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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Oonrahnjay on July 01, 2012, 02:11:08 PM

Title: Transmission Gear Ratio
Post by: Oonrahnjay on July 01, 2012, 02:11:08 PM
      On the Allison transmission website, they list the gear ratios of a transmission.  There will be a table with the listings of the gears (incl. reverse) but there is a statement "Not Including the Gear Ratios of the Torque Converter".  Is there a usual ratio of the torque converter to be multiplied to the internal gearing to get the overall ratio for each gear?

Thanks,  BH NC USA
Title: Re: Transmission Gear Ratio
Post by: lostagain on July 01, 2012, 02:51:50 PM
The ratio of the torque converter is variable, because the fluid is what makes the connection from one side to the other of the converter, and it slips, a lot when you first start out from a stop, then progressively less as you gain speed.

Once the trans locks into a gear such as first and second, then the ratio is fixed and is a known figure that can be published.

That is the way I understand it anyway.

JC
Title: Re: Transmission Gear Ratio
Post by: luvrbus on July 01, 2012, 02:59:51 PM
Depends on stages the torque converter has then they have a stall ratio also, most newer torque converters are 3 stages but still a lot of the older single stage converters around don't you read here about the rough shifting on a 740 lol

good luck