I've been working on my 06 mega cab lately after not driving it much the last couple of years. Before I had quit driving it, I was having a vibration issue that would arise immediately after the transmission shifted into overdrive(at least that was when it was most noticable). It would lessen as the speed increased and the drivetrain load was lessened. I figured it was probably transmission related as I had over 600,000 miles on the original transmission. I had the transmission rebuilt with Suncoast billet flexplate, triple disc billet converter, billet input shaft, billet band, new intermediate and output shafts, etc etc. Although the trans works great, this did not fix the vibration issue. I also had the front ball joints replaced and all tie rods/ends etc around the same time. I still have less than 5000 miles on the transmission and less than 10,000 on the front end work. I have just replaced all shocks and had a custom one piece aluminum driveshaft built. I still cannot get rid of the shudder when it shifts. It doesn't do it nearly as bad when I accelerate through the gears using fairly heavy throttle to get to highway speed. It's the worst when I use light throttle and then give it more throttle right after the shift(worse in od). It clears up for the most part once it's to speed but seems to still be there a little bit. It feels like a tire out of round when it happens.
About the only thing left I can think of is possibly injectors, harmonic dampener, motor/ trans mounts or track bar(can't remember if the track bar was replaced when the front end was rebuilt). I don't have any codes showing and the motor and trans mounts look ok although they are original. Can't see any visible issues with the track bar either. If it was injectors or dampener, wouldn't it vibrate all the time instead of just when it shifts?
If anyone has any ideas, I'm all ears. I'm about at my wits end. I tried the search feature but most of what was found had been addressed.

Thanks
Dave

 

How many miles on your injectors?