Noise at 20 mph

[not hereplease]

1988 740 Volvo Estate.

At around 20 mph I get a strange rumble noise.
I have tried the car downhill with the engine off, ( no other traffic
around ) and the noise is there so the noise must be in the transmission or
wheels.
The noise does not appear to be coming from either of the rear wheels.

I note that the Speedo works off the back axle, could it be this making a
noise if not ay suggestions on what the noise may be.

 

[Peter Milnes]

It could not be the back axle noise being transmitted to the speedo as the
connection is purely electrical. Possible culprits are - exhaust system touching
chassis or underside (could be due to engine mounting or gearbox mounting
failing), centre bearing on propshaft failing, wheel bearings, gearbox tailshaft
bearing, and there are a few more!! Start by eliminating the ones I have listed.
If you do not find it then come back and we will look up the others.

Cheers, Peter.

: 1988 740 Volvo Estate.
:
: At around 20 mph I get a strange rumble noise.
: I have tried the car downhill with the engine off, ( no other traffic
: around ) and the noise is there so the noise must be in the transmission or
: wheels.
: The noise does not appear to be coming from either of the rear wheels.
:
: I note that the Speedo works off the back axle, could it be this making a
: noise if not ay suggestions on what the noise may be.
:
:

 

[Gary Heston]

1988 740 Volvo Estate.

At around 20 mph I get a strange rumble noise.
I have tried the car downhill with the engine off, ( no other traffic
around ) and the noise is there so the noise must be in the transmission or
wheels.
The noise does not appear to be coming from either of the rear wheels.

[ ... ]

In addition to the other suggestions, check your universal joints.


Gary