Lightened drive shaft

EvanH · Post by **EvanH** » Mon Jun 29, 2009 12:35 pm

On another thread, I posted some pictures of an oil leak that filled the bell on the center tube with oil. Someone noticed that I have a lightened drive shaft. It is completely gutted, and it does seem quite a bit lighter than I remember. I don't see any signs of balancing weights. For reference, here are some pictures.

I intended this view to be down the length of the now-hollow tube, but you get the idea:

These two show the welding at the end of the shaft. Looks like a neat welding job:

-Evan

undysworld · Post by **undysworld** » Mon Jun 29, 2009 2:35 pm

OK, I'll show my ignorance here. Thanks for posting these pics Evan.

This drive shaft looks like mine too. I was curious about the previous comment which identified it as modified. What made it so obviously different than normal or stock?

I've had my truck since '02, and to my knowledge, the shaft was original equipment, but who knows? John Light once drove my truck and commented that it was fairly vibration-free. So I'm wondering if I've got a stock shaft or a modified one.

What does a bone-stock 712 driveshaft look like?

Thanks in advance for the info.

Paul Underwood

Jim LaGuardia · Post by **Jim LaGuardia** » Mon Jun 29, 2009 2:39 pm

The torque rod and supports have been removed and the end caps welded in place while in a jig.

EvanH · Post by **EvanH** » Mon Jun 29, 2009 3:53 pm

Paul,

The stock driveshaft is a torque rod encased in the outer sleeve. The caps at both ends are not attached to the outer sleeve, only to the torque rod, allowing the torque rod to absorb shock loads from one end of the driveshaft to the other. I presume the function of the driveshaft must be somewhat overkill if we are able to get away with eliminating the innards. The inner rod is/was prone to going out of true, which is the heart of the balance problems with driveshafts.

This picture shows the end view of a stock drive shaft:

And this blurry one shows a balancing weight on a stock driveshaft:

I think the drive shaft is the same for the 710 and 712.

The parts manual gives some hint how complex it really is:

-Evan

David Dunn · Post by **David Dunn** » Mon Jun 29, 2009 4:52 pm

The "lighten drive shaft" is the same setup as used by the 716/18s ...just a matter of getting rid of all the complication.

I wonder if the factory had ever installed any of this type driveshaft in a 710/12, since the gasers were still being made during the early days of the 716/18s ?

ABSOLUTSECURITY · Post by **ABSOLUTSECURITY** » Wed Jul 01, 2009 1:16 am

So a lightened drive shaft is just a stock one with the inner parts removed and ballanced? Basically thats it huh Dave?