HMMWV questions

[ccf460]

I am thinking about brokering a deal for a HMMMV frame/suspension set. My intent would be a 12 valve 5.9 cummins/NV4500 powered truck very similar to the CC surplus truck that was built last year (already have the motor/trans), but I have a few questions:

1. I see the towing capacity of a M998 rated at approx. 3500 lbs., what is the limiting factor? Is it the engine/trans combo, or braking, or suspension? I am not wanting to build a max tow rig, but do occasionally want to tow 10,000 lbs., and frequently tow 5,000 lbs. on an electric braked trailer with an ideal tongue weight under 750 lbs.

2. How hard is it to find a decent body? Price?

3. How are these to live with on a daily basis?

4. I am thinking a painless wiring harness in 12 volts, and off the shelf gauge set. If starting with a stripped body,how much will it cost to finish the body with standard items in the steering,braking, interior trim (ha ha) ,that will be missing? (not counting doors and top, very wide range of price and options)

 

[Blackmagic94]

150 hp is not going to work well at towing 10,000 lbs and living long.

 

[CBR Metalworks]

150 hp is not going to work well at towing 10,000 lbs and living long.

150hp? Did you miss the statement of him using a 6bt cummins? I know stock they are about 160hp, but the 6bt has been put in a gazillion Dodge trucks, all made to tow well over 10k lbs...

 

[Blackmagic94]

Towing is also more then power

frame strength
braking power
brake resistantance to fading
transmission
thermal control
gearing

 

[CBR Metalworks]

Will also have all 12k parts on what he is getting. I think the frame is a civilian frame, so not sure if it is considered 12k or 10k.

I don't know crap when it comes to towing with a HMMWV, but you will have plenty of motor to do the job, not sure I would try 10k lbs unless you had good trailer brakes and were not towing far, but even then it would probably be too much. I towed my 8k lb skid steer on a light 6x12 trailer behind my M1009, let's just say it was overloaded! I only had to get it a couple miles on back roads so I was able to drive very slow (~30mph or less)

 

[patracy]

Well they do pull these trailers with the HMMWV platform:

http://www.gichner.us/fht.html

Gichner's S-788 FHT is a fifth-wheel variant, high mobility, tactical trailer equipped with a removable light weight multipurpose shelter.

The shelter is designed in accordance to military specification MIL-S-44408 and meets ASTM-PS-138 andASTM-E-2377 performance specifications. This shelter platform serves as the US Military's most widely used light weight multipurpose shelter (LMS) and can also be mounted on utility variants of the High Mobility Multipurpose Wheeled Vehicle (HMMWV). The shelter is constructed of light weight aluminum bonded panels with Nomex honeycomb core or closed cell rigid foam core.

Gichner offers six variants of these LMS shelter types each weighing less than 650lbs and providing a minimum of 3,300lbs of payload capacity. The shelter is mounted to the trailer via four shock absorbing mounting provisions and can be removed by appropriate overhead sling.

The trailer is designed for high mobility applications suitable for missions required of HMMWVs. The trailer is constructed of a combination of aircraft grade aluminum and HSLA steel, equipped with an air-ride suspension, electronic micro-processing hydraulic breaking system, manual stabilizing/leveling jack, and fifth-wheel attachment suitable for transporting by HMMWV, militarized medium tactical vehicle, or commercial medium duty truck.

[h=3]Specifications - With S-788 type III variant Shelter[/h] Maximum Vehicle Weight:
7,000 lbs

Curbside Weight:
2,750 lbs (Trailer weight: 2,100 lbs / Shelter weight: 650 lbs)

Maximum Payload Capacity:
Trailer: 4,250 lbs
Shelter: 3,300 lbs

Construction:
Trailer: Unitized Design of Aircraft Grade Aluminum & HSLA Steel
Shelter: Insulated Bonded Aluminum Panels

Overall Length:
197 inches


Overall Width:
85 inches

Shelter Interior Length:
99 - 1/2 inches

Shelter Interior Width:
81 - 1/2 inches

Shelter Interior Height:
64 - 1/2 inches

Overall Height:
106 - 3/4 inches

Trailer Deck Height:
36 inches


Track Width:
72 - 1/2 inches

Ground Clearance:
16 - 1/5 inches

King Pin Height:
99 - 1/2 inches

Features:
• (4) Folding, Side Wall Roof Access Steps & (1) Roof Hand Hold
• Stabilizer Leveling Jack with Optional Shelter Level Indicators
• Exterior, Rear Door Mounted Access Ladder
• Optional Generator Tunnel, Roof Mounted Escape Hatch, and CB Purge Valve

So that's 7K lbs max weight. But it's a 5th wheel setup.

