sudden bang

whiterover

whiterover

Member
Hi Everyone. The other day whilst pulling away from uphill traffic lights there was a bang and a rattling noise we didn't go anywhere. So after a ride home with the A A, I went underneath and found that I could turn the driveshaft without the wheels turning, clanking noise coming from inside the extension case. is this something that happens to p6's. So I guess that is where the problem is. Fortunately I have a spare diff from a 74 series 2 car, my question is are the cases interchangeable, if the they are a really easy fix, hope hope.
John.
 
Very common, especially on the early v8s. Sudden change in direction, engagement of gear, or traction after loss of traction are usually the culprits.
You can change the whole diff or just swap a good driveshaft from your donor into yours, doing it all in situ.
The important bit is how the splines sheared and getting all the debris out before refitting with the new part.
I have seen a very clean break once or twice, just make sure the jigsaw of pieces are all complete on the bench after removal, otherwise you'll need to be sly with magnets etc, or disassemble more of the unit to clean it out thoroughly.
Jim
 
That happened to my Series 1 V8 a while ago :(

I fitted a refurbished Diff with new seals etc, so I hope I can leave it now for a few years at least...
 
I have a spare diff that was given to me several weeks ago, just the diff no drive shafts.
Should I dismantle it and check it out so that I am ready for the future?
Or is it that the drive shafts shear and not the banjo inside ?
Peter
 
ButterFingers said:
I have a spare diff that was given to me several weeks ago, just the diff no drive shafts
Click to expand...

I am assuming you mean Peter, no half shafts. The half shafts are external, and link the differential to the hub, containing two universal joints per side. The drive shafts are internal and can be identified by the circular flange on either side of the differential, onto which the disk in positioned, and the half shafts will bolt.

The drive shafts are the weak link in the differential, but it is the style of driving that breaks them. The moment a spinning wheel regains traction, enormous amounts of torque are experienced by the drive shaft involved, and this the major cause of their failure. You can remove each of the drive shafts to check for twisting of the splines if you so wish.

Ron.
 
Hi. Thanks for replies. Well the replacement casing and shaft bolted straight on and we are mobile again. It was a nice clean break. I wonder why they break on both the 4 cyl and the 8cyl when the engine output is so different, perhaps a bearing on each end of the shaft would have prevented this happening?
John.
 
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