Got a 99 3500 w/102000 mi and just started having the torque converter lockup going in and out @ 42 - 48 mph. Doesn't help to back off or give it fuel, just cycles in and out every couple seconds till it gets up toward 50. Holds fine after that. The only thing that I've changed recently was going from 215 tires to 235's. (Looks a heckuva lot better without the "skateboard" wheel look). Haven't gotten the speedo recalibrated, could it be the ABS sensors arguing with the speedometer? Any ideas?

 

You can try re-calibratng the apps to help your problem. But you should have the dealer flash the PCM with 18-02-99 tsb.<br><br>To recalibrate <br><br><br>1) unhook batts for 5-30 min'<br>2) hook up batts<br>3) try key to run, not but do not start<br>4) push the go pedal slowly to the floor and back three time<br>5) turn key off. <br>6) drive truck <br><br><br>JR passed posted this before and it worked for me on a 99 auto. The problem came back until I had the PCM flashed.<br><br>Malcolm

 

&quot;preciate the quick response Malcom, I'll give it a whirl in the morning...Thanx