Upgrading a CUCV's max towing capacity?

LanceRobson

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If a large transmission cooler were added to an M1008 and speeds were kept to 50-55 MPH, does anyone have a guess what would be a reasonable max towed load with a fifth wheel hitch?

I have a combo fifth wheel and gooseneck hitch in my F-350 that drops onto low profile mounting plates that are, in turn, bolted through the truck floor to the frame. It lets you move the hitch from one truck to another and lets you have an unobstructed bed when the hitch is out.

I know I'm not going to get anywhere near 20K on it or drag our 36' fifth wheel but does 10-12K sound reasonable with a good brake controller?

Our 15 year old is looking for something to haul the 1922 Oilpull tractor to more parades. (Yeah, I know....It's the wrong kind of big green toy)

Lance
 

maritimer

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RE: Upgrading a CUCV

with those weights you might want to look at the turbo package offered by banks other wise you'll be accelerating liek a turtle.
i regularly hook up to 6-8K dead wea=ight on the issued pintle mount of my m1009 *blazer body* without issues *and with a good brake system and a proper fithwheel hitch i cant see why your required weights would be a safety issue but the 6.2 non turbo is gonna struggle to get 10-15k moving let alone up hill
 

AJMBLAZER

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RE: Upgrading a CUCV

10-12k is still a lot to tow. These trucks are 22 or so years old. In those days 7k was considered a hefty towed amount and now half tons tow more than that. Remember that not just the engine is at play here. The chassis wasn't designed/built to tow that much and neither were the brakes. The engine, even with a turbo, definitely wasn't.

Not trying to rain on any parades here but along with getting it moving he has to be able to safely maintain speed and stop that weight.
 

11Echo

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In 1986 a K20 Suburban with 6.2, automatic trans, and 4.10's was rated at 12,000 GCW. This is the only printed matter I can find now. My loaded civilian K20 Suburban 5.7 powered with 40 gal fuel weighed 5400. My CUCV weighs in just under 6000. While not recommending what you do, I can tell you that them old trucks are tough. Hauling loads like in this pic were common for me and others.
 

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Recovry4x4

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11Echo said:
In 1986 a K20 Suburban with 6.2, automatic trans, and 4.10's was rated at 12,000 GCW.
Thats GCW minus the nearly 7000 the truck weighs brings it back to about 5000#
 

LanceRobson

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As an update:

The whole idea is to get a light to medium duty rig for the youngster to move stuff without too much fuss. By the way, he and his buddies have had a fire going in a 1908 Waterloo 16 HP steam traction engine most of the day to pressure check it for leaks prior to making a tour of the local ponds. You can hear the whistle for about 2 miles. Gotta love farm kids!

I appreciate all the input. If the M1008 ever tows anything this heavy, it will be a couple times a year, to local parades. For longer distances or heavier loads we've got other tow rigs.

Here's my thoughts (I should have said all this up front)

This is a rural area, it's not too hilly, and I'm not too worried about acceleration. It'd never need to merge at Interstate speeds with this load.

The braking weight would be handled by the brake controller. I've an extra one rated to 27K and 3 axles.

The tractor weighs 6600#, the gooseneck is 3800# (with winch and chains). The hitch is 140#. At an all up trailer weight of about 10-11K#,he tongue weight would likely be 1500-1600#.

The limiting factor in all this seems to be transmission heat.

Certainly the suspension, tires and frame can handle the load. The tranny can pull it.

The installation kit that lets you move the combo fifth wheel and gooseneck hitch between vehicles is (last time I bought one) $129. I guess I'll order one and see if the truck will move the weight OK and then go from there.

Lance
 

11Echo

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Hi Lance. I have never burned up a turbo 400 in any of my similarly equipped GM pickups. I did order all the factory tranny/engine oil coolers when buying new trucks. A M1008 with 4.56's will definitely step off the line better than a 3.08 equipped M1009. The truck above was equipped with 4.10 gears. I hauled that trailer with 450 bales of hay many times. I used to haul a camper and trailer with 6 horses in the back with no problem. With proper trailer brakes you should not have any problems with stopping.
 

Refalgren

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hehe...

