Propshaft assembly orientation

[frank rabbets]

I stripped and rebuilt a DB4GT in the 80's. I had not driven it before as it arrived in bits. So setting off on my first test drive after 20 mph there was a terrible grinding noise like a sort of hammer drill. If I went up to 50mph the noise and feeling was unbearable. It seamed to be throughout the car. I changed the propshaft and gearbox which a friend gave me but no better. So I was lying under the car in tears. I suddenly realised that the gearbox flange was slightly pointing towards the floor but the axle flange was also pointing towards the floor. WTF this car has 4x identical trailing arms locating the rear axle as confirmed by part numbers...........well hopefully it HASN'T. So with a heartrate of about 200 I took them off and there were 2 short and 2 long. By some fluke I'd put them on in exactly the wrong combination. After another 30 mins I had them back on and was in tears of relief as it drove like silk. On obtaining the Aston Martin service records that car had been immediately returned to the factory by the first owner for nbearable noise. The comments were " manufacture and fit purpose made trailing arms for rear axle". The chassis must have been jigged wrongly.

The noise was the play in the gearbox and rear axle being taken back and forth twice every revolution of the propshaft.

 

[Crispin]

I was under the 150 this morning and checked both front and rear and neither is phase. They look like they're a few splines out but deaf not lined up. Might it be of no importance in this application?

Sent from my GT-P7510 using Tapatalk 2

 

[frank rabbets]

Only the Factory Workshop Manual will tell you unless you have the original marks, sometimes a paint line across the joint. Some cars have joints which are a few splines away from either in or out of phase. Sometimes there is a master spline so you cannot slide the two halves together incorrectly.

Frank