New Allison Software

[David Brady]

With the upgraded tranny software the economy mode is preserved.
With economy enabled the shift points are lowered by 300 rpms. W/o
economy enabled the shift points are such that the engine rpms are
at or above 1750rpm, within reason of course. With economy enabled
the shift points fall down as low as 1400 rpms. The default is still
performance; economy must be selected by the user, and there is a clear
performance difference to them. I think what happened is that many
customers complained about the shift hunting and allison has produced
a fix. Trust me, the overall performance, acceleration in non-economy
mode, is profound. The "fee" for the hunting fix is quite worth it. Plus,
the shift quality is utter silk. One must truly look at the tach to even
notice
them.

David Brady,
'02 LXi, Smokey
Va

Tom McCarthy wrote:
> 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
>>
>>
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