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Author Topic: HT70  (Read 3020 times)
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Posts: 28

« on: August 14, 2006, 06:56:26 AM »

Hey all,

i am looking to bid on a fire truck on ebay. The Fire Dept says the motor is an 8v71 and the Tranny has a stamp on it that says "HT70"
I am wanting to change my 5 speed spicer to an Auto. I have a model 10 with a 6v92. Will this HT70 work well with a 6v92? Thanks for the help

Thanks, Robert at www.tamihall.com
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« Reply #1 on: August 14, 2006, 07:29:47 AM »

They're missing a number.  Should be a HT740 for a 4 speed, or a HT750 for the 5 speed.  Can use it on any engine with the same bell housing.  Good Luck, TomC

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.

« Reply #2 on: August 14, 2006, 07:31:18 AM »


Ok, first off.  When you note you've got an HT-70 ... everyone will tell you you're wrong ... you;ve got the wrong number, etc.  You are NOT crazy, you DO have the right number.  When I phoned Allison asking about my "HT-70" with my "8V71" in my "MCI, MC-8" ... they told me I was mistaken and was missing a number.  After my repeated, "No, it's an HT-70." ... It took in an in-person, "Wow, no sh*t ... never saw that before."  I had at least 3 or 4 mechanics from Allison looking at the bus.  One took it for a drive with me in the buddy seat, checking it out.  SO, no ... you got the right number.  Smiley

That said, I would avoid using the HT-70 transmission.  This mid-70's (evidentaly) Custom Coach spec'd transmission was most commonly found in off-road dump trucks, fire engines and the rigs which push the airplanes back from the airport terminals.  Those vehicles aren't so much interested in a smooth shift.

This 6-speed auto is a hard shifting transmission until you learn its nuances ... and is NO longer supported by Allison.  The Allison dealer suggested that "IF" I had transmission problems down to road, to swap it with a HT-740, or try and find a decent HT-70 in a junk yard for parts.  They were kind enough hoever to provide certain important photocoped pages of the manual on it, as I could not find anything elsewhere on it.

The HT-740 is likely more common and user friendly for your application.

Good luck,
Jerry H.

« Last Edit: August 14, 2006, 07:38:52 AM by JerryH » Logged
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