Bent torque arm?!

[DragoMack]

Yesterday my driver came to my yard with the torque arm bent. Any idea what would cause this? She said she had a normal day. The u joints of the shaft between the tandem were shot. 
this is a 97 triaxle ch613

[Vladislav]

Bolts were overtorqued when the rod was installed and broke down at a certain time. Or opposit situation they were loose and got gone. After either of the scenario the axle got ability to spin over its mounting bushings by acceleration or brake torque. The rod hit the crossmember and got the shape you see. U-joints kept its company by the same reason.

Of possible traces to proof my suggestion I would look over the crossmember surface for punch marks or scratches made by the rod since it too probably made multiple hits. Also I expect one of the bolt holes worn to one side since two bolts were doubtly ruined together. One of them hold on for a bit of time before to get bend broken.

Vlad

[kt_Engineer]

19 hours ago, DragoMack said:

Yesterday my driver came to my yard with the torque arm bent. Any idea what would cause this? She said she had a normal day. The u joints of the shaft between the tandem were shot. 
this is a 97 triaxle ch613

 Your driver is not telling you the truth. It takes incredibly amount of force to bend the torque rod like that. Considering none of the other components are damaged, my best guess is one end of the torque rod was coming loose and truck hit a huge pot hole causing the axle to articulate pushing the torque rod against the cross-arch and bending it (look for marks on cross arch where it would have been hit by the torque rod).

Either that or Hulk tried to pull the rod out to hit someone when your driver was not around the truck.

[Mark T]

(lol)   if that's a "normal day" ??  WOW      looks like it needs to be bushed, let alone that bracket for the side torque arm doesn't belong on there on that front rear

[Rob]

9 minutes ago, Mark T said:

(lol)   if that's a "normal day" ??  WOW      looks like it needs to be bushed, let alone that bracket for the side torque arm doesn't belong on there on that front rear

Yup. Probably a replacement front drive and the bolts didn't get properly addressed, worked loose through use, and departed the mount. Looks like an aggressive driving style was the final nail in the coffin for the parts. Truck probably needs greater attention than just the torque arm.

[Joey Mack]

Christ almighty!!!!!     I'm guessing the box rubbers have been blown out for a long time. 

Edited May 7, 2021 by Joey Mack
More content needed

[kt_Engineer]

Also, I noticed something that doesn't make sense. The fore-aft torque rod is in the wrong direction. It should be mounted facing towards the front/cab and not towards the rear. Also the front-axle has the straddle type bracket but without transverse torque rod (mounts of the side frame rail). The rea-axle has tapered torque rod bracket and transverse torque rod (as it should). This does not look right (also strange front-rear has different bracket type than rea-rear).

[DragoMack]

9 hours ago, kt_Engineer said:

Also, I noticed something that doesn't make sense. The fore-aft torque rod is in the wrong direction. It should be mounted facing towards the front/cab and not towards the rear. Also the front-axle has the straddle type bracket but without transverse torque rod (mounts of the side frame rail). The rea-axle has tapered torque rod bracket and transverse torque rod (as it should). This does not look right (also strange front-rear has different bracket type than rea-rear).

I bought this truck used over a year ago so I guess I’m dealing with all the negligence of the previous owner. He did tell me the front axle is a replacement. Truck does do tough work running through loose dirt pits. Although I will also note that the front tan dif was repaired recently so my guess is that during the install my mechanic didn’t properly tighten the bolts of the torque arm. Could you further clarify about the fire aft facing the wrong direction? Is that the rod mounted to the frame in the rear? Is the “pin” like part supposed to be facing the cab and the torque rod on the back side of the bracket?

[DragoMack]

9 hours ago, kt_Engineer said:

Also, I noticed something that doesn't make sense. The fore-aft torque rod is in the wrong direction. It should be mounted facing towards the front/cab and not towards the rear. Also the front-axle has the straddle type bracket but without transverse torque rod (mounts of the side frame rail). The rea-axle has tapered torque rod bracket and transverse torque rod (as it should). This does not look right (also strange front-rear has different bracket type than rea-rear).

