Cabover HMMWV Expedition Truck Project

[zioxkoa]

General progress update: got my custom clocking ring to adapt the Allison 1000 to the NP242. All the off the shelf rings couldn't do the angle I needed so a friend machined this for me. I accidentally gave him the wrong bore sizes on the first iteration so it's now made 3 trips across the country ?‍♂️. But everything looks good with it on the truck now!

I wasn't sure if I'd be able to reuse the rear driveshaft with the Cummins/Allison/Tcase being ~2" longer than the stock drivetrain, unfortunately it looks like it won't fit. So new drive shafts or extending the old drive shafts are in order. With the NP242 installed I was also able to test fit the fuel tank and it fits as well (hopefully still does when there's a drive shaft next to it).

On a standard Hummer/HMMWV the fuel tank is attached to the body and not the frame rails, so I'll need to fabricate some supports to hold it in place. I'll also be making a winch cradle that will double as a brace at the front of the frame extensions to help tie everything together.

More to come in the next few months!

 

[cabnetguy]

Denied! The truck porn doesn't show up!
Need something to break up the boredom while I wait for Ian to hit us

 

[zioxkoa]

Doh! Should be fixed now, still getting the hang of this forum. Thanks!

 

[cabnetguy]

Yep they work now.
Thanks

 

[KiwiMtnClmbr]

This makes me feel so inadequate...

 

[I play outside]

There is so much right with this build. HUGE fan of 6bt. smart like tractor. Rock simple. How you gonna manage the Alison? i think there is turnkey standalone management or some diy that seemed pretty cool as well. Tons of work ahead of ya. Dont steam. this will be killer.

 

[Oka 374]

I have a 6bt and 6 speed Allison in my 4wd OKA campervan here in Oz, I used a wiring harness and TCU supplied by transmissiontuner.com, Jason built the harness to suit the truck using my measurements to place plugs and connection points to the truck, the whole setup has now been running without a hitch for over five years in many outback trips.

 

[zioxkoa]

I have a 6bt and 6 speed Allison in my 4wd OKA campervan here in Oz, I used a wiring harness and TCU supplied by transmissiontuner.com, Jason built the harness to suit the truck using my measurements to place plugs and connection points to the truck, the whole setup has now been running without a hitch for over five years in many outback trips.

Awesome to hear, I've also gone with Jason from transmissiontuner.com. Decided to go the custom harness route based on my odd routing needs, but it's been sitting in a box for the better part of a year now. I ended up buying the TCM and kit before deciding to swap the cab, which set me back a few months to say the least ?

 

[dentedvw]

This is fully rad. Looking forward to future updates!

 

[SDDiver5]

Speaking of updates. What the heck man we need some recent pics!

 

[joeblack5]

Very nice choices you made with your design.
It is looking great. I am fooling around with a 404 unimog but you are taking this to another level .
Johan

 

[zioxkoa]

Thanks for the kind words and apologies for the delay on updates, been too busy to post! I went through and replaced all the frame extension nuts with top-locking distorted-thread grade 8 nuts (been on the backburner for a while, ~40 total) and reinstalled the front suspension now that the extensions are done. This was the first time back on the ground under its own weight since the cab swap, so it's nice to be able to roll it back and forth again.



I ended up taking a 3d scan of the frame and drivetrain to help with the design going forward, but more immediately so that I can ensure the steering u-joint angles are happy. Took a long time with my little Revopoint but eventually I got a usable model that's a composite of ~100 individual scans:




It's not perfect, but good enough for my purposes. Using this scan I was able to get a good design for the steering routing and angles, then picked up a pair of miter boxes and some of the ujoints to make sure it all fit.



Next up is designing and fabricating the steering shaft heim and miter mounts, but I'm hoping to double those up with some other mounting (intake/exhaust/cooling/etc) so I can pack it all in there neatly.

 

[ExpoMike]

Hell ya!!! That's a cool scan and figuring out the steering shaft.

 

[joeblack5]

Any particular reason you positioned the heim joints so far from the double u joint in the middle of your model. This way you might get some bending forces on your steering shafts and possible some vibration.?

 

[Jrheld]

Hi,
I am currently traveling for 9 month now with my Turck based Camper (7.4m long, 3.35m tall, 2.38m wide 7.5t) from Europe to central asia and back.
This all in all went well so far, but I was thinking that a smaller and lighter vehicle with more driving comfort would probably be a better choice (for the next time).
So I came up with a pretty similar spec then you did, hence I came to the same conclusion... HMMWV
But its actually only the suspension, ctis and classified weight which is attractive.
So I googled... saw that hmmwv cummins swap is kind of a common thing, which is great.
So I goolgled hmmwv body swap and ended up here ;+D which is even more great.
I would have more aimed for a kind of bus/van chassi, but anyway you have an interesting project going here and I am following along with couriosity.
AloHa
Jakob