I was on the highway doing about 90mph with my foot off the gas. When I went to push the pedal back down I could feel the tranny "teethe" try to reengage. You could feel some of the "teethe' getting skipped over while the tranny was trying to reengage the drive shaft , Did I hurt anything? I'm scared I might have broke a few "teethe." Thanks
If any gear teeth were missing you'd know it.
Do not recall ever experiencing anything like you describe the times I have taken my foot off the gas at speed then put my foot back on the pedal. But I am pretty sure I did ease my foot down. This for both my manual transmission equipped cars and my cars equipped with an automatic, including my Hellcat.
Push down too abruptly on the pedal in an automatic equipped car and you can cause the transmission to downshift. With my Hellcat I know at lower speeds the few times I did this the transmission kicked down and did so with some drama. And the rear tires broke loose. (But not at 90mph more like around 40mph.)
With a manual transmission there is a test of the clutch that involves in a high gear applying full throttle and noting any increase in RPMs without a corresponding increase in vehicle speed. If engine RPMs climb while speed doesn't that's clutch slippage.
The test is usually done at a lower speed in a lower gear -- ideally the gear with a 1:1 ratio (as is the case with my 2020 Scat Pack and its transmission's 4th gear). But if done at 90mph, it could be the clutch was slipping.
Automatics are in some ways great but in other ways kind of weird. My SOP is try to avoid subjecting the automatic to extraordinary inputs that could "tax" its ability to deal with these in a suitable manner. Not saying the transmission would blow up just its computer controlled hydraulics might encounter a weakness that could have the transmission manifest some unfamiliar and mildly disconcerting behavior.
Automatics can act up if they are low on fluid or if the fluid is past its change by date. With the Hellcat I do not believe there is a way to check the fluid from the engine compartment. To refill I believe fluid is added, the transmission being up to temperature and the engine running and after cycling the transmission from P to D maybe R and N and stopping adding fluid when it begins to run out the fill hole.
Also, the Hellcat transmission fluid is "lifetime" which can mean it can last as long as it lasts...
If the car in question is an automatic it might not be a bad idea to give the underside of the car a visual check for any signs of transmission fluid leakage. If there is a leak this of course can result in the transmission being low on fluid which is not good.