Does anyone have information about the possibility of swapping a 4 speed MT 647 Allison for a 5 or 6 speed Allison? On my coach it would have to be very close to the same physical size as there is not any room for a longer transmission. Hoping to find a way to add an overdrive.
Thanks in advance.

If I remember correctly you have an 8.3C engine. Easy swap. You can use an 3000 or 4000. Also the 2000 would work, but would require a longer driveshaft. The reason for the 2000 instead of the 1000 is most 2000 have an SAE 3 bellhousing.

I think you have a cable shifter which should work for the 2000.

As you know I replace a 545 with a 2000. Great decision.

quote:

Originally posted by Gary Carter:
If I remember correctly you have an 8.3C engine. Easy swap.

I think you have a cable shifter which should work for the 2000.

As you know I replace a 545 with a 2000. Great decision.

Tom's coach is a CAT 3208, with a Stone Bennett Air Shifter.

Nick

Same story, might even be able to use the stone Bennet.

Or the other option is change the RE gears. Our Newell with the 740 had 3.33 gears. 3.73 gears would give you 67mph @ 2100rpm.

I believe I have the higher gears as 67mph is about 2100 or so. I am looking at the MH 4000 which is an electronic 6 speed so I probably have to add the computer and another shifter. But if I can get a 6th gear with a .80 or taller OD the specs say I should cruise at about 1700 RPM and that would,give me about 15% improvement in mileage. My engine is the same as Nick's - a Cat 3208T. It is a 10.5 liter (636 ci) displacement and has been great no matter what hills I find. Just looking to improve from about 9 mpg.