Hello! I have a 2014 Lexus ES350 with 78k. Tranny slips between 3rd and 4th, but only if under 2200RPM.
You mentioned not long ago that Lucas Oil Stop Slip is only good for domestic cars. Why is that?
The older domestic cars use thicker oil for transmission and so they are not as sensitive as modern cars. The modern transmissions are very delicate and you need to be very careful what you add. Your car does not have too many miles. Have you serviced it before? If not, change the fluid and filter.