Does anyone can give me a step by step advice to flush/change the tranny oil?

THX

1. Obtain proper transmission fluid and filter for your vehicle (some vehicles don't have filters). I recommend you use a full-synthetic ATF (e.g. Mobil 1 Synthetic Multi-Vehicle ATF or Amsoil Synthetic Universal ATF), provided it meets the manufacturer's specifications for your vehicle. Transmissions run cooler (because of the higher coefficient of heat), perform better, last longer, and get better gas mileage with synthetic ATF. This is cheap insurance for protecting the most complex and problematic part of your car. Do it to save money, in the long run, and protect yourself from the big unexpected transmission repair bill. Synthetic ATF offers a "margin of safety" we all need.

2. Transmission fluid should be at normal operating temperature, before draining.

3. Turn engine off and position drain pan under transmission pan and drain fluid by loosening pan bolts. Loosen one corner more than others to direct flow into drain pan.

4. Remove all transmission pan bolts and lower pan carefully.

5. Remove old filter. Some filters are held in place by a bolt or two; however, some are held by a clip. Ensure filter O-rings or seals are removed with the filter. It may be necessary, on some vehicles, to pry out the old filter seal from the transmission housing, being careful not to nick or gouge the seal mating surface.

6. Install new filter using the same bolts or clips. Use new O-ring or seal supplied with the filter.

7. Inspect pan carefully before cleaning. Small amounts of fine gray clutch dust are normal; however, if you find metal shavings, there could be transmission damage or mechanical problems.

8. Clean transmission pan thoroughly with solvent (e.g. brake cleaner) and wipe dry, so there is no harmful residue. If there's a magnet, it should be cleaned and replaced in the same position in the pan. Clean transmission and transmission pan mating surfaces of all gasket material, being careful not to damage the surfaces. If the transmission didn't come with a drain plug, I recommend installing a B&M Transmission Drain Plug in the pan at this time. It makes subsequent changes a snap. Carefully choose a location for drilling a 1/2" hole for the plug. Some manufacturers emboss a "0" where the hole should be drilled. Install drain plug, nylon washer, nut, and torque to 20 ft.-lbs.

9. Position gasket on the pan. Some gaskets have four slightly smaller holes, to allow four bolts to hold the gasket in place.

10. Hand-tighten transmission bolts in a crisscross pattern until snug. Use a torque wrench to tighten bolts to proper torque.

11. Refill transmission through the dipstick, using the amount shown as "refill capacity" in the owner's manual.

12. If only changing transmission pan fluid, skip to Step 14.

13. To also change the fluid in the torque converter, follow the 5 steps below:

a. Obtain total transmission fluid capacity from the manufacturer and have that amount of ATF available.

b. Place a drain pan large enough to hold the total fluid capacity under the oil cooler. Disconnect old cooler line from oil cooler and direct lines toward drain pan.

c. With help of another person, be prepared to add ATF to the transmission fill hole, at the approximate rate fluid is being pumped out the transmission line into the drain pan.

d. Start engine and, as the old fluid is pumped out, pour fresh fluid in the transmission fill hole.

e. When the fluid color brightens, or the total capacity has been replaced, shut the engine off and reattach oil cooler lines. All fluid in the pan and torque converter has now been changed.

14. With vehicle on level ground, recheck the fluid level, using procedures outlined in the owner's manual. This frequently involves starting the engine and pausing several seconds in each gear, as the gear selector is run through the complete gear range (PRNDL). Check the transmission and lines for leaks. The final fluid level check is usually made after transmission reaches normal operating temperature, engine is running, and transmission is in Park.