GMC Topkick 4x4 Expedition Camper Build

[Coachgeo]

Been working on frames to mount the panels on the roof. The front one is almost complete.
5" channel sides to give some protection from branches,...
There were a couple of really good welds - "like stacked dimes" The rest were like "stacked rocks" !! ...

Better than I can weld.
At some point.... and it can be post mounting maybe? Use a hole saw and drill some large holes in the aluminum channel to help air move out from below?.

 

[Britboaters]

Finished up the rear solar panel frame today - waiting for the gas struts.
It'll lift to about 40 degrees, so will hopefully have some value. Cost about $150 extra to do it, so I hope worthwhile.
Used the skidsteer to lift it on to the roof. Really couldn't have done this project without this machine !
The box is in still in the shop, so not enough headroom to get a shot of the panels on the roof - need to be patient.

 

[Sixinarow]

Looking good! I'm toying around with the idea of a Topkick or Kodiak, also.

We're a family of four, me, wife, 4 year old boy and 6 month old boy.

I've looked at full-size vans and they're too small. I've been looking at International 7400s and Freightliner M2 106s and they're big and tough to find in crew cab 4x4.

So, now I'm looking into these!

 

[Britboaters]

Sixinarow, 4WD are pretty rare, and a 4WD crew would be tough to find. Then there's the wheelbase. The ones I've seen seem to be fairly short. I would suggest a minimum 14 ft box - that would need about 217 or 229 wheelbase. Mine is 188 with a 14 ft box. A crew cab with a 14 ft box would be about 28 feet lon overall.
Mine will weigh over 16,000 wet when its finished; including 60 gallon of water and 70 gallon of diesel. I'm getting close to the GVWR; mine is a C4500. I've got a big solar system, with 8 golf cart batteries that weigh about 700 lbs with the necessary racks.
My point being to be very careful on the weight while planning your build, as you will soon get up to the GVWR. The C5500 has a heigher GVWR, but the front axle is rated at 8,000 lbs from memory.
I used a new aluminum box that weighs about 2,200 empty. I'll add about 600 lbs to finish the walls, including lightweight studs to thicken the wall / ceiling to 2.5" & 3.5" respectively; spray foam and interior FRP walls, total of 2,800 lbs. You could perhaps use a composite box from somebody like Total Composits and save some weight, mayber halve my box weight.
There was a thread on here of a guy doing a really nice build on one of these trucks, but he got much too heavy for the truck and ended up putting the box on an international chassis from memory
https://www.expeditionportal.com/forum/threads/c5500-topkick-4x4-crew-cab-build.45835/
The reason I went with the GMC rather than a Ford or Dodge was the higher rated front axle, and much better visibility. Coming up the switchbacks from White Rim Road, near Moab UT, in my Ram 2500 was no fun with my wife terrified because she couldn't see the road !!
I wish you all the best, and if I can help at all please don't be shy.
Bob

 

[shortbus4x4]

There are a few International 7300 crew cab 4x4s on GSA Auctions in VA right now.

 

[Britboaters]

Working on electrical rough-in. You can see all the cables from the solar coming down thru the wall.
Also all the 12 volt circuits for lights, fans, etc that need to be in the wall. I used 14 ga for all circuits.
Most of the other wiring for fridge, water pump, etc will be run in the cabinets.
Will also rough in 120 for microwave and a receptacle by the counter...
I tried to use little plastic grommets to protect the wires, but I couldn't get them to stay in place, so used bits of PEX.
It's a real pain to stick the wires to the walls / ceiling before sprayfoam - duct tape just peels off.

 

[Britboaters]

Roughed in the plumbing also, using 3/8 PEX. Plenty of flow capacity and fairly easy to bend. Put some styrofoam blocks behind the PEX to hold it away from the walls before I get it spray-foamed. Had a real problem locating the shower valve, so glued a piece of plywood to the wall with a little "socket in it to locate the valve. Unfortunately no insulation behing the valve, so I won't put any in front either so it shouldn't get too cold, I hope.
We're using a regular 32" shower stall from Lowes, with a regular Moen valve, for reliability.

