Hi everyone!
I have a 2011 Charger R/T that has been modified. It currently stands at 550WHP. Around May of this year, the transmission went out, not unexpected but I would have thought I would have gotten a warning, but it did not. It shifted fine, didn't slip, or give any indication of a problem. Upon the recommendation of the shop that has done all the engine work, I took it to a rebuilder who specializes in performance transmissions. It took a long time to be finished for various reasons and today was the day! I picked it up and was very excited to have her back. They made no mention of a "break in" period needed, and they had road tested the car several times.
I never have done a burn out or manually shifted the car, but I do like to punch it when I'm cruising at around 70mph or so, or if some unlucky SOB wants to test me when I am on the road. So, of course I did that. It went well as always but it seemed to have a very hard upshift to it when I put the peddle down. It also seems to be a hard 2-3 shift when I am driving around the city. I realize I have to call the transmission shop about any thing I am unsure of but, I would appreciate anyone's opinion and comments

Thanks!

 

Probably normal. Generally, a 'performance' trans will have harsher shifts than stock.

 

You don't want slow, mushy shifts behind a performance engine. Probably the reason your first one broke, unless you had the TCM performance tuned or installed an SRT TCM.