C4 Transmission issue

[jmantle]

Originally Posted by HawkBrosMav

We’ve got a pretty good rpm flash during the 2-3 shift. I’ll have to look at the logs, but shift around 5900 on the tach and you can see the tach flash up to about 6400. The 1-2 if there is a flash is much less noticeable on the tach itself.

This has been something we’ve noticed much more since we took the stock 1st gear out and put in a 2.92 ratio. I personally don’t know why that would give us a flash unless when reassembling we got something adjusted incorrectly. Just swapped to a brand new ATI converter and a different cam recently and the car is as fast as it has ever been but the flash seems to be worse.. any suggestions on making it go away and/or if we are losing ET because of it?

You didn't mention what you had the front band set at. Stock setting with a course thread adjusting screw is 1 1/2 turns, 3 turns with a fine thread (C5) setup. Setting the band tighter than stock will reduce a 2-3 flare but I wouldn't go tighter than 1 turn on the course thread or 2 turns with the fine thread setup. A good test after setting the band tighter than stock is make sure the driveshaft will turn by hand in both directions after you set the band.
As mentioned by others, you may have direct clutch issues that a band adjustment won't fix.

Jim Mantle V/SA 6632