The evolution of automatic gearboxes

macabethiel · 17-10-2013, 13:04

Recent posts got me thinking about the development I have seen in Auto Shifts. The first ones I drove were the Borg Warner types of boxes used by B.M.C. Then G.M. developed the so called Strasburg box that appeared in Opels, Vauxhall and were so good even R.R. paid to use the design. DAF came up with the early CVT design that you started in Drive or Reverse and would do the same speed in either gear! Then came auto locking torque convertors. Vauxhall had Hydramatic shift then briefly the Powerglide unit that had only 2 speed ranges managing a respectable 70 mph in first! More recently the shift system involves solenoids for each gear with 7 speed being common with some 8 speed units. Then VW coming up with a twin clutch system as an offshoot of SMG development. Add race start for the top end stuff.
Wonder what will come next ?

kitchenman · 17-10-2013, 16:34

I had an old Citroen CX with 'Cmatic' gearbox, it was odd, AIR it had a torque converter, so you took off in top, if you wanted to change gear just shift with the stick, the clutch was operated by the stick

dave

macabethiel · 17-10-2013, 18:35

Yep the NSU rotary engined RO80 had a similarish system. There was a microswitch in the gear knob that activated an electric clutch.

17-10-2013, 13:04	#1
macabethiel Senior Member Join Date: Aug 2008 Location: Derby Vehicle: Freelander & Jeep GC 3.0 Posts: 4,416	The evolution of automatic gearboxes Recent posts got me thinking about the development I have seen in Auto Shifts. The first ones I drove were the Borg Warner types of boxes used by B.M.C. Then G.M. developed the so called Strasburg box that appeared in Opels, Vauxhall and were so good even R.R. paid to use the design. DAF came up with the early CVT design that you started in Drive or Reverse and would do the same speed in either gear! Then came auto locking torque convertors. Vauxhall had Hydramatic shift then briefly the Powerglide unit that had only 2 speed ranges managing a respectable 70 mph in first! More recently the shift system involves solenoids for each gear with 7 speed being common with some 8 speed units. Then VW coming up with a twin clutch system as an offshoot of SMG development. Add race start for the top end stuff. Wonder what will come next ?

17-10-2013, 18:35	#3
macabethiel Senior Member Join Date: Aug 2008 Location: Derby Vehicle: Freelander & Jeep GC 3.0 Posts: 4,416	Autos Yep the NSU rotary engined RO80 had a similarish system. There was a microswitch in the gear knob that activated an electric clutch.

17-10-2013, 16:34	#2
kitchenman Senior Member Join Date: Jan 2011 Location: Essex Wescliff Vehicle: maverick 1994 2.7 TD Posts: 1,278	I had an old Citroen CX with 'Cmatic' gearbox, it was odd, AIR it had a torque converter, so you took off in top, if you wanted to change gear just shift with the stick, the clutch was operated by the stick dave