Allison Trans Mt647

Discussion in 'General RVing' started by murphy5856, Nov 15, 2008.

  1. murphy5856

    murphy5856 New Member

    I have a 1990 Beaver with a Cat 3208 and Allison 4 speed trans. I would like to change to a 6 speed does any one know what model I need and what's involved in the changeover? Thanks Ken
  2. dbarton291

    dbarton291 Senior Member

    RE: Allison Trans Mt647

    That would be a very complicated and expensive change. The MT647 is hydromechanically controlled. The six speed is electronically controlled. You would have to buy the controller, get the right program in it, the shift selector, throttle sensor, wiring harness, the transmission itself, shorten the propshaft, and then figure out how to wire the whole thing up.....and I don't mean just power and ground. Oh, and you'd have to get someone in the Allison network to run an iSCAAN on it to figure out which torque converter you need with the transmission AND the correct axle ratio to use.

    You sure you want to try this?

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