Anyone have a 4L80E program?

[Taz]

Hello Telco,

Shift time and shift pressure help keep the transmission from slipping. Shift times in the 0.150 to 0.300 second range are a "ballpark" of what generally works well in 1>2 and 2>3 shifts. Shift pressure I ramp up fairly quickly - to prevent slippage.

Slamming shifts may be caused by too much pressure, too soon - but are usually caused by insufficient TR (torque reduction). If you have the TR "zeroed out" it will probably shift far too firmly. Reducing shift pressures simply because you want TR set to "0" puts the transmission at risk, and removes a tuning variable from the table.

Try increasing TR to smooth out your 2>3 shift.


Regards,
Taz

[Telco]

I've got some in there now. I'll add some more in and we'll see what happens then. Thanks.

[Telco]

I added more pressure and more torque management, and adjusted the shift speeds per your recommendation. It made things quite a bit different. But, it did smooth the 2-3 shift out quite a bit. We'll see what a few more hits does with it, thanks.

[Telco]

I've done the above, and now have a rougher shift. Interesting note though, I also noticed that the truck seems stronger with the higher pressures which leads me to believe that lowering the pressure only to improve shift feel was also causing me to lose power in the trans due to slippage. So, pressure too high causes banging shifts, pressure too low causes loss of power transmission to the rear wheels making the engine feel weak. I'm going to try increasing the shift speed time a bit more and add a bit more torque management at the bottom.

What PIDS I would need to watch to tune this correctly?

[joecar]

Include at least these: GEAR, SHIFTLAST, TFMPRS, TRQENG, VSS, RPM, TFT, TCCMODE, TCCSLIP.

Yes, do not let the trans slip... set the shift pressures a little higher and the shift times as Taz said above, and then play with torque reduction to tune the shift feel... you want a firm shift with being jerky.

Make sure your MAF and VE tables are correct to ensure that the in-gear pressures are sufficient to prevent slipping.

[Telco]

Heh heh... I've got an Innovate LC1 in a box right now waiting for installation, but I'm also working 12 hour shifts 6 days a week and have only the truck to get around in. Right now I have just about enough time to tweak the program based on the drive to work and back, then slap the program in and try the next day. If I can ever get another vehicle or get some time off I can get it in and get do the autoVE thing. Until then I'm using a stock 4.8L table, best I can do at the moment. I'll set up a scan using those parameters and see what I can turn up. I've also picked up a factory manual for the truck so I've got access to what the pressure should read. Thanks.

[Telco]

Found why I wasn't getting anywhere adjusting for the 2-3 shift. Field D0706 had VERY high numbers where D0704 and D0708 didn't. I copied this field from another 4L80E program that didn't have such high numers (as high as 45) and now all of a sudden the 2-3 shift isn't killing me. Now it's giving me a hard shift suitable for the dragstrip rather than the hard jerk suitable for tearing the trans mount out.

I also fiddled with the shift speeds, by pulling up a Corvette program and using the Speedo Calculator, and used the Shift Point Corrector to match them to my setup.

Thanks to the folks here, I'm getting there.

[joecar]

Glad you found it thanks for posting back.

[Telco]

I'll do more than that, once I work it out so it shifts properly I'll both post the program here and shoot it over to HoldenCrazy although I'll wait on him until I get the engine programming done as well.

[Telco]

All righty folks, I'm to the point now that things are smooth, and I think I'm ready for fine tuning. I understand that the more pressure the better so long as I don't have so much that I'm breaking parts. Question is, is there a max amount of torque management I need to be using? How much is too much? I've been going off the assumption that 35 percent is the max I need to use.