Great the way things trigger memories.
A good shout to look at engine mountings.
When British Leyland introduced the Princess model, in 1975, there were problems with driveshaft vibration on manual models. The auto was OK.
The fault was eventually found to be the engine position, and the mountings were changed to alter the engine height in relation to the driveshafts.
Weak mountings will allow the engine to drop a little, and the Vectra/Croma may be quite susceptible to this.
Have a very good look at the engine mountings. Do they look even slightly sagged?
When you looked at the pics were there any grease apparent?From the thread mentioned above:
>My 2001 Vectra B has 61k - bought it recently. Steering wheel was
>off centre and vibrations from around 60mph
>...
>I now have a vibrating steering wheel at 78-82mph.
My car vibrates at 15-20 mph, I highly doubt that wheel unbalance would manifest itself in such a low speed. The vibration also occurs with both summer and winter tires that are on their own rims.
It seems that driveshafts can't be blamed after all. The garage dismantled the 25000 km old shaft and showed me pics of the tulip, no apparent signs of wear.
A auto box specialist test drove my car his opinion was the box can't be broken because there are no extra noises.
I'm beginning to suspect the engine mountings. Now I'd like to know, are any of the Croma's mountings liquid filled?
<SNIP>
Only grease I can find for inner joints is this: https://www.merlinmotorsport.co.uk/p/gkn-tripode-joint-grease-300-grams-gkn-ms9u025
Expensive for just two joints, but significant that GKN market two different greases for inner and outer joints. Their products!
Did any of you 3 with this problem ever find the reason ? Its cost me a lot of money to have 2 new complete inner & outer drive shafts fitted (they arrived from Italy as full units for each side, so inner and outer were already connected). Even now the car is still shaking badly when accelerating at 35-45 mph, especially uphill. I am really sick of the problem now, I even had the engine mounting under the battery removed, inspected & re-fitted, that's not the problem. I suspect the gearbox is the problem, but the autobox specialists say it cant be as otherwise the gearbox would be leaking oil as it would have blown the seals. Any help very appreciated. Remember car hit a huge pothole prior to the car starting to shake (but did not shake immediately, only after 1000 miles or so)