I broke the passanger side half shaft in my c3 , the car would not move?? this is a posi car it should move on one shaft?/
Other than having to buy a new half shaft what should I look for and where do I buy a stronger than oem half shaft,
Thanks
Tim

 

Unless when you broke the half shaft ...the ring and pinion gear in the differential had teeth broken off of them and are now lodged in the area where they mesh and the differential is locked up also. Post what year this car is, auto or manual. C3 is to vague of a term. There are differnt types of half shafts in the C3 era. Post a picture if you can..it is always helpful.
"DUB"

 

My question is , will the car move with only one shaft in place?
When I tried to get it off the road the speedo showed mph but the car was not moving

 

Your posi unit is probably smoked also. Not from the broken half shaft but from years of use. You are just spinning the internals of the posi so the driveshaft is turning but you are spinning the half shaft that is broke. If the posi was new and tight yo uwould probably be able to at least move it. I would not drive it this way though.

 

I am looking for parts , ecklers is asking if it is a 4 speed or automatic? what is the differance? It was an auto car from GM but has been changed to a 4 speed.
lastly the diff has a red tag stating limed slip is this posi or not?
Thank u all
rim

 

I just broke a greasable joint, last sept. Hitting 2nd @ 5300. Left side outer. No damage to the Diff. I tried to back in the garage after removal of the shaft, Not happenin. Works fine now. I have learned that a TH350C
with a B&M kit makes very harsh shifts mainly because of the near 40 lb. Torque Converter. Just my thoughts.

 

It is an auto car then

Limited slip = Posi

 

Although the end results are similar, limited slip and positraction work differently.

Posi exerts a constant preset force on the clutches.

Limited slip exerts a force on the clutches when a load is applied to the pinion gear. This force is directly proportional to the applied load. With a broken half shaft, no load can be applied because the stub shaft free wheels.

At least that's the way I understand it.

 

The half shaft also acts as the upper link of the rear suspension supporting the rear wheel. Don't try to drive the car.

 

"Posi" is an abbreviation for "Posi-traction," the name GM uses for its limited slip differential. Limited slip is a generic reference to a clutch-type torque-biasing differential. There is no difference in operation since you are talking about the exact same thing. If you're referring to the preload spring you see in most limited slip (Posi) housings, that is just a mechanical feature and has nothing at all to do with a distinction between the two -of which there is none.

If you break an axle (or halfshaft) in a limited slip differential, it is not likely to move unless you have exceptionally high preload on the side gears. An unloaded side gear will not apply load on the clutch mechanism and will send all the work to the axle of least resistance.

This is how a limited slip (or Posi) works in biasing torque: The pinion gears (often referred to as spider gears) drive the side gears. Between the side gears and the differential case are clutch packs (or a cone in some designs) consisting of frictions and steels. One part of the pack is locked into the differential case. The other part of the pack floats in the assembly. When the pinion gears react to load (either resistance from the axle or input from the driveshaft), they move the side gears away from the pinions and put a clamping force on the clutch pack, which causes the side gear to friction lock to the differential case.

The biasing occurs where the forces on the axles are not equal. When negotiating a tight turn, the inside wheel has to turn slower than the outside. In this case, the outside tire has to unlock to allow the differential to function. Most of the drivetrain power is being applied to the inside tire. It's certainly possible to "overcome" the biasing in this example by applying input power that exceeds the torque being applied by the axle.

Another example is when trying to get the car rolling when one tire is on ice, the other on dry pavement. While it would seem this to be the perfect environment to test the affects of a limited slip, it frequently does not work out that way. It's entirely possible for the tire on ice to spin, while the tire on dry pavement does nothing. This, again, has to do with how a differential works. A differential is designed so both axles (and tires) do equal work. While it's mostly assured that an open differential will just spin the tire on ice and the car will go nowhere, you again can have the same result with a limited slip. If there is no reaction on the axles to torque input, there is nothing to force the sidegears to compress the clutch assembly. In the ice/dry scenario, the solution is to apply the emergency brake (not full, but nearly full). While this may seem counter-intuitive, the loading you are applying to the axles will allow the clutch packs to compress and allow the tire on dry pavement to drive.

So in the case of a broken axle, you may have some luck in being able to get the car moving by applying some emergency brake, but I wouldn't count on this getting you very far down the road. You're stil going to have one unloaded axle and anytime the vehicle see some load, such as going up even a modest hill, it's likely to send all the work to the non-driving axle.

 

Very nice explanation, except that the half shaft has snapped so applying the parking brake will not increase the load on that side of the diff.

As mentioned above the half shaft is also a load bearing suspension member so trying to move the car is either futile or dangerous.

 

I tore up the same half shaft on my 4-speed 80 a couple years ago (though I still say the burnout was worth it). It was the passenger side half shaft, and when the inside (differential side) u joint broke it tore up that side of the half shaft. Like you said, the car wouldn't drive anymore. But it was only a couple blocks from my house, so I had a couple of friends push it back home for me. As the car rolled, the shaft rotated and banged on the cross member, but that short distance didn't cause any damage.

My advice: don't cheap out on your new u-joints. If you're driving the car hard, the "heavy duty" ones from Checker or AutoZone won't last you very long.
For the half shaft, I replaced mine with another oem half shaft a friend had, and it's been great.

Good luck!