Volvo: 90 240 DL Drive shaft size, shaft size, chassis number

Question
I need to replace the drive shaft in my 1990 240 DL 4D M47 5 Speed manual transmission.  Most parts suppliers have two different size bearings.  How do I find out which one is right for my car.
Thanks

Answer
Russell,
Best way and the most inconvenient is to remove it and measure it. If you have  good eye and look carefully at the cage and bearing, then go to the store that might work. That is what I do, but I have seen so many it gets easy to see. I tried to look it up by year and chassis number but that is still not 100%.