After I installed my 4.10s and gave them a 500 mile breakin period, I have been seeing a couple of issues. First of all, my overdrive light comes on and blinks. The overdrive lockout works perfectly either way. No error codes show up when hooking it up to an analyzer, however turning off the car resets the O/D light. My car was off before they tested it. Under normal driving conditions the car shifts correctly. However, under heavy acceleration from a stop, my car will shift 1>>2 normally, then 2>>3, at the appropriate time, however it then kicks down to 2nd and hits the rev limiter. This is if I keep it floored the whole time. If I let up a bit between the 2-3 shift, and gradually put the pedal down it goes fine. I am wondering if the speedcal unit is throwing off the ECU. This might explain both problems. I plan on replacing the speedcal with a chip soon, but was looking for a good explanation first if anyone can offer one. Thanks.