Two years ago the B16 engine in my 59PV started tipping forward so that the fan would graze against the radiator. This happens only when the back end is under alot of torque, as I release the clutch to start on a hill and such times. A friend (in a pit under the car) saw that the differential will twist so that the bottom pushes forward, pushing the driveshaft, tranny and engine forward. The engine mounts are good, and the axel braced. I took out the rear section of the driveshaft, and it shortens and lengthens smoothly about 2 inches. Have any of you seen anything like this? and do you have suggestions about my problem? Thanks