C6 lazy shifts

Hey guys I just joined this forum and I hope to help when I can but right now I am in need of some info/advice on my C6 trans. I have a C6 that has been rebuilt with quality parts that just seems lazy when it goes from 1-2 then 2-3. I originally built this trans in '91 but it only has about 20 miles on it due to the vehicle sitting( in a closed warehouse). This condition happened even when it was fresh from the rebuild. It had a TCI rebuild kit installed but we went with Raybestos clutches(blue?), really a basic rebuild from what I remember. I installed the TCI shift kit but I noticed the B&M shift kit was way more positive in the shift areas. I've since purchased and installed a B&M transpak competition level shift kit(3 levels), for the harshest shift possible and if too harsh I thought I could bring it down a notch. It still was lazy, so I removed the modulator and measured the pin which was within spec.( I don't remember measurement). The trans will up-shift and down shift by itself fine while driving(except for the lazy shifts) and it will go into reverse fine. There is no shudder, it goes into gear instantly when shifted to "D" or "R", it doesn't flare at any of the shifts, it just feels like a grandma's car when it shifts. I know it has a "P" servo but don't know about the lever. I have adjusted the band and it screwed in a tick more than it originally was after adjustment, haven't had the car out yet(need to rebuild carb). I plan on rebuilding the carb soon so any help will surely be appreciated. Thank you, Todd

What color modulator does it have? Find a black stripe one if you can.... and change it if yours isn't black. Some modulators have a screw where the vac hose goes on....put a small screw driver in it and turn it clock wise about 3/4 turn and see if tghat helps. Good luck....George

Seems you have a good selection of parts. Time for a pressure gauge on there to see what is going on.

Thanks guys, I do appreciate your replies. g612gr, the modulator is a black stripe, I replaced the original black stripe modulator that was in the trans after the rebuild to check to see if that was the culprit of my problems. I turned the adjustment screw about a 3/4 to a full turn and it did help some. It would raise the RPM at which it shifted just not the force of the shift. The car('79 Ranchero) was my fathers and we installed a 460/c6 from a '76 T-bird all stock and it was a runner for being stock, I installed a B&M shift kit and even with a 2.50 geared rear axle it would bark the tires when it shifted to second. Now after building a 9.5-1 460 and installing a rebuilt C6 w/ TCI SNS torque con. along with a 3.25 posi rear diff it just doesn't shift as hard as it should. Gregaust, you mentioned a pressure gauge, where should I plumb the pressure gauge? When we rebuilt this trans we checked all the clearances to factory spec. (had an actual 1976 Ford chassis shop manual, lots of great info in them). The fellow who built the trans pressure checked a few things with air to make sure it was sealed and everything moved as it should. I am going to open up the trans and remove valve body to see if I made a mistake of some sort, while in there I'll check the servo lever ident. letter but every piece of information I can find seems to signify that the "P" servo has an "A" lever, I don't think this combo was changed at time of rebuild. Sorry for the long post just trying to give additional info. Thanks again guys for your help. Todd

Todd there is a pressue test port on the left side just forward of the shift linkage. I use a 350 psi max gauge. It is a good check . If the pressure is right you know you are pretty good to go.
What stall speed is that converter? . Higher stalls will cushion the shifts somewhat but they should still be a nice crisp shift. The P servo is one of the larger apply areas for the stock type pistons . It should be fine for your application. You could try the modulator screw in a little more . I weigh each modulator i fit and sometimes they can go in 3-4 turns

The TCI T.C. has a stall speed of about 2000-2200 according to TCI. I measured the pin and adjusted the modulator screw to tighten it and it did help. I took out a TCI scat shift kit and installed the B&M transpak with no noticeable difference in shifts but one thing I noticed was that both kits omit the separator plate gasket, could this be the cause of my problems? I found some info on Network54.com and states that the longest pin for a C6 would be about 1.677", I'll double check mine against this measurement to see if there is room for improvement. Thanks again for your help, Gregaust. Todd