Towing/pulling attachment options. Theory, input please

The axle is held to the frame by suspension. Drive shaft is attached to axle and engine. The driveshaft cannot handle any pulling because of slip yoke. All pulling force from being tied on the axle would be transferred to the frame via suspension.

 

What I mean by that statement is that I don't think the U-bolts are designed to hold that much force by themselves. Bear with me and my HS education. I can say however that I wouldn't hook anything to my axle and go yanking on it without expecting catastrophic failure.

 

Never use a chain to pull someone unstuck. It's dangerous... Get yourself a good quality tow strap.

 

The driveshaft cannot transfer any pulling force to the engine. There is a slip joint. If you lose the aft u-joint, the driveshaft can be removed at the slip joint.
The rear axle is retained by the suspension. All forces acting on the rear axle are transferred to the frame via leaf springs. Ie. Axle twisting due to torque is transferred to the springs. It gives you a nasty, axle-breaking wheel hop.
I'm no ME either, just a hired wrench. Athough, I did go to school to learn my 1 2 3's and my SAE's

 

Hooking up to the differential is a quik and easy way to get it out of the mud.

How one goes about recovering the rest of the vehicle that will be left in the mud becomes the issue...

 

Common sense, use the part designed for pulling, the Receiver Hitch.

 

If you are pulling something with your truck , the rear axle does the actual work. The tires moving. Hooking to the axle would cause 0 stress on suspension frame or body. That idea is correct. (I think people are failing to realise if you hook up to your axle, your axle pulls not the truck, there would be no tension on the driveshaft or leafs added by this)

In 4WD your theory fails, as the front axle does work also and any slippage in the rear would translate from the front axle through components eventually to the rear.

Having your truck pulled by the rear axle, hopefully should be an obvious fail in theory. Your axle does no work and for the most part become a tow hook, except its an unstable one as your suspension will come in to play. When thinking recovery, the best option is to tie into whatever has the most solid mass, which is obviously the frame.



In theory, towing with the rear axle is less stress. A reciever has to go through the frame, through the suspension components, then to the axle with the wheels turning. The advantage of a hitch though that its more distributed between both the axle as well as directly anchored into the majority of the mass of the truck...so a bit of a tradeoff. Momemtum would most definately have an impact on driving, and it would not be fun IMO over 15.

Directly to the axle eliminates such. However, it is pretty impractical and cant imagine how dumb looking it would be trying to rig up an extra long tongue to hook up to your axle.



I was ME major for a couple years and switched majors. These are some major flaws. Momentum and mass...the basic principles.... does your friend work for BP? lol jk

 

you wouldnt have any stress on the frame,

but you would probably snap your axle in two

unless you had a cover plate which would be ripped right off

 

When i was a little younger I pulled an F150 out of a ditch with a tractor and a chain. Ended up bending the rear axel. The next weekend we were replacing it.

 

lol not BP...Yes i am not talking about pulling a stuck truck by its axel...
I am saying that if you hook to the rear diff pumpkin in a secure centered manner...In theory you should have no problems...The axel and rear drivetrain basically is "pushing" all component of the truck...

SO therefore the theory being it would ideally work when using chains or rope liek methods...a solid tounge woudln't work...

You shouldn't snap the diff housing (which is what i am technically refering to)...It is made of some of the strongest materials on a vehicle...

yes but i am more referring to the diff housings and not really tlakign about getting pulled out, More so of doing the pulling...You try to do it way out by the wheel yes you go trouble and angular tension will bend shit....

 

your rear is what drives everything else?? What would pull the rear out from under?

 

You have forgotten the inertia of the tow vehicle in the equation. Force from inertia will pull the axle via suspension. A center pull on axle=bent axle housing. Do the math. Speed x mass(right?)=total kinetic energy. Even if you do a 1MPH pull on a vehicle, it's an awful amout of work to ask of a little axle.
The inertia of the tow vehicle pull on the outsides of the axle, and the inertia of the towed vehicle pull on the center of the axle. You're going to deform or break it

 

Except there is this engine at the end of the propeller shaft straining mightily to twist it. It has to react against something: the motor mounts, transferring it back into the frame and then to the ground through the suspension and tires.

Of course, what that all means from a mechanical systems approach I've no idea....

Which brings on the question...why would you want to change the attach point for the tow anyway? Is there something wrong with it the way it is?