4l60e trans 1-2 shift to aggresive

[Lahmer_52]

I have a Performabuilt level 2 trans in my car and since installing the 1-2 upshift at light throttle has been way too aggressive. It feels like you're getting rear ended when it shifts. at WOT it shifts just as you would expect out of a performance transmission. My Trans tune is stock per performabuilts instructions and I have tried reducing the shift pressure modifier table at low torque loads to compensate for them mechanically increasing the line pressure in the trans. Anyone else have any other thoughts on how I may be able to soften the shifts up at light throttle?

[ns158sl]

Tune and a description of the car... 4l60 4l80 or what?

Eric

[Lahmer_52]

2001 Trans Am 228R cam with bolt ons. Transmission is a level two 4l60e from Performabuilt with a 3400 stall yank converter. The trans tune is stock per their request since the mechanically increase line pressure in the trans. I was curious how I could reduce that pressure from 1-2, other gears are fine. Is the shift pressure modifier table the right place to reduce it?

Thanks for the help

[mowton]

Reduce the UPSHIFT>NORMAL (and PERFORMANCE if you have that feature) for the 1>2 shift at the torque cells experiencing hard shifts.

Ed M

[Frost]

You can try what Mowtown said, but it maybe mechanically fixed. They can be harsh.

[Lakegoat]

On your Part Throttle Shift--Normal, start with something like 7,8,9,11,13 and so on for 1 to 2 shift and adjust your 1-2 downshift. Why is the Performance all 256? I have mine the same as normal as it is modified also. Cruise?
Desired shift time--Normal, for 1 to 2 shift can be changed to .750 to see if that will soften the shift. Why is Performance all 0 ? It looks like you want it to slam into gear.
Write this on a separate tune so you can change back easily. Drive around a while before you say it doesn't work. Good Luck.

[Frost]

On your Part Throttle Shift--Normal, start with something like 7,8,9,11,13 and so on for 1 to 2 shift and adjust your 1-2 downshift. Why is the Performance all 256? I have mine the same as normal as it is modified also. Cruise?
Desired shift time--Normal, for 1 to 2 shift can be changed to .750 to see if that will soften the shift. Why is Performance all 0 ? It looks like you want it to slam into gear.
Write this on a separate tune so you can change back easily. Drive around a while before you say it doesn't work. Good Luck.

That platform doesn't use the Performance tables.

[2xLS1]

To add to what Steve already said seeing tables populated like that in stock calibrations is a clue that those tables aren't used.

[Lakegoat]

I missed the clue. It should have BIG LETTERS----NOT USED!! for people like me.

[CareAutoLon]

Most likely just an aggressive setup in the Transmission mechanically. I know from experience having too big of a hole in the separator plate in the trans will give you an aggressive shift no matter what. The servo and 1-2 accumulator play a big role in that shift too. You may just wanna call the people who built and ask whats the simplest way to reduce how aggressive that shift is.

[Lahmer_52]

Thanks for the feedback guys, I did speak with the builder and said I could swap out the servo if tuning doesn't take care of it enough for my liking. The car is currently undergoing a 9 inch axle swap so as soon as I get that taken care of I'll give those tuning suggestions a try and see if that will soften it up a little. More to come shortly.

[Monzsta]

You could try playing with torque management. My T/A was dangerous in the rain the way it hit second, so I enabled torque management and got a seamless 1-2 shift that wouldn't upset the car. I think I ended up with it at 50%.

[carlitos2012]

hi
i have a 1998 automatic transmission trans am
and i cant figure out how to calibrate input in hp tuner tires and gear ratio.
i don't see a box for the input?
my car have 305/35/18 tire, and 4.11 gear, i know i have to divide 26.4 for 4.11 and get the magic # but don't know how to do it in 1998 cars.
any help i will appreciate. thanks

[KFXGUY]

Did you get it fixed? This is why I don’t do all of that shift kit garbage in all the 4l60’s I build. I hate when I get a unit in that didn’t last 30k miles because some “pro builder” built it and put a shit kit in it. I have to reverse all that garbage. All that harsh shift does is break parts. If you want to try and reduce it in the time some you can add in some timing retard in the torque management section in the areas that you want to reduce it. The servo is probably shimmed and doesn’t have a spring (hack way of increasing firmness) so you may not be able to do much electronically. Good luck.

[Lahmer_52]

Thanks for the info KFXGUY, its winter here in Iowa right now so waiting for things to clear off a little bit before getting it back out and seeing if the tuning tricks help out at all. I called the builder and they said they would send a new servo if I wasn't happy with how this one is working. Hoping for some warmer weather soon so I can see where I'm at with it! Ill post an update as soon as I get a chance to give it a try!