Shuddering under accelleration

Having problem with 2001 TD4, symption was shuddering setting off and turning at say traffic lights. Had wondered about the VCU, after debate over its resistance just took the props and it off. That's made things worse, also shows under acceleration in a straight line. Checked round the front end, no play in wheel bearings, trackrod ends and other joints, bushes seem fine, its had relatively recent driveshafts and lower suspension arms.
Any thoughts or suggestions?

BrianHe said:

its had relatively recent driveshafts

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I bet the drive shafts aren't Genuine GKN shafts. Anything other than GKN shafts cause vibration under acceleration.

The aren't GKN as a pair would be more than the cars worth. They have been on a little while and been fine, and have no detectable play. It's not an even vibration, more like the pulsing some and systems produce.

BrianHe said:

The aren't GKN as a pair would be more than the cars worth. They have been on a little while and been fine, and have no detectable play. It's not an even vibration, more like the pulsing some and systems produce.

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Definitely sounds like driveshafts to me. The inboard joint is the issue with them, as they bind under load. The fact that making it FWD has worsened the vibration, pretty much proves it the driveshafts. Also it's worth replacing the lower engine tie bar, as the large bush goes soft, exaggerating the vibration.

You can get reconditioned GKN shafts, which aren't super expensive, and don't seem to vibrate.

Will have a look at the tie bar when the weather permits. Will have a think about the driveshafts, as was thinking the car was beginning to reach end of life.

BrianHe said:

Will have a look at the tie bar when the weather permits.

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It's easy enough to check .

BrianHe said:

Will have a think about the driveshafts, as was thinking the car was beginning to reach end of life

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That's depending on anything else that needs attention. If it's otherwise in good condition, with bodywork good for a few more MOTs, then it'll be difficult to replace it for something better. The FL1 is still holding its money, so it might be worth more than you think.