Raising shift point questions.

mike diesel

I'm alright.
Sep 6, 2012
4,005
0
36
SLC, Utah
Ive ventured into a totally new area of the dmax world which I probably shouldnt have...tuning.

I dont really have much interest in tuning the ecm as much as I do the tcm. So yesterday I decided to try it out for myself. All I wanted was some 3700 rpm shifts with the converter slip function disabled. So thats exactly what I made and it seems to work well...atleast I think.

The ecm side of it should all be taken care of already from my tuner because it does, from what I can tell on the tach, shift at right around 3700 rpm and from the reading ive done it looks like if the ecm is not set up for it, you wont have raised shifts.

So my main question is, when adjusting the shift points do the WOT mph shift and WOT rpm shift need to match perfectly for it to "safely" make the 3700 rpm shift? Or can you set the mph shift faily low but leave the rpm shift at 3700 rpm and still achieve the 3700 rpm shift since the mph portion of it will be met fairly early? Seems like the TCM needs to have TP%, mph and rpm met for it to make the shift.

I did not mess with any shift timing or anything like that so if im correct then I dont see how I could hurt the trans if all I changed was WOT Shift rpm and mph. Am I correct in assuming this? Of course being my first tune ever I am still unsure if it is safe or not.

Im a complete newb at doing any tuning...gotta learn somehow so let the criticizing/bashing begin...:D
 

CaptPhil

Active member
Sep 10, 2011
1,012
0
36
Delaware
I don't change the mph. It shifts perfectly fine at the exact rpm I set in the tune.

Kory didn't change the mph either.

If you get a big defuel at wot shifts you may need to adjust both the tliq table in the ecm and the torque reduction table in the tcm. All I did with those was to copy the stock 3200 rpm values and extend them out to the end of the table.
 

AKlowriderZ71

New member
May 14, 2012
719
0
0
Wyoming
To what rpm is the factory valvetrain still safe? I will never need to know for my own truck, but you guys have me wondering.
 

andy-stevenson

New member
Jul 7, 2013
838
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What do the dotted and solid red lines on the tachometer indicate then? Solid is while grade braking and dotted is?