Allison Transmission

[Chuck B 2004 Windsor]

Keep in mind that the Allison Transmission has a torque converter that comes into play when establishing driving habits.  The torque converter will  be locked and unlocked depending on how the transmission shifts.  Chuck B

[Jim McGarvie]

I find this discussion quite interesting, and I am curious how much of it applies to our little 5-speed Allison 1000 with the 5.9L ISB engine.

I have experimented a bit with the Econ mode, but couldn't detect a significant difference so I don't use it. On uphill grades I tend to downshift manually when I decelerate to about 1900 RPM, which jumps the RPM up to around 2500. The engine seems happier.

[Jim McFarland]

How interesting. I guess I don’t understand why there is such a lag time from when you step on the fuel pedal to the time the engine starts revving up and you start moving. Do all coaches with a toque converters have that issue. Sorry it appears that I have more questions than answers. 

[Ivylog]

The Alison 3000 & 4000 6 speed transmissions only use the torque converter in 1st & 2nd gears. Starts in 1 unlocked then the torque locks, shifts to 2 unlocked and then the torque locks before shifting to 3 locked, 4 locked, 5 locked which is a overdrive & 6 locked a double overdrive.  In some ways it’s a 8 speed tranny.
A turbo Diesel engine is slow to get going because the turbo isn’t doing much until you get above 1400 rpms which takes awhile even with a torque converter that lets it increase rpms quicker.