Transmission Access

[Kevin Means]

We have another question. We are designing a habitat for our M1083 and we have placed an access panel on the floorboard to gain access to the transmission in case it has to be removed. I can tell by looking at the transmission, that the four large horizontal bolts seem to be the primary transmission mounting bolts, but are there any other bolts that will need to be removed to lower the transmission, that can only be accessed from the top? We're designing the subframe and I don't want to install a crossmember someplace that will block access to any hardware we'll need to get to. Thanks

Kevin

 

[dwlindsey]

I have an M1088 that I am *slowly* getting ready to put a habitat box on. As I proceed removing things, I'm thinking about habitat roof height, which gets me to the transmission height. I'm thinking about putting a transmission hump in the floor. What are you doing about that and what habitat roof height and interior ceiling height are you designing?

 

[Kevin Means]

Hi dwlindsey... Our habitat will be a composite box, which means the chassis and subframe will have to be very rigid to avoid damaging the box. To achieve that rigidity, we're adding a third set of rails (the subframe) on top of the existing set of stacked frame rails. (The subframe is highlighted blue in the image) Since we're adding a third set of rails, our floor will be several inches above the transmission, so we won't have that hump. I don't see anything wrong with having a hump, it's only two inches higher than the second set of OEM rails on our M1083, but we feel we need the added rigidity. Not having to add a third set of rails would have enabled us to have a significantly lower roof, but that's the tradeoff. Our CAD model has our ceiling height at 6' 8" and an overall roof height at 12' 7". That's higher than I was hoping, but not as high as our Class A's 13' roof.

Kevin

 

[dwlindsey]

Thanks Kevin:

I don't recognize the stacked rails on our M1088. We've got one rail. Some sections have a second slightly smaller rail inside and in some sections there's a plate on the outside.

I'd like to keep the top of the solar panels below 12' if I can. There's a 12 foot high garage door on my garage . . .

I've got a big auxiliary transmission cooler to remove and then another section of platform to remove. the platform is part of the larger platform deck that the team would stand on when hooking up the electric and air to the trailer on the 5th wheel plate.

The fifth wheel plate is loose, just a couple of loose bolts holding it on while I drive it to the scrap yard.

When I get that stuff off, maybe this week, I'll be able to see the frame and transmission more clearly and maybe start to make a plan.

We'll definitely have a subframe, or it's equivalent in a steel floor structure. A transmission hump will make the interior floor more complicated, but the roof height lower . . .

I'm still thinking of a welded steel frame for the habitat. My colleague who does CAD design on SolidWorks is thinking aluminum angle for the walls and ceiling and composite panels that get glued onto the angle from inside. I haven't signed off on that idea yet.

I'm months away from doing the habitat build, probably early next year I'll get it started

Dwight

 

[MugOfPaul]

If the clearance needed will be just a few inches, maybe consider a raised floor just in that front section. It's pretty common to see, gives you some extra space for storage or infrastructure, and easier to work around than an awkward hump in the center.

Thanks Kevin:

I don't recognize the stacked rails on our M1088. We've got one rail. Some sections have a second slightly smaller rail inside and in some sections there's a plate on the outside.

I'd like to keep the top of the solar panels below 12' if I can. There's a 12 foot high garage door on my garage . . .

I've got a big auxiliary transmission cooler to remove and then another section of platform to remove. the platform is part of the larger platform deck that the team would stand on when hooking up the electric and air to the trailer on the 5th wheel plate.

The fifth wheel plate is loose, just a couple of loose bolts holding it on while I drive it to the scrap yard.

When I get that stuff off, maybe this week, I'll be able to see the frame and transmission more clearly and maybe start to make a plan.

We'll definitely have a subframe, or it's equivalent in a steel floor structure. A transmission hump will make the interior floor more complicated, but the roof height lower . . .

I'm still thinking of a welded steel frame for the habitat. My colleague who does CAD design on SolidWorks is thinking aluminum angle for the walls and ceiling and composite panels that get glued onto the angle from inside. I haven't signed off on that idea yet.

I'm months away from doing the habitat build, probably early next year I'll get it started

Dwight

 

[dwlindsey]

Yes, we're thinking about that. Our first thought was to put the bathroom in front, toilet room on one side, shower on the other, pass through in the middle.

Over the last couple of days, we've been considering putting a dinette booth in front, with the pass through either above the back of the booth, or beside it if we put the booth on one side along the long axis of the truck. The raised floor probably works better with the dinette than it would with the shower (we're tall).

It's all about using the space as efficiently as possible and doing our best to make it comfortable to live in and drive.

We're at least 6 months off before we need to decide what the interior layout is.

Dwight

 

[GeneralDisorder]

Here's an idea. Copy what the military did on the 1079/1087 and have none of these issues. No floor hump. No torsion problems. No height problems. Plus it's been real world tested by the largest military in the solar system for 30+ years.

 

[dwlindsey]

Where do I find details on that? I'm still a noob here and about these trucks

 

[GeneralDisorder]

Where do I find details on that? I'm still a noob here and about these trucks

Search. Lookup how to use Google to search within web sites like this FMTV forum.

"M1079 van mounting", "M1079 pocketed springs", etc. Google image search, etc.

Basically the habitat itself is ridgid enough to be air lifted on it's own from its four rings on the top corners. It is mounted to the truck with pocketed springs on the front and a loosely bolted connection at the back with rubber isolation pads that are attached on the box and the frame with bolts and loose fittings castle nuts - such that the truck frame can twist away from the box and the two front pocketed springs will allow the box and frame to separate by several inches.

The whole system is extremely simple with basically zero moving parts. It's all heavy steel with nothing to really break or wear out. Hell even the rubber pads are holding up just fine 17 years in......

 

[dwlindsey]

I do know how to use google . . .

 

[GeneralDisorder]

Hell it's my daily anyway so here ya go:

Front:



Rear:

 

[GeneralDisorder]

All you really need to accomplish this is a ridgid floor pan for the habitat that duplicates the mini-frame that is bolted directly to the floor of the M1079 van box. It's made of 3" x 1/4" wall "C" channel. As long as the floor is capable of ridgidly supporting the box when it lifts one corner off the front of the frame you're good to build the rest of the habitat out of plastic or paper mache or whatever sillyness. I prefer METAL in all cases but that is just a bridge too far for most people in terms of labor.