my own shift rails out of some 4140 or 1045 15mm round bar, McMaster just happens to stock both of those. The only part I'm not sure about is the factory shift rails are hardened and I can't figure out why. I tried a couple files on the rails and they would scratch the surface but not bite enough to remove any material. Anyone have a good guess why Toyota would have hardened the shift rails and should I harden any new ones I make? My gut says it's not terribly important.

Aside from that the shift forks from the VF1 fit in the guides at the back of the VF4 just like they're supposed to be there. Kinda cool that nothing has really changed from 1988 until at least to 2006, but it's probably still the same today.

One last picture where you can see the shift rails peeking out in the shifter mounting location. Unfortunately since this case is longer than the VF1 they're too short to work but it proves my idea should work.

 

[littlevulture]

Does anyone have some definitive idea if shift forks are cast or forged? I'm leaning towards forged, this guy on old pirate says forged normally has thick seams from the forging dies and will ring if struck like a bell which are both indicators I've read about on other sites too. Since I've exhausted all the options I know about trying to find the shift forks for a top shift application I think I'm going to attempt to modify my existing shift forks. Assuming these are forged and I can weld them somewhat effectively after burning all the gear oil away I can cut a piece out (roughly between the red lines) and move the shift rail hole down so it lines up with where the new shift rails will go.

Anyone have thoughts on this? It sounds reasonable in my head but that's really just an echo chamber for stupid ideas.

Very thick "parting lines" on this fork, making my think it was forged between dies instead of cast.

 

[Lucille]

Do you have a parts t-case that you could rob a shift rail for weld testing? Even if its cast, you should still be able to weld it with the right filler material.

 

[littlevulture]

Do you have a parts t-case that you could rob a shift rail for weld testing? Even if its cast, you should still be able to weld it with the right filler material.

I don’t but these parts are useless if I don’t modify them. I guess I could just cut them and see what happens…otherwise my best bet is buying a fairly expensive case from a manual FJ Cruiser and stealing the right parts and totaled FJC’s aren’t exactly plentiful in Kansas.

 

[The Machinist]

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