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diggerpro

Needed: Mack TRDL725 Unishift Transmission

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I've been searching for more than a few years  for a TRDL725 Unishift Transmission for my B61  I still haven't given up hope of someone running across one.  I'm willing to pay  a considerable amount for one to keep my B61 all original.  My rear case is split and I also would consider one that has a good case for parts to repair mine.   I have a beautiful truck sitting because of the trans and hate to alter it to drop in the Duplex I have sitting in the shop.  Send me a Pm here and I'll get back to you

Edited by diggerpro

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Is your rear case busted with chunks missing, or just cracked? I've welded a couple back together that were cracked and blasted them to both stress relieve and lessen the appearance of the repair. Why not slip that duplex into the truck till you get the Unishift repaired rather than let the truck set? Same length to the two transmissions IIRC. Do you still have all the hardware that made the Unishift operate? I may have some but not all. My truck had one with a busted rear case also many moons ago. 

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Have a MonoShift in a B65T rolling chassis that was a project that I am never going to get to.

B65 A.JPG

B65 C.JPG

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Im not familiar with the monoshift unless that is a generic term for the Unishift.   Is your trans a TRDL725?    Are you willing to part it out if it is?

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1 hour ago, diggerpro said:

Im not familiar with the monoshift unless that is a generic term for the Unishift.   Is your trans a TRDL725?    Are you willing to part it out if it is?

It's hard to see but that looks like a 67 series trans.    terry:MackLogo:

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UniShift is the correct term for this transmission, I had somehow gotten the incorrect MonoShift ingrained in my mind. Next time i am out where it is parked, I will get a look at the numbers but it should be a TRD725 or TRDL725. For the right $$ i would part it out as no one seems to want the complete project truck with the very nice contour cab

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On 2/5/2019 at 3:16 PM, terry said:

It's hard to see but that looks like a 67 series trans.    terry:MackLogo:

I would agree. The flat top bolt on cover access plate is common to the TR-67 series where the TR-72 series does not have this flat plate. Circled in yellow:

 

TRD-7225 "Unishift":

 

TRD-67 "Duplex" as I don't have a "Unishift" photo:

 

The smaller transmission was common in the single axle tractors in those days.

"Monoshift" was the term when behind a gasoline engine, "Unishift" when behind a diesel from what I've seen and read.

Photos are from my 1965 B series service manual.

Edited by Rob

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I guess that answers what it is, I could find nothing on it to identify what it was other than casting and part numbers. ...QUESTION: Would a TRD67 be what might have been fitted in a B42SX as I have two of them in a returning to nature state.

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A 67 series, most likely, yes. However, it could also be a triplex, or quadraplex too as a duplex wasn't the only option.

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