MCI-2 Standard Transmission Needed

[Stormcloud]

Good day, all:

A friend has an MCI-2 with a 6v-71 that needs a standard transmission.
The present factory installed trans is beyond repair. Likely an MCI-5 standard transmission would fit ( maybe?).
It has a driveshaft brake that acts as the emergency brake, and his mechanic says an automatic would not be an option, without major modifications.

Any other options? Anyone have a spare good transmission  in their back pocket?

Thanks.

Mark

[TomC]

His mechanic just doesn't want to do the work.  The MT644 is available with a parking brake on the output side of the transmission.  Would make for a better accelerating bus, but perhaps a bit slower on the hills.  Personally-would find a 6V-92TA (exactly the same dimensions of the 6V-71 with the addition of the turbocharger) and use that.  There were a few 6V-92NA made that were around 280hp.  Just suggestion-the 6V-71, even in a 2 will be slow.  Good Luck, TomC

[Stormcloud]

Hi, Tom:

Thanks for the info.
Is the parking brake air-operated? Where would he look for an MT-644? What were they commonly installed in?
What about cooling? Is it possible to install a separate cooler strictly for the transmission?

Regards.

Mark

[bevans6]

What gearbox is in it now?  I am thinking of clutch and shift linkage.  I have a Spicer 8844 that is probably usable but needs the clutch linkage so if you happen to have that on the old gearbox it might work.

Brian

[TomC]

MT644 is still available through many rebuilders-although it hasn't been made for a while by Allison.  I believe the transmission parking brake was both offered in cable or air operated.  You can add a cooler in front of the radiator or get a cooler with a thermostatically operated 12vdc fan.  Good Luck, TomC

[bobofthenorth]

Sent you an email Mark.

[Busted Knuckle]

What is the difference between a 644 & a 654?
  BK 

[azdieselman]

low gear

[TomC]

Going from memory now-the original MT was the 640.  Rated at 245hp and 600lb/ft torque.  Then out came the MT643 with higher horsepower.  Then the MT644 with larger torque converter-higher torque again.  The MT654 was a 4spd with an additional gear for extra low.  The MT655 was a 5spd close ratio transmission.  The highest power rating I believe was 300hp and 900lb/ft torque.  Maybe someone has some old brochures to verify.  Good Luck, TomC

[Busted Knuckle]

OK I guess my question wasn't clear as mud. Would a 654 work as well as a 644?
  BK 

The reason I ask is a member here on the board has a 654 for sale in the spare parts section.

[Ed Hackenbruch]

According to the sheet i have on my 644,  which also has info on the 654CR,  they both will accommodate engines up to 300 hp. The 644 is good for vehicles up to 50,000 lbs and the 654 is good up to 80,000 lbs. Torque is 780 lbs for both.  The 654 is almost 6 inches longer and 60 lbs heavier. Width and height are the same. Gearing for the 644 is 1st, 3.58  2nd 2.09, 3rd 1.39, 4th 1.00, reverse  5.67.  For the 654 it is, 1st 4.17, 2nd 2.21, 3rd 1.66, 4th 1.27, 5th 1.00 and reverse 10.76

[luvrbus]

FWIW the Eagle used the 654 behind the 8v71 in their buses for years you still see the 654 in Eagles never was a problem 


good luck

[Busted Knuckle]

OK that some what clears up what I was asking.

I just thought if the 644 & 654 were basically the same dimensions that Mark's friend could benefit from the one Eric has for sale.
http://www.busconversions.com/bbs/index.php?topic=21751.0

But I'm gonna guess the 6" will be a deal breaker.
  BK 

[luvrbus]

It shouldn't be a problem BK the 6v71 is not very long

good luck

[bevans6]

The MC5 came with a 740 trans with the 6V71.  Does the MC2 have a similar drivetrain, with a drop box?  maybe a 740 will fit, which would solve the parts problem finding the adaptor and the rest of it.

Brian