Triumph Repair: dpitfire rear end shakes when letting out clutch, worst case scenario, rubber bushings

Question
I have 1969 spit in great condition recently rescued from storage .  the car runs great but when letting out the clutch the rear end seems to be shaking and making noise.  any hints.  

Answer
Jeff,

Is it just a momentary shake or does the rear end keep shaking while the car is driving?

The Spitfire differential is held in place by a long bolt through the frame and two ears on the diff casing on the back end, and bolted up to the frame by two nuts onto studs welded onto the frame at the front end.  If the front mounts are loose or the rubber bushings are shot then you'll get a shake.

Another cause could be any of the 4 u-joints (or their flanges) in the drivetrain.  Put the car up on proper jack stands and carefully check each u-joint for free play and check the flanges to make sure they're tight.

It's also not a bad idea to make sure the lug nuts are properly torqued (38 ft-lbs max... or you can snap a wheel stud!) as it could be a loose wheel.  Also check the center bolt that holds the rear hubs to the axle.

Moving on it could also be the bushings in the vertical link or radius arms.

The worst case scenario is that the differential itself is bad.  It could be either bearings or the ring gear/pinion may have teeth missing.

Cheers,

Jim