Hard shifting after boosting.

[Trick1]

The tranny is acting a little funny and my teeth are starting to hurt.
When you first start driving the truck drives and shifts normal. But go into boost over a few psi and the tranny shifts very very hard. No problem while in the boost. But after getting off the throttle the tranny still shifts very very hard. It will keep doing this while in boost or not, until I turn the truck off and restart it. Then back to normal until I see boost again.
Any ideas.?

OH I am no tunner just trying to figure this shifting headache out.

[RedHeartbeat]

what have you added to the trans that is not stock? Personally I like to add the Transgo 46mod vacuum pressure control so that the PCM is no longer controlling shift pressures, its analog like in the old days. You need the bypass valve also, sold seperately, if you use the vacuum mod kit with a forced induction setup.

[casey23]

I had a boosted Vette in my shop that was tuned in houston.. it caused EPC to go crazy anything over 70 percent throttle? and trans would shift crazy hard till you turn the key off and restart it.. I dont think u have a nelson tune?.... First thing i would look at in the tune is the MAX LINE pressure... if its 96... move it down to 90... I have a camaro now doing the same thing.. he called me tonight.. I will make a scan on that car and report back.... possibly all in the force motor calibrations..... happens alot there....

[BlackX]

Do you have a scan tool?

Chances are when your in boost the truck is setting one of these codes
P0101
P0102
P0103

All of which have the ability to make the line pressure go MAX if they are set. Causeing harsh part throttle shifts.

Who did your tune? If your tuning it youerself check
HPTUNERS>TRANSMISSION DIAGNOSTICS>MAX LINE PRESSURE DTC
There will be enable or disable switches for each of the 3 codes mentioned.

[Trick1]

Thanks I will take a look.

[GasGuzzler]

Those MAF codes and others will command max line pressure. MAP codes will too many times.

[farmtruc]

Sent you an email Trick, we just need to return the PCS table to stock and get a vetter servo in it.

[Trick1]

Great, sent that puppy on. The servo and the new tune and I should be dialed in a little better.
So far no tranny woes just teeth hurting a little. LOL Going to start turning up the boost one this dial in a little better, and the new IC stuff is finsih, oh and get the meth reinstalled. Damm I still a day work left.
Nothing like a test truck.

[567234ta]

i have a line pressure servo for a 4l80e if you need it. the plastic clip is a little melted where you plug it in but it shouldnt matter. i had to heat up the screw to get it out and it got a little flame on the clip.