Question on D2 5U 17000 series tractor

The tach drives are common to the industrial and gen set units including the D311 engines same as D2. The drive cable drives the tach through a 90 degree drive mounted to the back of the unit. I suspect your DW20 tach is set up for opposite direction rotation. Gear changes and rotation change devices are/were made by Stewart-Warner Co. You might be able to still get what you need.....or get the tach designated for the D311, part #4H2882 with the #1L9122 right angle drive adaptor.

I installed a tachometer on my D2 by mounting it in the factory hole in the dash normally used for the pony electric starter nose (this dash was used on early U series). I use rope start for the pony, so space was available for tach. OM is correct, cable reverse drive parts are available from Stewart Warner and similar suppliers. I put my reverse drive above the front gear housing. The reverse drive was configured as a 90 deg gear set which was very convenient as I needed a 90 deg bend in the cable to go over the top of the engine. Also when you go from clockwise to counter-clockwise cable drive you need to use "left" and "right" wound inner cable wire to prevent the cable from unraveling.

Thanks KCB,
Forgot about the cable thing😊

I think the real reason you don't see mechanical tachs mounted on many tractors is that the drive mounts in an extremely vulnerable location and soon would get knocked off.....plus there really is no need. Looks good on a trailer queen though.