99 L31/4L60E - tranny programming

[Tim240Z]

I have a 99 suburban L31 and 4L60E in my 71 Cheyenne20.
I also have TunerCat, so I have full and unadulterated access to the PCM.
What I need to know is this:
What parameters should I edit to increase shift firmness and TC lockup speed (it appears to be locking/unlocking at ~40mph and is annoying as heck&#33.
Also, the other day on the freeway, at about 60MPH, I hammered the accelerator and it downshifted, but just free-revved (like it was in neutral) until I eased off the gas a bit. I will install a shift kit if necessary, but I'm sure that somehow increasing line pressure via the PCM should do the trick, no?
There are so many different tranny parameters in TunerCat, i'm not sure what to change....

Thanks,
Tim

[RedHeartbeat]

Sounds fishy to me. Your trans/engine shouldn't free-wheel during a downshift. Might check your torque convertor lockup settings to see if it's set to not lock during shifts. That trick works great in drag racing but not worth a damn on the road.

[Tim240Z]

The trans settings are still factory, so maybe the trans is going south?
It had 62k miles on it when the donor gave it up to my truck.....

[jobberone]

you can specify a speed for lockup. If that doesn't work set it to default and reprogram it; ie reset it. If that doesn't work try this guy on this forum:

www.pacificp.com/forum
PSWired


Here is another way to get him:

http://www.pswired.com/95silverado/silverado.htm