1999 Chevrolet Silverado 2500 Question: information center flashing lights

This sounds like your Instrument Cluster is malfunctioning and needs to be scanned and repaired. Then deal with the Transaxle code. Have all the Computers on your Chevy scanned including the Instrument Cluster, the Body Control Module and the Power Train Computer. Here are some shops to help you:

http://repairpal.com/directory?address=45693&car_bran...

Yep, mine was doing the same thing and I just took the cluster out, checked continuity on all the leads on the circuit board (coming from the wiring harness) and had two that had broken contact on the circuit board, right where the plug prongs are soldered in. If you try to do this yourself, you better take you sweet time taking the cluster apart and for God's sake, work on a thick blanket, so you don't scratch any part of the circuit board while moving it around or you'll have more breaks on the board to deal with. GM has the cheapest BS circuit boards known to man and I had to learn this the hard way, when I tried to fix my A/C control switch box. I set it on top of a pair of pliers and accidentally bumped it with my elbow and just that little bit of friction cause it to scratch through the cheap ass silicone and break the copper connection line, thus I had to solder in a jumper to fix it . Good Luck