Quote:
Originally Posted by Rversteeg
Don't worry about a slight rumble when setting off with a fully loaded car. It is most probably due to the prop shaft not being fully aligned when torque is applied to it. Under ideal circumstances the uneven movement of a universal joint at an angle is cancelled out by the second UJ in the prop shaft. In reaction to your car setting off, the rear axle will rotate in its rubber suspension, causing the nose of the differential to rise. This will put one UJ under a greater angle than the other one, resulting in an uneven movement of the prop shaft. This is the slight rumble that you are feeling.
The UJ angle also increases when the rear axle is loaded. This added to the rising differential effect makes the rumble worse when loaded and not noticable when not loaded.
You can a) reduce the diff rising effect by replacing the torque rod rubbers, b) reduce the basic UJ angle by putting shims underneath the prop shaft bearing or by increasing the riding height of the rear axle, or c) just live with it if you run it mostly empty or light loaded.
Reading about your holidays it seems like every trip is an adventure. On the continent our holiday trips are usually much longer without any problems. I usually travel with tools and several spares just for ease of mind, as they always remain untouched. I'm always comforting myself with the thought that she has been running 15k miles every year for the last 20 years without major problems, so why would she just break down on this particular 2000 miles holiday trip?
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Hi Rversteeg,
Many thanks for your thoughts on my possible transmission noise, and your explanation certainly makes sense. Tried her out today and could not replicate noise, so you have probably identified the cause.
I do have the transmission joints/bearings on my 'to do' check list as there is quite a bit of driveline shunt when going from P to R or R to D, I shall check out the UJ's at the same time.
Cheers
Steve