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bowler1's avatar
bowler1
Explorer
Aug 18, 2014

Transmission Questions...???

Hi,

This is somewhat of a followup to my post about towing in the mountains with a gasser.

In that post I saw a lot of talk about different transmission designs, how they have changed over recent years, and talk about transmissions "locking out" in every gear.

Can anyone expound upon what this all means and how transmissions and designs differ for towing applications? What makes one transmission better than another?

For instance I have always heard people comment on the superiority of Allison transmissions. What would make them better than another design?

I would think that the main difference in transmissions would be in quality and longevity (which I would think is a function of quality of the parts and the build), but I am not sure how this would be a function of design nor how one transmission might "perform" better than another.

I would love for someone to educate me a little.

thanks
Matt

12 Replies

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  • ScottG's avatar
    ScottG
    Nomad
    Aug 18, 2014
    There was a time when Allison was the king of trannys. Just not so anymore since both Ford and Dodge have transmissions that are just as stout (or more so) and have all the features as the Ally (grade braking, etc). In some cases they shift better and faster as well.
    So don't get stuck on that aspect of a transmission.
  • Mark_Kovalsky's avatar
    Mark_Kovalsky
    Explorer
    Aug 18, 2014
    Quality and longevity are very important in a transmission. Function is also right up there in my book.

    All of the manufacturers have changed how their heavy duty transmissions operate to make driving easier and safer. Tow/haul mode does that.

    When tow/haul is engaged the operating parameters of the transmission change. In general terms the transmission will upshift at a higher speed, and may downshift automatically to help prevent the vehicle from speeding up while coasting. These functions first appeared around 2000-2003. Computer controls made it possible.
    Downshifting will use engine resistance to help slow the vehicle. This is especially helpful when driving downhill with a load. This takes a large load off of the brakes, so they can stay cool and be ready for when they are needed.

    Having worked on the Ford TorqShift transmission I won't agree that the Allison is superior. ;-)

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