One thing you could do... assuming there's clearance from the chassis, you could install a larger flywheel.
where could I find a larger flywheel with a universal coupling?
You might try Northwest Short Line
Their online catalog, part 5 shows flywheels with a bore for the U-joint, just like yours. That's one approach. Lionel and MTH will also sell you a flywheel, or you could have one made at a local machine shop. The trick is having the right size bore to accommodate the U-joint. (Or you would have to change the U-joint on the gearbox end.)
If you're not absolutely wedded to DCS, an ERR Cruise Commander upgrade would allow you to run the loco under Legacy with excellent performance and 100 speed steps. No tach reader required!
JUDD, let me add a bit to Teds response If you have a DCS system you can connect a TMCC command base for not very much about $50 for cable and used TMCC base or a Legacy system to your MTH DCS TIU and control the ERR cruise commander with your DCS controller. The ERR Cruise Commander operates in TMCC but both the TMCC base and the Legacy base in TMCC mode will allow control of your TMCC and Legacy locos with your DCS controller however you will not be able to access the Legacy specific features such as quillable whistle with your DCS controller. j
Thanks for the replies. The reason I would like to use PS3 is to get a proper sound set for a camelback, specifically for a passenger train. I do run both tmcc and dcs engines, and I use the dcs remote to run them.
Some progress made
Up grade completed.