So whats the safest way to guide the auto trans to shift when you want it to?
My truck has stock injectors and doesnt have any chip that I am aware of. I start to let out when my EGT's get to about 1200... rarely do I let them hit 1250.. and If I do, its only for 10 -15 seconds. I'd like to understand how to do what you described below, where you know a grade is coming, so you downshift and pick a speed like 55mph that you know you can safely hold through the grade. This sounds like a good way to approach these types of situations.
I always use overdrive, unless the grade dictates otherwise. Sounds like maybe you could have down shifted on the described situation. Depends on a lot of different circumstances, length of the grade, how close to the top, weight of load, etc. EGTís dictate some of what to do. If they are too high itís let off some or downshift. A truck with stock injectors and tune will be hard to get the egtís too high. We have some fairly steep grades here in NE Iowa, on some I down shift at the bottom of the hill before the motor even begins to lug, pick a speed (usually 55) and hold it there till the top. One thing I have learned with my 3.55 geared truck, waiting too long to down shift is the wrong thing to do. The 4.10 auto truck is much more forgiving.
1996 f-250 XLT 4x4 7.3 - 215k miles - bone stock, for now...