TCM H0105 speed sensor pulses per mile doesn't match ECM H0101 vss pulses per mile

[mtomac]

In a stock Allison 5 speed TCM H0105 is 4000 and in the Duramax LB7 ECM H0101 is 101605. Why don't these two match?

Also why is the TCM final drive ratio H0103 4.10 when all Duramax truck have 3.73 gears

[THEFERMANATOR]

Because that is how ALLISON set them up. There is no reason to change them as it will change hundreds of other tables you cannot see or modify. ALL of the tables reference these tables, and even small changes can REALLY change how the TCM reacts. It can render grade braking inoperable, or make it come in when it shouldn't, and changes ALL of your shift points(and timing).

[killerbee]

I am wondering if anyone has pinned down the loss/change of grade braking to a specific table change.

[DURAtotheMAX]

I am wondering if anyone has pinned down the loss/change of grade braking to a specific table change.

x2. I wish we had access to the grade braking tables/algorithms/logic..

[THEFERMANATOR]

x2. I wish we had access to the grade braking tables/algorithms/logic..

Would be nice. Then maybe we could figure out why it tends to work AFTER you needed it to come in. Just got back from the mountains, and it was REALLY annoying having it finally drop into grade braking at the bottom of a pass after my brakes were hot.