 

[ccf460]

That is some good info. I am hoping someone else in this forum has actually done some towing with theirs. I am new to studying these things, but was wondering about getting the heavy rear springs they use on something like an ambulance version? I have no doubt the brakes are a little under powered for this kind of weight, but with care and a well functioning trailer brake setup it should work ( my cummins 2500 actually stopped better in most situations when I had my brake controller set just right). My MAIN concern is towing big weight with an IFS rear suspension?

 

[NDT]

I am no expert but I think the limitation in the powertrain is the differentials. As the weight of the trucks has gotten more and more with uparmor, AMG had to progressively add oil capacity, cooling fins to the cover, and a remote cooling circuit. And this is just to survive 15,000 lbs GVW, not talking about 30,000? GCWR you are thinking about. The differentials are a far cry from a Dana 70, even given the 2:1 final drive ratio in the geared hubs.

 

[ccf460]

If I am correct a 998 4 man truck weighs in at 5200 lbs. with a 6.2/auto set up. I am assuming the 6BT/NV4500 will add 400 lbs., add some bumpers/ add ons / etc... and maybe a 6000 lb. rig . Add 10,000 lbs. for a total of 16000 lbs. Also, this is an occasional load (like maybe 4 times a year for a 25 to 50 mile round trip). It will, 90% of the time, be running empty.

 

[cbear]

I've seen an H1 tow a 30+ foot cigarette boat on I-95. Was it safe? I have no idea.

 

[Retiredwarhorses]

This al depends on the what your drive train is set up for...2:56, 2:73 or 3:08 gears, what motor and trans?
Next is braking, all the new trucks are 12k halfshafts and larger rotors, either solid or vented, the newest models have the wilewood brake setup with the Shepard steering box, ultra HD pitman and idler arm, you must have the correct left free rail for this application.

personally, I have driven all of them, 6.2, 6.5, 6.5TD, Duramax, cummins and Gas motors....hands down, the Duramax just impressed the **** out me...and man, what a freaking Rocket ship...as a matter of fact, so much horse and torque, we were blowing out rear stub axles in the Diffs, this is why AM General took 2 year to bring the 2006 H1 to market...they ultimately had to detune the crap out the motor to stop it from grenading certain components...stub axles was one of them, the trucks I have driven were all conversions with turbo, intercooled, chipped and 4in stainless exhaust as well as 12K halfshaft and brake setup.

AFAICl the frame will handle 10k, as long as you have the Heavy rear bumper with Artillery towing MWO applied, you should be fine, that and all grade 8 hardware.

Rear springs? Most everything now uses the variable rate spring in the rear with the casted spring purch.
there are other HD springs though, this is due to all the various applications the HMMWV is setup for, with and without armor packages, shelter setups, AD arty setup, maint shelters....the list goes on.

if you want the HD frame? Each frame rail is now 3 pieces, the 2 ends and the middle, as well it is galvanized. It would be the ECV, enhanced capacity vehicle....anything else is just the standard frame setup.

 

[blhar15]

To address your question on finding a body, those are pretty hard to come by these days, at least one that does not need alot of work. They are also very high priced. The last one I saw was $10,000 and in decent shape.

I am thinking about brokering a deal for a HMMMV frame/suspension set. My intent would be a 12 valve 5.9 cummins/NV4500 powered truck very similar to the CC surplus truck that was built last year (already have the motor/trans), but I have a few questions:

1. I see the towing capacity of a M998 rated at approx. 3500 lbs., what is the limiting factor? Is it the engine/trans combo, or braking, or suspension? I am not wanting to build a max tow rig, but do occasionally want to tow 10,000 lbs., and frequently tow 5,000 lbs. on an electric braked trailer with an ideal tongue weight under 750 lbs.

2. How hard is it to find a decent body? Price?

3. How are these to live with on a daily basis?

4. I am thinking a painless wiring harness in 12 volts, and off the shelf gauge set. If starting with a stripped body,how much will it cost to finish the body with standard items in the steering,braking, interior trim (ha ha) ,that will be missing? (not counting doors and top, very wide range of price and options)

 

[TedG]

ccf460,

Late version tubs new from amg without any extra pieces will run around 18K plus shipping. That is tub only.
The rev frame rails for ecv that hummerguy mentions are around 5k per set, rails only, new from amg.

pm me for another hmmwv tub option if you want.

Ted