ZZ4 crate, mild 700r4, rebuilt 10 bolt with 3.73's, towing capacity?

[english_5064]

Hi Guys,

I'm looking into buying a travel trailer with a dry weight of 7500lbs and about 2000lbs of storage capacity bringing the GVWR to about 9500lbs. I believe the hitch weight is about 1000lbs. I'm wondering if anyone has a similar setup to what I have and has towed this much weight before safely.

The truck is a K10 4x4 long wheel base and has a ZZ4 crate motor. it dyno'd 260hp and 370ft/lbs of torque at the wheels.
I had a 700R4 mildly built with a shiftkit and a corvette servo.
I rebuilt the 10 bolt rear with 3.73 gears, 28 spline axles and a Eaton tru trac posi unit.

I currently tow a 6000lb GVWR trailer around with no issue in drive (not over drive lol), but 9500lbs is starting to push it in my opinion. I need to look into what hitch is installed on the truck...I think its a class IV or V...

Does anyone know if I could tow this safely/legally? I do have a prodigy brake controller installed in the truck, so I don't think braking will be an issue. I go camping a lot in the mountain region and hills will definitely be a factor.

Thanks in advance for any advice.

[werewolfx13]

I wouldn't hesitate to pull a 9500 lb trailer with brakes with my 83 c10, but I don't really expect steep hills. One thing I would look at, is a little thickening of the frame rails where your hitch is bolted. Mine has 3/8" steel plates welded to the frame (top and bottom of the bottom of the rail) where the hitch bolts are. The plates are custom fit to maximize contact, and I've bolted flat braces down the side of the hitch and side of the frame.

A travel trailer of that size, I would expect to use a sway control kit and a weight distributing hitch for best handling. Truck brake upgrades would be beneficial for mountain driving.  Also, depending on state, look at your licensed weight rating for your truck. My 83 is licensed for 12000 lbs, and I've tweaked that limit a little, my '76 k20 is licensed for 18,000, and I expect I'll push that limit once the truck is completely outfitted and pulling a goose neck.

[slammed79]

Helper bags would also help if you're lifted at all. Lifts in my experience sacrifice towing capacity.

[bake74]

      The question is not whether it can tow it, you should be asking can it handle it.  First off the 10 bolt is under designed to handle that much weight.  Second, the 1/2 ton suspension itself is not rated for that much.
      You can use a equalizer tow hitch to help with the sway, and as slammed79 said air bags for the weight, this should keep you going down the road straight and not be all over the road.  But that does nothing for wear and tear on the 10 bolt and 1/2 ton suspension.  I have done this with my 74 k10 before and it is not pretty.  Horsepower can get you moving down the road, but remember you still have 1/2 ton suspension and brakes. (adding trailer brakes to take some of the load of your truck would be a must).
     Unfortunately you can not just upgrade your rear axle and not the front axle (different lugs count), but you could upgrade your springs in the rear and wait to see how your axle does and if it brakes replace the axles and parts with beefier componets.
     I have towed all kinds of things before in my life, and it is not horsepower you should be concerned with, it is the ability of the tow vehicle to keep the loaded trailer going down the road in a straight line and the tow vehicle being able to handle the towed trailer.  The worst situation you can get into is where the towed trailer is handling or pushing the tow vehicle.

[78 Chevyrado]

4x4's can tow LESS than 2wds.  9500lbs sounds like a lot for a long trip. 

My 3/4 ton is rated for 12k  towing but it has the heaviest duty everything. including a 14 bolt rear end and 13" brakes.  Lighter-duty 3/4 tons couldn't tow the full 12k.

I'd be Real Leary of a 10 bolt with that kind of load if the roads aren't pretty flat and level.

If you're easy on it, it will work with proper trailer brakes, but if you get on it especially in hilly places, Expect those spider gears to bust, which will break the tranny when they go.

This is from my 78 owners manual.  The 1/2 tons of the time had 12 bolt rears which are stonger than 10 bolts of the later trucks.


Note in this pic.  the say 8000 lbs limit for c10's, is for c10's with the heaviest duty suspension which was basically 3/4 ton suspension.

K-10 is 6500lbs.  thats for the heaviest duty K10 available.  if you dont have the heaviest duty suspension/brakes, your limit is less.

Notice a C20 can tow 12k but a k30 can only tow 7k.