I have a C-6 behind a 6.9 diesel. It has an early upshift, no passing gear although it will downshift sometimes at part throttle if the load is just right, 2-3 shift flare and sometimes it takes off in second. When its in gear it's solid. This trans started out life in front of 3:55's in another truck. Now it's in front of 4:10's. Shift flare was not evident in the other truck. Other symptoms were but at a lesser degree. Seems worse hot. I have:
Installed a shift kit, When installing shift kit I found no intermediate servo spring in transmission pieces or otherwise. I installed the spring provided in the kit and adjusted the band, disassembled the valve body, cleaned and polished all the spool valves. Reassembled carefully paying extreme attention to dirt and torque specs. Have adjusted VRV and vacuum modulator all over the place and have slightly improved shift pile up but no affect on passing gear or 2-3 slip. It still starts off in second intermittently. Modulator holds vacuum and pin is present as is vacuum. My altitude is 6200 > feet and 15 inches of vacuum is all the pump will produce. I have not run pressure tests I have no gauges, Has MerconV in it. I need help from a Ford trans tech. I am a Ford tech but my specialty is not transmissions. Whats up with the missing servo spring? Servo concern? Governor problem? High reverse clutch? Reverse is solid. Thanks for reading my book..... HELP! <!-- / message --><!-- BEGIN TEMPLATE: ad_showthread_firstpost_sig --><!-- END TEMPLATE: ad_showthread_firstpost_sig -->

 

Sounds like a linkage concern, or a poor seal between the VB and plate.
Reverse is isn't a problem because it applies full direct line pressure where the governor cuts down the pressure for the drive gears. A leakage at the selector valve will cause these problems. A weak pump is a distant possibility.

 

I will recheck the linkage sounds like a good idea maybe I've been thinking Zebras when I should have been thinking horses. What do you think about the servo spring? When the trans was in the other truck it didn't have the 2-3 shift flare it also had no servo spring. Is it possible that someone removed it in order to affect the 2-3 shift flare? I have been reading alot about the r code servo and it's ability to take care of this concern so it got me to thinking..... maybe it was a poor mans mod? I know enough to be dangerous and I don't really understand clearly how the servo affects the 2-3 shift flare concern since the band is not applied in third gear.