M929A2 Driveline Question

[Vermonster]

Long story. On the way home from work today, loaded, I rounded a corner at approx 5mph, heard a "Clunk", like a rock rolling against my headboard. 2 miles down the road ALL of my Right Rear Wheel Studs Sheared Off, deflating the tire, (tore the valve stem off) , and the wheel almost come off. Thought I lost a wheel bearing and the wheel locked up. It didn't. Hub was only luke warm, same with the Differential, and Brake Drum. Axle turns Free, along with opposing wheel. Called a Wrecker. When Truck was lifted in the air. Front Axle turns Free, Rear Axle Turns Free, BUT..... They Don't Turn Together. Question: Do these Truck Rear Ends BOTH Drive All The Time or Do They Have Some Kind Of Internal Power Devider Locking System that only engauges in a Slip Situation. Like are My Rear Drive Wheels in 4 Wheel Drive All The Time or Not? Civilian Trucks got a little Air Switch to lock the Power Devider to Drive The Rear Axle. Trying to figure what broke all my wheels studs. Rear wheel Never Locked Up. Outside of that Clunk, nothing was out of the ordinary. I don't get it.

 

[G744]

They are driven together by the intermediate drive shaft, AKA they are constantly locked into "4-wheel drive".

It would take a very unusual event to shear off 10 wheel studs. Were you running duals or singles? Not that that really matters in your case.

Offhand, I'd say you had a hard failure in the double-reduction gears in the axle, tho that usually snaps an axle.

Your problem is a very interesting thing. When you find out what happened, don't forget to post what it was here.

 

[Vermonster]

They are driven together by the intermediate drive shaft, AKA they are constantly locked into "4-wheel drive".

It would take a very unusual event to shear off 10 wheel studs. Were you running duals or singles? Not that that really matters in your case.

Offhand, I'd say you had a hard failure in the double-reduction gears in the axle, tho that usually snaps an axle.

Your problem is a very interesting thing. When you find out what happened, don't forget to post what it was here.

Running Singles. Axles seem.... to be fine as opposings wheeels spin. Driveshaft from front differential to rear dif Does Not Spin with all wheels off the ground. Gonna Drain Front Diff and look for Chunks. I will post as it unravels. Long as I've had it, it has not been abused. It's been worked...., but not Beat. I drove 10 Ton in the Army and 50 yrs Civilian more or less and this is the damndest thing I ever saw. Truck would "Hop" occasionally like a Tire was out of round but would come out of it once they warmed up.

 

[simp5782]

Vibration is the main cause of shearing lug studs. It's happened to me a good any times. I've even broke a wheel face.

May check your bearing play in that hub.

2nd reason is cause some moron put left hand studs on the right hand side.... yes I've seen 3 trucks come from the auctions with the backwards studs.

Not sure how long you have had the truck to know if you have had the tires off before or not

Chain it up and drive it home.

 

[Vermonster]

Running Singles. Axles seem.... to be fine as opposings wheeels spin. Driveshaft from front differential to rear dif Does Not Spin with all wheels off the ground. Gonna Drain Front Diff and look for Chunks. I will post as it unravels. Long as I've had it, it has not been abused. It's been worked...., but not Beat. I drove 10 Ton in the Army and 50 yrs Civilian more or less and this is the damndest thing I ever saw. Truck would "Hop" occasionally like a Tire was out of round but would come out of it once they warmed up.

Vibration is the main cause of shearing lug studs. It's happened to me a good any times. I've even broke a wheel face.

May check your bearing play in that hub.

2nd reason is cause some moron put left hand studs on the right hand side.... yes I've seen 3 trucks come from the auctions with the backwards studs.

Not sure how long you have had the truck to know if you have had the tires off before or not

Chain it up and drive it home.

Thanks. I've had the truck about a year. Never had a wheel off of it. At certain speeds, and RPM's I got a pretty good vibration in the Driveline somewhere almost like a heavy Rattle. Thought something was loose on the frame right under the cab. Checked everything I could see. Drained the Transfer Case and no metal came out of it. Fresh Oil and the Rattle is still there although not as bad. Maybe totally unrelated. I don't know.

Wheel studs. Honestly I don't know which way the Thread goes at this point. It was dark and in all the excitement I just wanted the thing home. It's at the bottom of my driveway and I was going to dump the load, chain up the axle and try and drive it up to my garage.
A friend and long time Truck and Equipment Mechanic asked about if the lug nuts were properly Torqued. I don't know that either. Never touched them. I don't know the Torque Spec.
My Wheel is pretty much trash, but luckily the truck came with 4 extra rear wheels, New Tires, and an extra front wheel and tire all mounted.
I get it up here and dive into it, I'll know more. Gonna be a learning experience.

 

[simp5782]

Thanks. I've had the truck about a year. Never had a wheel off of it. At certain speeds, and RPM's I got a pretty good vibration in the Driveline somewhere almost like a heavy Rattle. Thought something was loose on the frame right under the cab. Checked everything I could see. Drained the Transfer Case and no metal came out of it. Fresh Oil and the Rattle is still there although not as bad. Maybe totally unrelated. I don't know.

Wheel studs. Honestly I don't know which way the Thread goes at this point. It was dark and in all the excitement I just wanted the thing home. It's at the bottom of my driveway and I was going to dump the load, chain up the axle and try and drive it up to my garage.
A friend and long time Truck and Equipment Mechanic asked about if the lug nuts were properly Torqued. I don't know that either. Never touched them. I don't know the Torque Spec.
My Wheel is pretty much trash, but luckily the truck came with 4 extra rear wheels, New Tires, and an extra front wheel and tire all mounted.
I get it up here and dive into it, I'll know more. Gonna be a learning experience.

A2 Trucks have a driveline vibration dampener. I've only seen a few of them go bad but its where I would start.

 

[G744]

Lugnut torque is something shops seem to think is proper when they stall out a 1" air wrench on every one. Then, if one has a flat, you'll never get them loose with hand tools. Plus, that will eventually dish out the beveled hole in the wheels, too.

In many, many miles in tacticals, I've never had a wheel come loose when the nuts were run up tight with a 24" bar & socket by hand. That comes out to a bit more than 300 ft/lbs.

 

[Vermonster]

Lugnut torque is something shops seem to think is proper when they stall out a 1" air wrench on every one. Then, if one has a flat, you'll never get them loose with hand tools. Plus, that will eventually dish out the beveled hole in the wheels, too.

In many, many miles in tacticals, I've never had a wheel come loose when the nuts were run up tight with a 24" bar & socket by hand. That comes out to a bit more than 300 ft/lbs.

Oh I agree on the overzealous use of air impacts. Is approx 300 lbs. the correct torque for wheel studs?

 

[Vermonster]

A2 Trucks have a driveline vibration dampener. I've only seen a few of them go bad but its where I would start.

Thanks. Would that be the Large Round Disc on the Driveshaft, and how would one check it's serviceability?