This is a continuation of the thread I started "Is this a genuine M119 engine".
We've now completed the swop of the 4.2L found in my E500, to the 5.0 litre I've taken from an SL (what a transformation in performance!).
However, we've been left with what I can only assume is a driveshaft vibration. This can be initially (and only slightly) felt between 48 and 53 mph, and then it disappears until the 95 to 105 mph range, beyond which it again disappears.
(We have discounted wheel/tyre imbalance, having tried various sets of wheels/tyres - all meticulously balanced - with no improvement. Also, before we carried out the swop, there was no hint of vibration, so I assume we can safely assume that the fault does not lie with the flanges (all of which look good), or the centre flexible coupling).
To recap, the engine/gearbox/driveshaft front flange is from the SL. This front flange connects to the original front half of the driveshaft from the E500. We did have to remove the whole driveshaft when fitting the engine/gearbox, but have ensured that the markings front and rear of the centre bearing line up as per the manual.
However, as far as the front flange connection to the gearbox is concerned, in the MB manual I can only find reference to alignment arrows when it is (for want of a better description) a three-pronged connection.
My E500 (and the flange from the SL) has a four-pronged connection, and there are no arrows or other obvious markings on them which might suggest there is a correct way to line them up. However, could this area be the possible cause of the vibration? Despite having no obvious markings, is there a correct/incorrect way of lining up?
Any help, anyone?