Diff torque rod

[Uboat]

Hi,

What is the function of the torque rods attached to the ears of the differential?

I noticed that mine are loose and the bush only touches the ear of the diff with a millimeter of play. Is this how they should be?

/Ulf

[paddy]

Without the torque rods the diff just hangs from the two top mounts, and is free to swing forwards and back in response to torque loads arising from the driveshafts (ie torque on a transverse axis left-to-right, rather than an axis front-to-back in line with the propshaft).

The torque rods govern this movement and essentially fix the position of the diff except that they permit very limited forward-to-back movement to cushion the driveline a little. If the fittings are loose, the diff will move too much, with the nose usually hitting the chassis either at the top or the bottom on drive or overrun. Apart from hitting the chassis, the excessive movement I guess would also cause premature failure of the top mounts.

When the torque rod bushes are fully tightened (so the outer cups are tight up against the spacer), the amount of movement is really very limited. I don't know if anyone here knows how much is expected. On mine with brand new bushes from TTR the diff is hard to move perceptibly by hand, and can be made to move by only a few mm with a crowbar between the diff nose and chassis. (I this too tight?)

Paddy

[elansprint71]

I think that rather than to cushion the drive-line (as you say movement is minimal), the function of the rubber mounts is to cut down NVH by isolating the diff from the chassis. You could bolt it directly to the chassis but the noise would be a bugger.