have CAMARO with 185K on tranny -it chatters at 40mph & 50mph fluid has about 35k on it.Engine runs great tranny shifts great EXCEPT at 40 & 5o mph.
See your owner’s manual.
Most common seems to be around 50k-60k miles.
Some newer cars have “lifetime fluid”. Ignore that and change it!
mine says 100 k
On Us cars, 50,000 miles is typically recommended. If you pull a trailer or burn rubber consistently I would make that 25,000 miles.
I think that would be the lock up torque converter locking up. Some are worse than others. Don’t know if an additive would help or not to smooth it out. Replacing the converter would not be the end of the world but not cheap but if it blows, it spread junk through the trans and then a rebuild is required.
Transman will know better but haven’t seen him here for a while.
I do my 89 Accord (manual) every 25k and my wifes’ 95 Civic (automatic) every 25k. Works pretty well for me, both cars have served us well. The Accord has 450k and the Civic has 165k, no tranny problems EVER. Rocketman