Transmission Vibrations

[ccooper174]

I have just recently carried out road tests on my Mk 2 3.4 restoration project, (started in 1988.)
Apart from some small items that needed attention, all was fine except that around 40mph some amount of vibration was felt which increased with the road speed. I had changed over the gearbox from D G automatic to
Gatrag 5 speed which is a success apart from the vibration. I had the prop shaft shortened to accommodate the conversion and it was supposed to be balanced at the same time, but I have my doubts. I am looking to carry out tests on the prop shaft in situ with two jubilee clips placed at various intervals around the shaft to see if it makes any difference. Am I going in the right direction?

[piman]

Hello ccooper,

I have heard of this idea but have my doubts that it is practical and feel it is extremely difficult, winning the lottery springs to mind.
Check the flanges for damage, true running and of course ensure the bolts are tight. I would also check the wheels for balance, vibration is a strange effect and can be difficult to pinpoint?

Alec

[PPV]

Hi, can you see any evidence of balance weights fitted to the propshaft? They are usually little square patches spot welded on. If not then unlikely to have been balanced unless machined which is expensive.
I tried on a previous car using jubilee clips. Had some success once I found which position worked. I set one up drove it, noticed any difference then move it 180 degrees and see if change and then 90 degrees etc. However getting under the car each time was a nuisance. I would just try turning propshaft 180 degrees , then if no joy get it professionally rebalanced.
Regards,

[ccooper174]

Hi Alec,
Thanks for your input, I have checked the bolts and the wheels have just had new tyres fitted and wheels balanced. At the moment I am some way through testing with the jubilee clips and hope to win the lottery!
Colin.


Hi PPV,
Thanks for your input also, There is a small square patch welded onto the prop shaft but I think that was put on before it was shortened. I will keep on with the jubilee clips for the moment and if I do not have any joy I will try the 180Deg method.
Thank you everybody Colin.

[ccooper174]

Prop shaft vibrations continued.... I have won the lottery, but after at least 21 adjustment involving three jubilee clips plus final adjustments with the clips weight substituted for a piece of mild steel 1/8" x 1"which weighed 54 grams. Luckily I have a pit that I can drive over and make the adjustments, but I can see that this method without a pit would be laborious. On the up side I was able to use the car over the summer and not rely on a third party to do the job properly. Thank you all for your help and I hope that the exercise will help you with any decisions that you may have to make. Colin.

[Tintin]

Well done - perseverance pays!

I hope you gave appropriate feedback to the people who were supposed to balance the shaft in the first place!!!

Robbie

[PPV]

Glad you fixed it and that you gave feedback on your results.
Regards,

[ccooper174]

Hi everybody again,
I have driven the car though out the summer, but there is still a small vibration at certain speeds.In the winter months I intend to remove the shaft and send it away to be balanced.
Can any one recommend a firm that would do a professional job?
Many thanks for your interest.
Jaguar Chum Colin.