Im currently PCSing between duty stations, but am doing a TDY-enroute. I recently loaded up both my M1008 and towed 14ft flatbed trailer and drove it from Ft. Lewis, WA to Topeka, KS. distance of about 2,000 miles. I estimate (still have to weigh it) the weight is around 13,000lbs combined truck/trailer weight. While driving, even a 5* grade had me slowing to a 30mph crawl. I was shifting to 2nd gear on some of those hills with even the big rigs passing me (and they can get slow) :p

Can you say "Overloaded" :D
 

citizensoldier

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The downfall here is in the 6.2 motor.. That old truck frame,trans, gear combo is much stronger than most frames produced after.. Just two cents here... Many guys would put a in box camper and pull a tandem axle flatbed with another truck on it.. When they switched to the 89 to 99 style the frames could not hold it and would brake or twist. . I am not sure about the real new stuff after 99 I quit looking.. turned truck into fancy grocery getters and price me blind.. LOL..
This info is straight from my best friends sister. She is the head of the GM truck complaint department.. Here is a quote from her after the Durimax came out.... "We now have a motor we just need to build a good truck to put around it"..
 

randyscycle

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Pulling weight never bothers me nearly as much as stopping it. Even with really good trailer brakes, most truck systems of years gone by were marginal at best. When there was nothing better 25 years ago, we didn't know any better and routinely pushed our brakes to the limit.

I'd go for something a bit more modern if it were me. At least an axle and brake upgrade to compensate for the extra load.
 

citizensoldier

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A good set of electric trailer brakes work fine or even srrge brakes.. We used to pull a 23' off shore racer with a 89 Cadilac Eldarodo and surge brakes... Just had to use good old common sense.. Everything old was not marginal in my opinion.. They did well pulling and stopping loads for me they just rusted away or they would still be here pulling loads today..
 

Mercunimog404

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The downfall here is in the 6.2 motor.. That old truck frame,trans, gear combo is much stronger than most frames produced after.. Just two cents here... Many guys would put a in box camper and pull a tandem axle flatbed with another truck on it.. When they switched to the 89 to 99 style the frames could not hold it and would brake or twist. . I am not sure about the real new stuff after 99 I quit looking.. turned truck into fancy grocery getters and price me blind.. LOL..
This info is straight from my best friends sister. She is the head of the GM truck complaint department.. Here is a quote from her after the Durimax came out.... "We now have a motor we just need to build a good truck to put around it"..
These are not built better than a modern truck.
 

jwaller

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You'd be wise to get several of the biggest tranny coolers you can get. B&m race coolers are 28k rated and have 1/2" npt fittings. Remember the torque converters in the TH400 are non lock up so every second they are slipping and the temps will only continue to rise until you let off the pedal and that's not going to happen with those kinds of weights.
 

Skinny

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The old K30 chassis is still a big floppy C channel design but the newer trucks can't compare...they are junk. The only thing going for them is updated engine and transmission technology. Yes, makes more power but suck to work on. The 5/4 ton CUCV trucks would be great higher capacity work rigs if they had a Cummins and an NV4500. The low horse 6.2 combined with the bulletproof but slug TH400 is not a good combination for anything other than reliability and simplicity.
 

Mercunimog404

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The old K30 chassis is still a big floppy C channel design but the newer trucks can't compare...they are junk. The only thing going for them is updated engine and transmission technology. Yes, makes more power but suck to work on. The 5/4 ton CUCV trucks would be great higher capacity work rigs if they had a Cummins and an NV4500. The low horse 6.2 combined with the bulletproof but slug TH400 is not a good combination for anything other than reliability and simplicity.
They're not junk. What's junk about them? You just basically replaced everything in the Cucv. You said the frame was floppy, upgrade the tranny. What's left? The np208 in the 1008 isn't better than newer tcases. The axles now are huge compared to the 14bolt used in the Cucv. The new trucks can carry a crap ton of weight. The only thing a Cucv has is the Detroit locker.

Edit: and compares to a model t. Your Cucv is lite years more complex and difficult to work on. With the sweet electrical system it has. 4 wheel drive. Locker and on and on. :)
 
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Skinny

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The NP208 isn't great but at least it's cheap to run and does the job. Any new parts that needs to be replaced on the newer case (pump issues, actuators, etc.) you can buy a pallet of NP208's.

Have you actually used a late model truck for work? A 2500 HD with a plow is just a joke...keep stock of frontend parts. Let's not get into the "remove the cab to change Duramax headgaskets" conversation. Everything an owner wants...expensive to buy and own. The 24v system is not difficult to fix and it works just fine if you understand electricity.

The CUCV is a great workhorse, but it won't pull the same as a new 1 ton diesel. It also won't cost $60k new and take 3 hours to change a drive belt.
 
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