Also, do I have the right set up for these rods? I’m new to Mack trucks and the truck came set up as you see. The torque rods were put on the inside side of the axles where the hole mounts are. The rod length of the front is about 21 while the back is about 24. Is that the right length? I plan on getting new rods next Monday so I want to get the right stuff

[Joey Mack]

Mabey need to replace the box rubbers on the spring ends, install the "Twinkies" as well, then take the front transverse torque arm bracket and move it to the rear, and ditch the ball joint type bracket. You can set the axles on stands (in the chassis) and rotate them to straight up, (if they need to be rotated) then measure the distance from the A-Frame mount holes to the front of the torque arm bracket, as stated before,  and that should be the "on-center" measurement to order torque arms by length, if using the VIN doesn't work..... they are shimmed with 5/8" washers.  

[fjh]

10 hours ago, kt_Engineer said:

Also, I noticed something that doesn't make sense. The fore-aft torque rod is in the wrong direction. It should be mounted facing towards the front/cab and not towards the rear. Also the front-axle has the straddle type bracket but without transverse torque rod (mounts of the side frame rail). The rea-axle has tapered torque rod bracket and transverse torque rod (as it should). This does not look right (also strange front-rear has different bracket type than rea-rear).

Holy crap ! I believe that is as rear torque rod that has been put in the front location ! I have had this happen twice where the parts guy looks a the drawing of the parts break down and interprets it back ward ! The impact program is a poor setup ! Very hard to navigate in some places ! this is one of those places!  This doesn't explain the bend how ever Looks like the front of the diff was driven up on a huge rock or something! 

[kt_Engineer]

6 hours ago, DragoMack said:

I bought this truck used over a year ago so I guess I’m dealing with all the negligence of the previous owner. He did tell me the front axle is a replacement. Truck does do tough work running through loose dirt pits. Although I will also note that the front tan dif was repaired recently so my guess is that during the install my mechanic didn’t properly tighten the bolts of the torque arm. Could you further clarify about the fire aft facing the wrong direction? Is that the rod mounted to the frame in the rear? Is the “pin” like part supposed to be facing the cab and the torque rod on the back side of the bracket?

There are different setups based on suspension. I was thinking it has to either look like the Image 1 (in this case it shows a rear-rear carrier) or Image 2 (which is a front drive axle) where fore-aft rod it going towards the cross-arch but will not have the straddle bracket in thee back. It would have a TELMA bracket mounted towards the front of the the carrier with a transverse torque rod mounted of the cross frame-rail. Your current setup has nothing to prevent front drive axle from moving side-to-side. This would be acceptable for some suspension configurations (but not all) if I remember correctly.

 

 

[Mark T]

That bracket on the rear of the front carrier does not belong in that application.  Period .  Someone likely stuck that carrier in there and didn't feel like taking it off (likely to avoid removing the output yoke)  safe bet the rest of it was a little neglected as well.....so it needs to be bushed  . That bent rod contacted the bracket (that doesn't belong there) and bent until it broke the bolts.  That's about a ten or twelve thousand dollar repair. OR  just put a new rod in where the bent one is, replace the side one in the back and cut the bracket with a torch to give the rod room (lol) probably everything is worn out in the back of it.

[fjh]

In the original pic It appears to be  Camel back suspension the chair looks to be a aftermarket replacement  the torque rod set up looks correct except for the front in my mind  the front bracket rod is not there that's fine for a camel back as mentioned the bracket doesn't  belong there! get rid of it! or put it on the rear its a better set up than the rear one! maybe it hung up on the torque rod and  bent it  Either way just splitting hairs I can't fathom bending that torque rod have no explanation ! other than some superman event! 😂

Edited May 9, 2021 by fjh

[Torque arm]

Hello. Hope to find some suggestions. We have a fleet of 567’s one truck in particular has an issue with the transverse torque arm breaking off at the welds on the differential. This is the third time in a year. We do do a lot of off road on rough terrain. I’ve watched this truck operated and do not think speed is the issue could this be caused by anything else?

[Joey Mack]

can you post a close up of the damage?  Welcome aboard...  Jojo