Adaptive Shift Times 4l80e + HD2

[2500ak]

My truck has a 4l80e, and a few months ago I got bored with it and installed a Transgo HD2.


I bored the sep plate for .086 which is HD shifts.

I like the shifts, they're better than stock, and I've heard that .097 is too firm for a heavy truck.


Now I want to have a custom tune assembled for the truck, but I want to make sure its done right the first time, as shipping anything to Alaska is a pain.

In theory disabling adaptive shift should make it shift more firmly and more consistently.

Has anyone actually tested this, can anyone describe the effect?



I want to decide if it would be better to have the shift times lowered, or disabled.

[Lextech]

I have a 4L80e with the HD2 shift kit also. I disabled the adaptive shift at the same time as the kit install. My thinking was---Why let the PCM try to figure out and soften the shifts to negate the shift kit. It has been that way for 3 years and I'm happy with it.

Jeff

[2500ak]

What did you drill the sep plate for firm or HD?

My current idea is to zero out the tables in regular mode, then have them set to .2XX-.300 in the performance (TH) mode.

I can't see HP in the 300-350 range at the crank damage a 4L80e unless its really shifting hard, so let it shift somewhat hard.

[Lextech]

I drilled it for HD. I am quite pleased with the shifts.

Jeff

[Chevy366]

On mine , I left everything stock except the shift times (adaptive shift) , zeroed those out .
When I put the kit in , I had already had some tweaking to the trans tables (TQM , L pressure etc..) and after the install was way to much , trans kits work best at factory settings because that is what they are intended to recalibrate with the mods to the trans .

[2500ak]

Yeah I know not to have the pressures modified, the higher pressure boost valve causes the pressures to be magnified and whatnot.

I'm just worried it will shift too slowly. It feels about stock right not unless I get on it then its much faster of course. Probably an irrational fear.

On the 2-3 I almost wish I'd drilled for firm, but then again I've heard that isn't a good idea.

[2500ak]

I was just thinking about something, and I'm wondering if anyone has any insight.

Is the adaptive shift a limit that the PCM tries to reach, or a maximum shift time before which the PCM will begin to add line pressure?

If its a limit then adaptive shift may perhaps be making my shifts less crisp, on the other hand if its just a maximum time then zeroing it out may do nothing at all. In which case the only solution would be small increases in pressure or more likely just pulling the VB and punching out the holes.

It's firmer than stock yes, but not quite firm enough for my liking.

Ant thoughts?

[L31Sleeper]

I believe adaptive shift lowers the shift time to prevent excessive slip.

[slow67]

On the 2-3 I almost wish I'd drilled for firm, but then again I've heard that isn't a good idea.

You can pretty much go 2-3 as hard as you like. Its the 1-2 you have to worry about killing the sprag.

[Chevy366]

I did firm at first , bad idea , way to hard , 1-2 chirp every shift , 2-3 with firm felt like someone running into the back of the truck even when the trans was shifting at 90+ mph .
1-2 was fun but got old after a while . I shot peened the holes and reduced the size to the softer setting .
With the new cam , have to be careful even with the softer setting , it can still break the tires loose on 1-2 shift .