Author Topic: Semi automatic transmission  (Read 736 times)

Offline richard5933

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Semi automatic transmission
« on: March 16, 2018, 11:01:07 AM »
Any of the buses in the US ever use something like this? Don't think I've ever seen one.

https://www.youtube.com/watch?v=GE6p-KffdTo
Richard
1974 GMC P8M4108a-125 (Current Bus)
1964 GM PD4106-2412 (Former Bus)
Located in beautiful Wisconsin
KD9GRB

Offline Oonrahnjay

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Re: Semi automatic transmission
« Reply #1 on: March 16, 2018, 12:22:29 PM »
  Any of the buses in the US ever use something like this? Don't think I've ever seen one.  ... 

     I've seen one.  In fact,  I own one!
Bruce H; Wallace (near Wilmington) NC
1976 Daimler (British) Double-Decker Bus; 34' long

(New Email -- brucebearnc@ (theGoogle gmail place) .com)

Offline HB of CJ

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Re: Semi automatic transmission
« Reply #2 on: March 16, 2018, 06:54:59 PM »
In about 1970 I got to test drive a demo Crown Supercoach school bus which had an air shift shifter on the dash.  Short lever.  Still had a clutch pedal.  The transmission was air shifted.  Did not work so well.  Much clashing and noise until one got the hang of it.  :(

Online Iceni John

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Re: Semi automatic transmission
« Reply #3 on: March 16, 2018, 08:09:56 PM »
Semi-auto gearboxes were the most common bus transmission at one time in England.   Leyland and Bristol used them on most of their buses  -  here's a preserved Leyland Leopard being shifted correctly:   https://www.youtube.com/watch?v=oKKKgjzKcsw   The shifters were either air-operated or electro-pneumatic, making the distinctive hiss during every shift.   It's a pity they never caught on in this country:  they seem to me to be ideally suited for buses.   I have fond memories of Leyland Tigers and Bristol REs being hustled along narrow country roads with the driver expertly shifting to keep the engine in its sweet spot.

John
1990 Crown 2R-40N-552 (the Super II):  6V92TAC / DDEC II / Jake,  HT740.     Hecho en Chino.
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Offline mikke60

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Re: Semi automatic transmission
« Reply #4 on: March 17, 2018, 04:40:21 AM »
seems to shift it as if you would an older truck without a syncro tranny. using the engine rpm,s to allow for smoother up shifts as well as downshifting.

Offline chessie4905

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Re: Semi automatic transmission
« Reply #5 on: March 17, 2018, 06:08:17 AM »
Eaton makes semi-automatic transmissions and automat versions. Someone on here had one a while back. Don't know if he's on here anymore.
GMC h8h 649#028 (4905)
Pennsylvania-central

Offline CrabbyMilton

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Re: Semi automatic transmission
« Reply #6 on: March 17, 2018, 02:52:39 PM »
Then people wonder why at least over here ALLISON is king.
More trouble than it's worth with those clutchless manuals.

Offline TomC

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Re: Semi automatic transmission
« Reply #7 on: March 17, 2018, 08:12:42 PM »
There are two types of transmissions in buses and trucks. Fully automatic like the Allison (3000, 4000, TC-10), and the fully automatic autoshift type. Second is full manual transmissions. Good Luck, TomC
Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.

Offline Brian Diehl

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Re: Semi automatic transmission
« Reply #8 on: March 19, 2018, 08:31:58 PM »
I'm running an Eaton Autoshift transmission behind my Cummims ISM.  My tranny is the version where you have to use the clutch to get rolling, but once rolling all shifts up and down are automatic and do not use the clutch.  I find it to be perfectly adequate.