8spd downshift indecision @ ~60% throttle

Black1500Ram · Sep 11, 2022

Hi Guys,

Have any of you experienced “indecision” from the 8spd trans when making a sudden acceleration (think making a light or on ramp) at less than 100% throttle, usually 60-80% throttle?

Basically my trans will down shift, then realize “oh that’s not enough” and downshift again, in order to meet what it thinks my acceleration needs are based on throttle position. (All very smoothly)

Since the trans learns does anyone have an understanding of the trans mapping?

I know there’s nothing wrong with the trans at all, im just trying to figure out how to get it to learn (or for me to learn how much throttle to give it) to get it to go straight from 6 to 4 (for example), rather than 6, 5 oh no that’s not right, 4.

All that indecision is basically dead acceleration.

And I can already hear y’all saying “just mash the throttle then” lol.

Appreciate any help.

James

Wild one · Sep 11, 2022

Black1500Ram said:
Hi Guys,

Have any of you experienced “indecision” from the 8spd trans when making a sudden acceleration (think making a light or on ramp) at less than 100% throttle, usually 60-80% throttle?

Basically my trans will down shift, then realize “oh that’s not enough” and downshift again, in order to meet what it thinks my acceleration needs are based on throttle position. (All very smoothly)

Since the trans learns does anyone have an understanding of the trans mapping?

I know there’s nothing wrong with the trans at all, im just trying to figure out how to get it to learn (or for me to learn how much throttle to give it) to get it to go straight from 6 to 4 (for example), rather than 6, 5 oh no that’s not right, 4.

All that indecision is basically dead acceleration.

And I can already hear y’all saying “just mash the throttle then” lol.

Appreciate any help.

James

Disconnect the negative battery cable,step on the brakes for a minute to drain the system,then take it out and drive it like you stole it,might help,might not,but worth a try,you can also get in the habit of manually downshifting it to James

joesstripclub · Sep 13, 2022

I have had that happen on occasion. We probably think our foot is steady on the throttle but it likely adds a bit more throttle when we dont feel like we are accelerating fast enough. The transmission was making that first shift then realized oh he wants one more. I notice after I've towed that the transmission shifts super quick and is a bit more aggressive for some time. Maybe try driving your truck with tow mode turned on? Or like you said mash it a bit harder lol.

RedSRT4Me · Sep 14, 2022

Black1500Ram said:
Hi Guys,

Have any of you experienced “indecision” from the 8spd trans when making a sudden acceleration (think making a light or on ramp) at less than 100% throttle, usually 60-80% throttle?

Basically my trans will down shift, then realize “oh that’s not enough” and downshift again, in order to meet what it thinks my acceleration needs are based on throttle position. (All very smoothly)

Since the trans learns does anyone have an understanding of the trans mapping?

I know there’s nothing wrong with the trans at all, im just trying to figure out how to get it to learn (or for me to learn how much throttle to give it) to get it to go straight from 6 to 4 (for example), rather than 6, 5 oh no that’s not right, 4.

All that indecision is basically dead acceleration.

And I can already hear y’all saying “just mash the throttle then” lol.

Appreciate any help.

James

The truck acceleration is based on throttle position percentage. 30% or less will stay in the "normal" ECO shift patterns. Somewhere after 40% will get the truck to downshift like your requesting. Something near 70-80% will get two gears.

Also consider braking gets the truck to downshift as well to aid stopping. Braking has another set of maps separate from acceleration.

However, brake it hard enough to downshift then mash the gas could throw you for a surprise depending on what tune is being ran. It can also replicate the shift hunting as well.

crazykid1994 · Sep 14, 2022

I hate to be that guy but my gmc van has the 6l trans. That thing sucks with shifting. Basically feels like it drops to neutral until it hits the gear and then slams into gear basically lurching the van like dropping the clutch. And gmc said that was normal. You could always try doing a relearn and drive it a bit hard as that will make it downshift more frequently. Disconnect the battery for an hour.

Black1500Ram · Sep 14, 2022

crazykid1994 said:
I hate to be that guy but my gmc van has the 6l trans. That thing sucks with shifting. Basically feels like it drops to neutral until it hits the gear and then slams into gear basically lurching the van like dropping the clutch. And gmc said that was normal. You could always try doing a relearn and drive it a bit hard as that will make it downshift more frequently. Disconnect the battery for an hour.

I did this and have been driving a bit more aggressive from stops, but super chill when cruising and honestly it’s night and day different. I’m thoroughly impressed.

8spd downshift indecision @ ~60% throttle

Black1500Ram

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Wild one

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joesstripclub

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RedSRT4Me

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crazykid1994

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Black1500Ram

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