Toyota Corolla Se Saloon 2003 A/T Problem

Dear brothers, Salam to everyone. I would ask you all a problem that relates to my sisters (family) car, which is a 2003 model Toyota Corolla SE Saloon that an automatic transmission. It drove beautifully and has covered 100,000 km (Mashallah). Recently, after being taken care of properly and timely maintenance and all that it has a weird problem. The car's transmission shifts gears now, but with the acceleration and speed drop that is quite normal, something that shocks the car feels kind of awkward. The jerk I'm trying to explain was not present before and since the last two oil changes (transmission oil) has seemed to appear. While we have always put real ATF Type IV fluid, as proposed gear this issue remains unresolved. We have gone to Toyota workshops only here that this is a common problem and a problem in this model (model error, all the cars to develop at some time or another in this category and trim). So we went to many mechanics, but still got the same response from a jerk is normal and an indication of optimal and appropriate gear. (I'm not even a jerk shift is normal). I mean we have this car for over 7 years and never have I or my sister seen / felt this issue. Even her chauffeur says a jerk weird. The worst part is that my brother also A / T 3.0L drive-Prado RZ 1998 (Diesel) and A / T Toyota Corolla Altis 2005 (sold this car earlier this year), but says he has never seen / felt this problem in these cars and it worked out in this car (Sedan SE) overtime. If the driver drives the car we usually want this problem resolved as quickly as possible as it caused my sister and her husband (my brother) a problem like this is their family car and should be used every day and it is a huge problem. I wish my PakWheel siblings (anyone) can help resolve this issue asap.

Car is completely unchanged at intervals so timely assistance is required to solve this problem ASAP. I urge all owners and Ex Corolla Corolla owners here to help me. No non-original parts installed in the vehicle.

The problem in a summary:

Switching from first to second - Normal RPM drop - Abnormal Light Jerk that can be felt when the gear is not smooth. @ 2 to 2.5 K RPM

(Said RPM because this is where the problem is felt at max)

Same problem for the 2nd to 3rd gear, but is less jerk.

Somehow the 4th (Final Gear) does not have an issue like this and that the transition is smooth. But as R / D (Overdrive off) this gear does not engage all the gears so choppy. We have inspected the transmission and any mechanic workshop and Toyota said everything is ok.

! Only a few happy times when the car is driven under 2K RPM (1000 to 1500rpm) the acceleration is smooth, but that is not possible to stop and go traffic (normal use)!