I bought my second 1800 a bit over a year ago, a '70 1800E and started working through various issues it has including transmission bearing noise. I've recently discovered that I have one of the relatively (very?) rare M410 transmissions that were installed in SOME 1800'S. I think it's orignal and not a transplant because the input shaft matches the one in the M41 (same clutch plate). Since I discovered this, I've been looking back through the service manuals I have and it looks like NONE of the 1800 service manuals mention it as an option. I haven't reviewed every P1800 service bulletin I can find yet, but I've yet to find any mention of the M410 in those I have looked at. Poking around the net a bit I've seen a few opinions about the use of the M410 in the 1800, but what I'm trying to find (out of curiosity as much as anything) is a more exact history of how many may have been installed and, above all WHY did Volvo create such an apparently rare beast? From what I think I know, the M41 worked very well so .... WHY?

For what it's worth, Kudos to Christer at VP-Autoparts ( http://www.vp-autoparts.com ) for saying he'd be happy to take back the M41 gasket set I had ordered since I couldn't use it.