I have been trying to tune my 4L80E and have backed some of the pressure down on the 1-2 shift in the 1-2 trans pressure base table. For some reason, I still have not been able to soften the shift. Regardless of throttle positiion, RPM, or torque ft lbs it still shifts at 90psi. It also happens on the 2-3 shift.

I have attached a log and a copy of my calibration. Any help would greatly be appreciated!

 

you can add some to the shift times and/or add some TM back to the tune.. thats what i did for the time being.

 

Same here but with the 4L60. After my built tranny my shifting was a little hard for DD so I added a little to the shift times(they were zeroed out because of the build) and it softened it up a bit. After researching it a bit and taking some advice I am thinking of putting the shift times back to zero and adding TM instead. I will see what it feels like.

BTW, My performance(tow/haul) mode has zero shift times, zero TM and higher than stock pressures and it fells down right nasty but it is perfect for the track, lol.

 

POP... there went the output shaft...

 

+1. All tranny builders say USE STOCK PRESSURE. Just because it's built, doesn't mean your output shaft can handle shifts like that.

 

I had a thread just like this a month ago.I had good luck with stock shift times. Also I had a different recommendation on the efilive forum. And I think it was TM. Never tried it, trucks wrecked

 

Bite your tongues......

DD it is zero TM, lower(vs zero) than stock shift times, and stock pressures.

Performance it was higher pressures anyways since the stock tune had higher pressures in the Performance(tow/haul) mode from the factory. But i wanted it a bit harder so I raised them just a c hair.

 

Has anyone besides yourself worked on your tune? The reason I ask is because you have zero shift times and TM plus it looks like higher than stock pressures. Of course I am comparing them to my stock 4L60 tune file.

 

Thanks for the replies everyone. It seems like I may need to add a little TM and add a little bit of time to the shift times. Hmmm... I wonder if it would be easier to get a new seperator plate and have the holes drilled smaller so the PCM has more control over the shift?

A few people have worked on my tune throughout the years. The person who did the 4L80E segment swap is different than the person who has done the tuning for the last 3 years.

 

I cant see your files Jason but what area of the shift pressures are you lowering and not getting a response? What about the force motor table? Something about adding delay and TM to the dshifting seems counterproductive to me.