I have my transmission shifting great on the up-shifts, but I'm having some trouble with the downshifts. This is on a 2010 6l80e.

It feels like whenever I downshift from 6 it will always overshoot by one gear then immediately shift up a gear. Like 6 to 3 then immediately to 4. Anyone else feel this? I'm not sure how to fix it. I tune with HPTuners.

 

What kind of shift times are you commanding and are you running tqw mgt or not?

 

The way the trans tables were setup on these 6 speed autos from the factory was not very good, they have some "shift overlap" issues. Let me guess you also get a harsh violent kind of downshift feel as well?

 

You can drop the shift times to about .20 without having any issues. Any lower than that and you Chan get some funky shifts and even cause damage because of overunning as these trannys have to have some time to coke out of one gear and go in to the next. It's a different animal than any 4 speed tranny.

 

Hi , how did you get this fixed. I am having same issue and trying to resolve for last 2 months

PS: There is no BCM in the setup , just ECM and TCM

 

Yep , harsh downshift at normal cruzing or mild acceleration.

How to fix please ?

 

You aren't having the 4-3 downshift tie up are you? Chesapeake Energy has a fleet of 2010s and 2011 3/4 tons that were constantly breaking the 4-5-6 clutch shaft. They would tie up from 4-3 on a WOT downshift from 50-60 mph and after a while would break the shaft and one even broke the hub off the rear planetary. When I say tie up it was so violent it jolted the whole truck and felt like the rear tires were going to lockup. The clutches would have hot spots from being forced to slip by the jolt. For some reason the adapts would be all over the place and resetting the adapts would make it shift smooth again. All said trucks were equipped with the most janky looking piggy back natural gas system I've ever seen. I doubt this is your problem but this is what I have seen on some trucks.

 

My truck does this with downshift tq mg off. I love the kick down it had with no tq mg, but with it off, it felt like it was gonna **** a driveshaft when I would kick down at 60 to pass someone. Any tips?