Gearbox - 144

[142 Guy]

If what you want is closer ratios the M47 (or M46) is definitely not the answer. If you check the actual ratios (1-4 appear to be identical on the M46 and M47) the 1-2 and 2-3 shifts are all farther apart on the M46/M47 than they are on the M40. The M46 and M47 come with a very short first gear 4.03:1 (the M40 is 3.13) so those cars must have had a very tall rear end.

The Getrag M51 used on the Volvo 264 was a 5 speed with a 1.00:1 ratio on 5th; but, has a first gear similar to the M46 which would be suitable for pulling a plow in the field with your 4.56 rear end. If you change your rear end the M51 ratios from the 260 might work better; but, when you look at the 1-2 and 2-3 spreads they are not closer than an M40. The M51 might be pretty rare because every 260 series that I have ever seen on this side of the Atlantic had a slush box. The M51 would definitely not be a drop in fit. The Volvo GPA 240 cars used an M51 with very tight ratios; but, with a very tall 1st gear - which might work with your 4.56 final drive. Good luck trying to find one of those!

I don't know what T9 variant your Seven has; but, the ratio spreads in the T9s that were in the XR4ti / Sierra appear to be more like the M46/47. It is an OD 5th, 1:1 4th so not an inherent close ratio box. There are different 4 cyl versions; but, they all appear to have a wider spread between 1st and 2nd than the M40. Some have a 2-3 spread that is close to the M40.

Reality is that compared to most other transmissions, unless you are prepared to try customized gearsets you are going to have a tough time finding another transmission with closer 1-2 and 2-3 ratio spreads than the M40. Here are some resources with transmission ratios that will demonstrate how hard it is going to be to find a closer ratio gear set than the M40.

https://people.physics.anu.edu.au/~a...s_compared.htm

http://www.nuceng.ca/bill/volvo/database/tranny.htm