Prop shaft Centre bearing
 

Does anyone know which size bearing is used on the later 940s?

M90 B230FT 1997

Best bet is crawl underneath and measure it with a Vernier gauge. When you buy a replacement, don't buy the bits separately, buy the fully assembled one with the bearing already fitted to the carrier. When you fit it, take it for a test drive and if it vibrates, note what speed it vibrates at. Return home, crawl underneath and loosen the 4 bolts securing the carrier to the floorpan by no more than half a turn.
Take it for a short test run up to the speed (accelerate gently!) where it vibrated and then return hoe and tighten each bolt a little at a time (1/4 turn max) then next bolt and once you've done all 4, do them again, 1/4 turn max at a time until they're all tight.
Test drive once they're tight to confirm the vibration has gone. If not, repeat the loosening, test drive, tighten etc but it's usually sorted on the first time. :thumbs_up:

That’s what I was hoping to avoid, but if no one knows I’ll have to get under and measure it.

Chances are it's the 45mm one but the only way to be sure it's not the 75mm one is to measure it. Both were fitted and it's possible (not probable, just possible) it may have had a replacement propshaft at some point so the only way to be sure is measure it.

Have you got a friendly local garage who would let you put it on their 4-poster ramp to measure it? Would save getting cold and maybe damp! :thumbs_up:

https://www.ebay.co.uk/itm/VOLVO-740...Y/171414215412

45mm complete bearing/carrier ^^^^^

https://www.ebay.co.uk/itm/For-Vauxh...m/252154914255

75mm complete/bearing/carrier ^^^^^

If it was in front of you in normal conditions, it would be easy to just look and see the difference, when it's under a car, things look different so measuring is a must. :thumbs_up:

m90
 

if it's an m90 gearbox then its the big bearing as the prop is thicker than an m46/7 one.