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Duramaxpax
June 18th, 2014, 11:55 PM
Not sure if this is the right place for me to be post iff this but I'll give it a shot in hopes somebody can help because I'm getting frustrated. Truck is a 2007 silverado 1500 classic 4wd ccsb. 5.3 in it on 12" lift with 37s I had 5:13 gears installed today in rear axel and my shift points were way off in my trans I did not install gear in the front differential because I never use 4wd so I didn't think it would matter. I met up with the guy who does my EFI Live tuning to adjust my gears size and now my truck is still shifting way off. If I lay into it from a dead stop it acts like it wants to shift but it contines to whine and my rpm continues to go up and then will eventually shift. My question is, do I absolutely have to install the 5:13 gears in the front differential to solve the issue? My shifting is way off trough all my gears and my tuner is qualified but even he is stumped. He adjusted my shift points and everything but it's still not shifting correctly. So I'm hoping someone on here can help me figure out what's going on. Once I'm in 4th gear and if I put the peddle to the floor, my rpm continues to climb and won't back down. My speedometer bottoms out at 75 mph and 6000 rpm. I get this horrible vibration which feels like it's coming from the rear driveshaft or the front tires. I did not have this shaking before the regear. Thanks.

joecar
June 19th, 2014, 04:27 AM
Look at the PT upshift/downshift tables, and make sure that none of the curves cross each other, and that each end point on each curve is a sensible rpm (for the mph for that curve's gear).

Make sure WOT upshift/downshift MPH parameters match the PT upshift/downshift endpoint (100%) MPH values;
make sure WOT upshift RPM values have been dropped down significantly (to let the WOT MPH trigger the shift).

Also make sure Throttle Kickdown tables are all 100%.