c4 2-3 flare under Low power only

my c4 on my 302 has a 2-3 flare only under heavy power. Is it possible that this is a modulator issue? i recently rebuilt the c4 (less than 1000 miles ago) and put in a transgo shift kit. the flare has not existed since the beginning. It only happens under low power, when i am stepping on it it shifts perfectly. I do not have an inch-lb torque wrench so i cannot be sure what the band adjustment is. I have ordered a green stripe modulator as mine appears to be bad (vaccuum hose has oil in it and the nipple on the modulator had some drip off of it). Am i missing anything or could this be caused by my modulator? also my fluid is fine.


i should add that although i do not currently know the torque on the front band it was torqued to spec (and then backed out 1 3/4 turns) when it was originally rebuilt

 

More than likely an issue with the modulator, that's what mine did. Also you can use a ft-lbs torque wrench to adjust the bands. 120 in-lbs=10ft-lbs.

 

Thanks for the quick reply. I'll get the modulator tomorrow and I'll report back with what happens

 

I've never had a issue adjusting bands till snug then backing off the specified amount...

 

Kind of misleading.
One place you say low power next is under heavy power.

 

• Sonnax "C-ratio" Aluminum billet 2-3 shift servo
• Performance Automatic PA 26411 C4 Shift Servo
• TCI 523005 Billet Servo

I installed the Sonnax. No problems & easy to install

 

Thanks! ill check it out.

Oops! i meant to say low power in that first sentence... i proof read it too

 

i have an A servo on there. is that not enough do you think?

 

Probably not. But, It is difficult to say - if every other possibility has been explored (modulator, vacuum leaks, bands, etc); then I'd say a definite yes. Remember that in most cases, automatics were (are) designed for SSSSSmmmmoooothhh shifting (so mom, pop and baby boo-boo) don't get their necks cracked.

Mine with the C code, shifts firm (but not back braking), and never flares - even going up a hill.