report of my 240 M90 swap:
Clutch works great, it is the dog-dish flywheel with a 940 M90 diesel kit, 260 master cylinder+pedal, 940 slave cylinder and the 940 hydraulic line with a few new bends. I might try a small teflon spacer between the slave cylinder and the clutch fork to see if it behaves any different, but it is already very good. Not much pedal effort needed.
The gearbox I have comes from a crashed 1995 model 940, it is a M90H (slightly longer 1st and 2nd gear compared to the M90L). I replaced all the gaskets and replaced the oil. No 3rd gear synchro welding, I tried to remove the shaft but it was too much work to remove it and I didn't wanted to lose any parts.
No bodywork mods needed (as expected). The gearbox is a bit close to one part of the tunnel but that is just one of the casted tabs to space out the tunnel insulation on the 9xx models that got that stuff. If it gets too close i'll grind it off.
The gearbox crossmember required some work. I used the M47 support of my 240. Just position the 240 under the car with a jack, fit gearbox mount and hold the crossmember under a set of bolt holes (the bracket is positioned 2 holes further to the front now) and eyeball where the cutout for the mount has to come. Mark it, measure twice, cut square hole. These pics show it better than i can explain.
Here is the crossmember with ready for the mount.
With mount. I used inbus/in-hex screws to attach the mount to the x-member.
How it looks, mounted. You can see 2 small holes on the underside of the x-member to access the in-hex screws.
The shift linkage. I shortened the aluminium piece ~100 mm, the steel shift rod 100 mm too.
For the little shifter support on the left I cut up the little bracket and welded it to a plate that was narrow enough to fit over the 2 mounting holes in the tunnel. The 240 has 4 M6 threaded holes around the shifter. The rear 2 are used for this bracket now.
Because the tunnel of the 240 is pretty narrow you need to install the pin on the right before the transmission is in place. With the engine in the mounts, cylinder head resting against firewall, you can barely squeeze the pin in place.
On top of the tunnel, I used the rubber bellows that came with the 940. The upper and lower bellow fit great in the 240 carpet. The steel plate you see is also from the 940. The 2 little studs on the left are the protruding screws to mount the shifter support. 2 holes drilled in the steel frame to hold it in place and a bit of hammering to massage the steel plate over the 240 tunnel. Use some zipties to hold the leather shifter cover down.
Watch out with the hammer so close to the head unit, a hammer is attracted to expensive stuff.
No bodywork mods here, not even an extra hole drilled.
Driveshaft: I used the rear piece of my 240 since that is very thick. The front piece came from a 700/900 series with M47. I had the front piece shortened 30-35 mm and balanced together with the rear 240 section. A 700/900 series support bearing was used too. I'll double check the length of the driveshaft for people who want to do this swap in the future.
How it looks in the car:
The shifter fits in perfectly.
I only drove the 240 for 4 km since this swap, still have to finish some stuff like the exhaust, some interior stuff etc. The short test drive showed that everything is working great, no noises, no odd vibrations, all gears work. A very nice upgrade.
) Under load...400lbft seems to be a recurring number...obviously weight, tyre, and driving style dependent.
