Check the motor mounts. If rough when going from Park to reverse or even when in drive it's possible broken mount is the reason. Had same issue and replaced mounts and no more problems
electronic solenoid
have you ever had the transmission filter changed and fluid changed?? Great place to start looking. If you have already checked the fluid level!
modulator valve on the transmission.
Possibly low fluid.
A bad transmission gear can cause your 1999 Nissan frontier to shift hard. Low transmission fluid can also cause the transmission to shift hard.
maybe someone put a shift kit in the tranny.
There are several causes that an automatic transmission will not want to shift into second gear. The two most common causes are transmission pump issues and trouble with the vacuum modulator.
On a 1999 Cadillac Seville SLS, the shift solenoids are located within the transmission, specifically in the valve body assembly. To access them, you typically need to remove the transmission pan and the valve body itself. The solenoids control the shifting of gears and are crucial for the proper functioning of the automatic transmission. Always refer to a service manual for detailed instructions and safety precautions when working on the transmission.
a bad radiator -automatic portion of radiator not cooling off transmission
A seized up transmission can cause a Volkswagen Golf with an automatic transmission to not shift and racing RMPs after second. A worn gear can also prevent shifting.
balls. balls will slow shafting
what can cause your car not to shift gears besides the transmission