Erratic shifting on grades?

[leros]

What can be done if anything for repeated upshift/downshift on grades? I recently installed EFI Live so I could take advantage of the loss of a DPF. I am running 275/70R18 tires which are 33.25 dia. and the revs were put into the tunes (DSP5 switch).

In cruise control set at 70mph on a grade the trans will downshift then upshift then down again and so on all the way to the top. Yesterday on the same grade when it downshifted, I put it in manual mode 5 then upshifted to 6 thinking it would stay there. It downshfted by itself and it still said the trans was in 6! It would then do the same as before, down then up, down then up.

Any ideas? Should I have the TCM tune changed to spread out the 5 to 6 shifting?

 

[TrentNell]

What can be done if anything for repeated upshift/downshift on grades? I recently installed EFI Live so I could take advantage of the loss of a DPF. I am running 275/70R18 tires which are 33.25 dia. and the revs were put into the tunes (DSP5 switch).

In cruise control set at 70mph on a grade the trans will downshift then upshift then down again and so on all the way to the top. Yesterday on the same grade when it downshifted, I put it in manual mode 5 then upshifted to 6 thinking it would stay there. It downshfted by itself and it still said the trans was in 6! It would then do the same as before, down then up, down then up.

Any ideas? Should I have the TCM tune changed to spread out the 5 to 6 shifting?

TCM tuning is the only fix to make it stop hunting for gears , but to be honest if the truck is hunting so much it is because the truck doesn't have the power to hold the speed your requesting and tuning shift points wont change that .

 

[Mike L.]

What can be done if anything for repeated upshift/downshift on grades? I recently installed EFI Live so I could take advantage of the loss of a DPF. I am running 275/70R18 tires which are 33.25 dia. and the revs were put into the tunes (DSP5 switch).

In cruise control set at 70mph on a grade the trans will downshift then upshift then down again and so on all the way to the top. Yesterday on the same grade when it downshifted, I put it in manual mode 5 then upshifted to 6 thinking it would stay there. It downshfted by itself and it still said the trans was in 6! It would then do the same as before, down then up, down then up.

Any ideas? Should I have the TCM tune changed to spread out the 5 to 6 shifting?

I think 6th is too high of a gear for any kind of grade. I run over 500 hp at the wheels daley and I can't hold 6th in my truck.

 

[MACKIN]

Your avatar is to distracting to have any input on this

 

[x MadMAX DIESEL]

Also the Manual mode is not really manual, it just selects the highest gear the trans is allowed to use

 

[leros]

Also the Manual mode is not really manual, it just selects the highest gear the trans is allowed to use

Thanks, that was my next question! I guess when I cruise up grades and the trans kicks down a gear then I will use manual and keep it in 5? Or I'll try using tow/haul to see if that will hold it there.

The reason I asked this in the first place is because with the same tires, the stock tuning with DPF I didn't remember this being an issue (same hill driven every weekend). The Ford that I Lemon Lawed never did this and it had a 5 speed (actually a 6 speed) auto with 37's and 4:30 gears, I think my Ford tunes had more power than my Dmax tunes do though.