Transmission seems to be shifting unnecessarily at higher speeds. Sometimes causes the car to buck.
How is the transmission fluid? Both the color and the level of the fluid.
That’s the first thing I’d check.
Don’t you have a CVT? It doesn’t shift. It can slip, though. Have you had the fluid changed?
If this is a conventional automatic, might be the lock-up torque converter. Ask your shop if they can disable that feature as a test.
It’s a CVT. But it does have a torque converter. However, I’m guessing it’s the CVT part.
What’s the mileage?
Has the transmission fluid been serviced yet?
If so, when?
Nissans Jatco CVT’s have less than a stellar reputation as far as quality goes . I would have them change the CVT fluid and see what happens , otherwise I would start saving your $$$$ .
Nissan CVTs… my family had a total of 3 such animals and one failed hard (last generation, same as you have in 2014 Altima) and two CVTs of prior generation were traded before they fell apart, all had fluid changed like a clockwork.
Look for next symptoms in per-failure state:
if you had to make a hard stop from 50+ MPH and your engine stalled: that’s a clear sign that CVT could not properly “downshift”, that’s a pre-failure state (this is first sign we’ve got on 2007 Altima)
if you drive on high constant speed (like 60+) and hear “whining” from the front/transmission area: it is slippage, CVT is on the way to a graweyard (that’s what we observed on 2012 Altima, it progressed fast)
if you decelerate and hear “kinks” and “flapping”, that CVT chain slipping and getting kinked inside, drive like that for a while and it will break apart (that’s what we observed on 2013 Sentra, it progressed alarmingly fast, within 2-3 days)
getting CVT fluid changed one more time helped on both Altimas, but I knew it is only a temporary “fix” and unloaded both cars
for Sentra, it had only 42K miles, so they replaced transmission under warranty, still I immediately unloaded the car as the unit Nissan installed was remanufactured unit from another failed car