Bearing sound do not disaapear after a while rather it increases with time and speed and the sound of the bearing is not "Khar Khar" its like an echo (goonj).
The rattling you are talking about is from the gears (grari) inside the gear box. You have not mentioned that you changed the gear oil as decided earlier.
The cause of your problem is that some of the gears which are above the normal oil level initially make such sound when the engine is being started after a few hours but after few minutes the oil is splashed over them by the moving gear below and sound is gone.
for its solution, Follow as below
- Drain out the old oil from the drain plug beneath the gear box. (the gear oil should be hot as hot oil gets out faster)
- let it drip for 30 minutes or so.
- clean the drain plug before fixing it back, use thread to seal the bolt.
- remove the speedometer cable assembly from the top back corner of the gear box (its fixed with a 10mm bolt).
- Put 2.3 litres of gear oil (Zic) alongwith 444ml of oil treatment from the opening where the speedometer cable was fixed.
- fix the speedo cable back.
The reason of putting the oil from the speedo side is that it allows you to slightly overfill the gear oil so the gears which were above the oil level should get in and remain lubricated even when the car is not used for days.
Try this before getting your gear box out of the car.