Automatic Gear Box Problem

Same issue happened to me recently.
A whining noise when transmission was cold, but disappearing when warmed up. It sounded more like the belt pulley bearing
Suddenly the car stopped moving in any gear. After reading this thread, I gave it a try with the filter. It was completely blocked!
Don't know how this could happen while the car has only 85K Km and having Stock tires , used normally on road, except some weekend dunes driving.
Although service manual recommends Transmission fluid to be changed at 160K in normal driving, I was aiming to change it at 100K.

I cleaned the blocked filter to give it a try, and replaced 2L of the ATF. Surprisingly it moved again, so it was the blocked filter which was responsible for the pump giving this noise when the fluid was still cold.
1. Is it normal that the filter gets completely blocked that early?
2. Although the transmission works normally now, but a new hectic gear change appeared when shifting from 2nd to 3rd only. What can that be, and how to solve? I'm intending to get a new filter and change the ATF after being sure it was the filter, can that solve the hard shift problem, or can there be some clogging in one of the solenoids or valves?

160K kms or 100K miles sounds like A LOT of miles to put on automatic transmission fluid without a change.
I generally change my ATF and filter every 2 years or 30K miles; whichever comes first.
I look at this as cheap insurance since the ATF is the life blood of the transmission.

Learnt the lesson the hard way
After another 1000Km 4th gear started slipping. I brought it to the Auto Trans mechanic and he disassembled it and found the 1st and 4th clutch packs burned out.
All clutch packs have been changed now.
He advised to change ATF every 40K Kms in the future according to my usage.
I also added an auxiliary Transmission fluid cooler to prevent the box from overheating, since high temperatures shortens the useful life of ATF dramatically.