Gearbox/o/d question M46
 

I've asked this over on the 200 series forum but it's just as relevant here. I have just picked up an m46 box with attached j-type o/d. I was wondering whether the overdrive itself can be swapped onto an m41 gearbox as found in certain amazons/1800s etc. If so I'll keep it as a spare. If not, who knows. Thanks,

Dave

Disclaimer:- I'm not really an expert but may be this reply will bump your question higher so someone with more knowledge will notice (!)


I too have a more modern gearbox and overdrive combination that I was planning to fit to my PV544.

I think it is also the one with the J type overdrive.

If I remember correctly the casting is very much different than the earlier PV544 gearbox (which I think is a M40/41 on my car).

I'd have to delve into my storage junk to check this out but I think the J type OD + gearbox combo was fitted to a tilted over engine to allow for a lower bonnet line - this too makes the connections to the earlier upright gearbox more of a challenge.

If nobody can sweep in and give the required gen I'm prepared to make photo's of what I've got showing the comparrisons of the two versions I have...

J type ODs were fitted to M41 gearboxes in the P1800e/s and later 140 cars. I don't know if the M46 had the same bolt pattern though but I would assume they would. I also don't know if swapping from a D type to a J type needs any changes, again I would assume not but don't know for sure.

I would think that the M46 OD isn't compatible with the M41. It would be well documented if it was. The bolt patterns are sure to be different. There may possibly be common parts internally but nothing too relevant I'd think.
The D and J aren't interchangeable on the same gearbox.

I think Derek's point about it being well documented if it was possible probably nails it, and Dai has said on the 200 forum that he's tried it and the splines in the o/d are different. So that seems to be that :)
Thanks all.

100% won’t work completely different setups and gearing also outputs so NO it would not work just buy a decent M41 or do the type 9 conversion 😎👍

Also if you find the rare ! Bell housing you can just bolt your m46 straight in if ! .? You can find the correct bell housing

Kind regards
Robert.w