 

[Britboaters]

We used regular RV windows, that come with a trim ring for wall about 1 1/2" thick. This won't work as our walls are 2 1/2" thick. After a lot of thought, we cut narrow strips of painted aluminum "trim coil" the correct width.
We then laid this in the little groove in the window extrusion, and riveted the ends together to make a hoop the right size.
We then set these hoops in the little groove and put some adhesive to hold them in place. Once we spray foam, that should hold them nicely in place. Them we're planning some "PVC angle iron" bent to shape and glued to this aluminum and the finished interior walls - well that's the plan .....

 

[aernan]

Looking good! I'm toying around with the idea of a Topkick or Kodiak, also.

We're a family of four, me, wife, 4 year old boy and 6 month old boy.

I've looked at full-size vans and they're too small. I've been looking at International 7400s and Freightliner M2 106s and they're big and tough to find in crew cab 4x4.

So, now I'm looking into these!

I opted for a LMTV a Stewart and Stevenson M1078. It has the same engine as the top kick but it's cab over engine. If you want to put a 14' box you need to relocate the airbox and the spare tire. But it's 4x4 and has a high GVR. Mine is 17,600 wet with nothing in the bed. I can put 2.5 ton in the bed and tow an additional 5 ton. Just some food for thought.

 

[aernan]

Britboaters. Where did you get your box from and if you don't mind. What would I expect to pay for such an item?

 

[Coachgeo]

I opted for a LMTV a Stewart and Stevenson M1078. It has the same engine as the top kick but it's cab over engine. If you want to put a 14' box you need to relocate the airbox and the spare tire. But it's 4x4 and has a high GVR. Mine is 17,600 wet with nothing in the bed. I can put 2.5 ton in the bed and tow an additional 5 ton. Just some food for thought.

As to relocate box...... wellllllll... you do not "have" to. If you don't obviously you'll just lose some rear clearance angle though.

Also going with LMTV M1078 but have opted to lose clearance. Makes more since since in my case cause am using an ambo box (14.5 long) where wheelwell lines up perfect with ambo box... if I leave the Air cleaner and spare in place. If move them and tuck ambo box forward..... will have to move wheel wells on ambo box AND recreate new air cleaner system AND new tire mount location....... which way over complicates things. If I need I can have a rear lobbed off the box behind back wheels at an angle to gain back the clearance. A labor expense.. but not complicated re-engineering needed to do it.

 

[Britboaters]

I got the box from Complete Bodies in Gay, GA; just south of Atlanta. Cost just over $7,000.
There are lots of body builders at a regional level, so you can probably find one local. You'll need a fairly small shop that's willing to do custom work - in my case install the door I supplied them, and also use my subframe.

Not sure how much a composit box 14' 6" with an attic would cost. My subframe cost me about $450 including mounting bolts, bushings, etc. For a full comparison with a composit box, you'd have to include the cost of insulation and the interior panelling.
Good luck.
Bob

 

[Coachgeo]

I got the box from Complete Bodies in Gay, GA; just south of Atlanta. Cost just over $7,000.
There are lots of body builders at a regional level, so you can probably find one local. You'll need a fairly small shop that's willing to do custom work - in my case install the door I supplied them, and also use my subframe.

Not sure how much a composit box 14' 6" with an attic would cost. My subframe cost me about $450 including mounting bolts, bushings, etc. For a full comparison with a composit box, you'd have to include the cost of insulation and the interior panelling.
Good luck.
Bob

Just for cost comparison..... My 14.5 ambo body cost cost 2 grand before final outfit including subframe (it's built in).... but am accepting idea of not ripping out and redoing inside.... so all cabinets etc already exist. Granted this ambo body is better built than some, it appears.

 

[aernan]

I got the box from Complete Bodies in Gay, GA; just south of Atlanta. Cost just over $7,000.
There are lots of body builders at a regional level, so you can probably find one local. You'll need a fairly small shop that's willing to do custom work - in my case install the door I supplied them, and also use my subframe.

Not sure how much a composit box 14' 6" with an attic would cost. My subframe cost me about $450 including mounting bolts, bushings, etc. For a full comparison with a composit box, you'd have to include the cost of insulation and the interior panelling.
Good luck.
Bob

Thanks for the numbers. I guess I now have some good numbers to decide if I make mine from scratch or have someone fabricate it for me.

For the sub frame. Did you do a 3/4 port torsion style or hard mount?

 

[Britboaters]

The subframe is made from 4" x 2" x 1/4" steel tube.
3 mounting point using Freightliner front spring bushings - massive and not expensive.
2 at the front and one at the rear.