I'm hoping I can get feedback and help from the forum. My 1967 95 V4 has started making a loud clicking / tapping noise when engine braking. When the car is accelerating everything works as normal, gear changes are smooth and without much noise. Once I let off the gas pedal or when engine braking the tapping noise becomes noticeable (and loud depending on engine rpm's). I'm guessing the problem is in the gearbox but I'm not 100% sure. The engine sounds normal. When the freewheel is engaged the noise is still there but not very audible.
Use the freewheel! No engine braking. Problem solved! Seriously though, Googling suggests worn diff/bearings or chipped gear. Could be driveshaft or CV joint though.
Rear gearbox mount? Maybe the rubber has broken down to nothing and the gearbox spigot is rattling metal to metal. If so you can view the movement after removing the plate inside the car but I believe you can also see the rear of gearbox rising and falling as you blip the throttle, when viewed from under the hood.
I hadn't thought of the rear gearbox mount, I'll check that out today. My gut feeling tells me it's something worse, possible the differential bearing as suggested. The freewheel seems to be working as normal so I don't think it's stuck. Thanks for the help!
Topic 
Gearbox noise -tapping when engine braking
Posted - 05 Jan 2015 : 00:11:15 
