New Allison Software

[Tom McCarthy]

Along the same line, I learned at FMCA that the Allison software
defaults to a high RPM/Speed shift point for better performance in
acceleration. On mine, the shift point from 5th to 6th is right
around 60 mph. The tranny constantly shifts back and forth on
inclines.

If you push the Mode button, the shift points are lower and,
therefore, more economical for driving distances. The 5th/6th shift
point is 10 mph lower. No more hunting between the two at highway
speeds. So, unless you are at Maxton, they recommended pushing the
Mode button every startup to use the lower shift points.

Why is it this way? Allison actually had it reversed at first.
They received so many complaints from RV sales people that the
diesel engines did not rev high enough to impress buyers and the
speed off the line was too slow (unofficial inside story, not
verified and probably will not be confiremd by Allison), that they
acquiesced to the market. Allison will change your tranny to
default to the "economic" mode for a fee. From David's description
of his new software version, they might have done that as a default.

Tommy "Two Shoes" McCarthy
Poway, CA (San Diego)


--- In WanderlodgeForum@yahoogroups.com, David Brady
wrote:
>
> Folks,
>
> While at Smith Power Products in Salt Lake City, Ut,
> I had the HD4000 tranny reflashed with the latest software.
> I was running 0C00ABF008N and upgraded to 0F00ABF005S.
> The first 4 digits are the major number of the software. From
> 0C00 to 0F00 reflects a 3 level later revision. The last 4 digits
> are the minor number of the software release. ABF means that
> identifies the 4000 series transmission. My complaint with revision
> 0C00 was that it hunted for the proper gear when ascending
> a hill. She cycled repeatedly thru downshifts and upshifts 'till I
> tired of it and hit the down arrow to lock her into the proper
> cog. Not so anymore, with 0F00 she downshifts once and stays
> there, and the shift points keep the engine at 1750rpm or
> above. Very pleased! Another benefit is that the shift quality
> is much improved. The tranny learns how to shift by measuring
> torque on the input and output shafts, and it changes the quality
> of the shift by varying the pulse width of the hydraulic fluid into
> each clutch pack. I can no longer feel the downshifts they are so
> smooth, the only indication is that the rpms on the tach change.
> Very pleased! We also did an a engine oil (synthetic) and tranny
> oil (transynd synthetic) lab analysis - everything checked out
> well. 70K miles on the LXi and she's just breaking in.
>
> David Brady
> '02 LXi, Smokey
> Va
>