Tranny shifts HARSH if I accelerate SLOW?

[gmrulz4u]

My 1-2 Upshift is quite harsh/delayed if I accelerate slowly or with regular acceleration. If I go HARD on the throttle and accelerate FAST, it shifts good!!

 

Now, the tranny is the oh so "picky" 440-T4(4T60). This tranny uses a Vacuum Modulator for shift firmness, and the TV cable for timing. So, I'm thinking that there's probably more vacuum under slow acceleration, and less under high throttle, right?

 

Any ideas?

 

THANKS:)

 

PS the car is an 89 Cutlass Supreme 2.8 MPFI and ALL other shifts are good(2-3, 3-2, 2-1 etc.)

[nriesen]

have a look at the vaccuum lines going into the trans, CIX46 actually pulled the vacuum line off of my trans to make the shifts firmer, and now my car shift the way you described, so i would check the vacuum hoses and see which one is junked

[Robby1870]

yeah, theres more vacuum at low rpms, and very little at high rpms. Check the vacuum lines running to the tranny, if they are fine, take the vacuum modulator out, and see if there is tranny fluid in it.

 

Robby