4L80E 4-2 downshift??
#1
4L80E 4-2 downshift??
I need a little help here guys. Recently helped a friend swap his 60E for an 80E, did the segment swap, and adjusted his tune for shift points & firmness, etc. But the transmission does one thing that he does not like.
If it's in 4th gear with the converter locked, and gets on the throttle aggressively or goes WOT, it unlocks the converter, then shifts to 3rd, then a second later shifts into 2nd gear. It doesn't seem to matter what I change, I can't seem to make this thing go straight to 2nd gear from 4th.
Is this just the way it is?
If it's in 4th gear with the converter locked, and gets on the throttle aggressively or goes WOT, it unlocks the converter, then shifts to 3rd, then a second later shifts into 2nd gear. It doesn't seem to matter what I change, I can't seem to make this thing go straight to 2nd gear from 4th.
Is this just the way it is?
#2
TECH Fanatic
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Sounds like an issue with the shift tables. What changes from stock did you make? Did you only adjust WOT shift speeds/RPMs or the partial as well? Also have you logged the truck while doing this? What does the TPS% look like during these shifts? Is this a DBC or DBW truck? Also what does your TPS enable full throttle % look like? Something seems very odd here.
#4
Mod with training wheels
iTrader: (16)
When driving in OD, it has to logically command 3rd and then sample the TPS, RPM and VSS in order to determine if it can and still needs to downshift. Whether or not the transmission responds promptly is all in the transmission... Fluid circuits react a little slower than electrical circuits
The 6 speed is designed to skip gears though. Rowing down through all those gears would be cumbersome. I haven't seen any 6 speed tune files that have the parameter that controls it, but I assume the TCM uses some minimum load transient that enables the transmission to skip gears to get the vehicle up and moving quicker. Obviously the 80e is too simple for that, nor is it really necessary with only 4 gears.
The 6 speed is designed to skip gears though. Rowing down through all those gears would be cumbersome. I haven't seen any 6 speed tune files that have the parameter that controls it, but I assume the TCM uses some minimum load transient that enables the transmission to skip gears to get the vehicle up and moving quicker. Obviously the 80e is too simple for that, nor is it really necessary with only 4 gears.
#6
Launching!
The 6 speed is designed to skip gears though. Rowing down through all those gears would be cumbersome. I haven't seen any 6 speed tune files that have the parameter that controls it, but I assume the TCM uses some minimum load transient that enables the transmission to skip gears to get the vehicle up and moving quicker. Obviously the 80e is too simple for that, nor is it really necessary with only 4 gears.
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#8
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What jake said! its supposed to do that. the trans may be a little lazy causing it to be drug out, but thats what they do. i almost always downshift using my tow haul button (setup in tune) before i do a wot pull considering a downshift is a very harsh action when making good power.
#9
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i cant feel mine dropping to third then 2nd.. but it sure does take a long time to go from 4 to 2..
So i setup my tow haul button to go to the lowest gear possible just for whatever reason.
>47 and it drops to 1st
>85 and drops to 2nd
No waiting and it hits hard.
So i setup my tow haul button to go to the lowest gear possible just for whatever reason.
>47 and it drops to 1st
>85 and drops to 2nd
No waiting and it hits hard.