I aquired a M41 recently that may have come from a '67 1800S. It appears to be a type "D" Overdrive. Gearbox part # 254409, and the Speedometer gear is part # 380305. My question is what rear end ratio was used with the # 308305? I believe the only ratios available were 4.10:1 and 4.56:1. This trans is destined for my '70 145 w/ 4.30:1.
Thanks for any help.

The 1800 your transmission came out of woulda had 4.10 gears. Your 140 wagon should have 4.30. Difference ain't too much... I wouldn't worry about it greatly. It'll just read fast. There is a chance that the speedo gear out of your old transmission might fit... can't say about that. When I did that to my '70 wagon, I changed both the transmission and rear at the same time... both from the same 142. So I didn't ahve to worry about it. If you can't find the gear, you can always swap rear ends with one from a sedan... that will also give you slightly more relaxed highway cruizing...


I'm in about the same boat though with a different car.... I've got a '67 122 wagon with 4.56 gears, and a M41 out of an unknown (presumably came in a car with 4.10 gears). Speedo reads fast... Is there a speedo gear that fits in a J-type OD that will be appropriate for the short gears of the 122 wagon?

-Matt

Matt,
I appreciate the input. I find speedometer errors annoying. Near as I can tell, if indeed the M41 did come from a 4.10:1 car, I'll be in business. I also think in that case the speedometer error will be almost nothing.

My calculations indicate about a half mph difference at 67 mph between a 4.10:1 with standard 165x15 tires (the 1800) and a 4.30:1 with the taller 195-75x15 tires (my 145.) I was surprised how close in diameter the 195-75x15 is to the original equipment 6.85x15 tire.

I'm getting way to detailed, I don't think the old speedometers were always on the money anyway. Still it is an interesting thought.
In any case, I do have a 4.10:1 axle out back somewhere....

Regarding your 122, my books show an overdrive used with a 4.56:1 in 60's 1800s from the factory, so there must be a correct gear out there somewhere. Although I guess that would not be on a "J" type.

Thom

A '67 1800 would have come with 4.56 gears, not 4.10. Volvo used to offer alternate drive gears, but I don't know if they're still available. ???