904 flare up issues

Have you tried adjusting the throttle pressure linkage? Set it so that at WOT the linkage is pushed all the way back and try it. If it hangs in gears too long back it off a little at a time until it shifts when you want but doesn't flare up.

The only trick I would do to make it shift better is to remove the accumulator spring and install a blocker rod in it's place. Turning up the line pressure on an old trans. is not advisable. That may cause blown seals. If you want it to work great spring for a Trans-go TF2 kit.

If you want to know how a Torqueflite works buy this book

[ame="http://www.amazon.com/s/ref=nb_sb_ss_i_0_8?url=search-alias%3Daps&field-keywords=torqueflite&sprefix=torquefl"]Amazon.com: torqueflite[/ame]

Tons of great information and pictures in it along with a complete explanation of how the torqueflite works. 904's and 727's work the same.