Author Topic: Semi automatic transmission  (Read 2883 times)

Offline richard5933

  • Hero Member
  • *****
  • Posts: 3963
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 Custom Coach "Land Cruiser" (Sold)
1964 GM PD4106-2412 (Former Bus)
1994 Airstream Excella 25-ft w/ 1999 Suburban 2500
Located in beautiful Wisconsin

Offline Oonrahnjay

  • Hero Member
  • *****
  • Posts: 3474
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

  • Hero Member
  • *****
  • Posts: 1814
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.  :(

Offline Iceni John

  • Hero Member
  • *****
  • Posts: 2164
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.
2kW of tiltable solar.
Behind the Orange Curtain, SoCal.

Offline mikke60

  • Full Member
  • ***
  • Posts: 180
  • Out with old, in with the not as old
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

  • Hero Member
  • *****
  • Posts: 7101
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

  • Hero Member
  • *****
  • Posts: 2011
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

  • Hero Member
  • *****
  • Posts: 9255
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. 1985 Kenworth 40ft Super C with garage. '77 AMGeneral 10240B; 8V-71TATAIC V730.

Offline Brian Diehl

  • Hero Member
  • *****
  • Posts: 1180
    • www.brihil.com
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.

 

SimplePortal 2.3.7 © 2008-2024, SimplePortal