Automatic Transmission Failure causes high fuel consumption?

[CMF_bopol]

Hi all!
im new to the forum and just recently inherited a micra from my sister which means there is little to no maintenance of the car! =( im not well versed with cars yet as im still learning the parts!lol
since i joined this forum, i got so many useful info from previous posts...thanks so much for those! especially on how to save fuel and what to look for when the consumption gets high, low-cost performance tweaks, proper car maintenance, and many more...

anyway, i recently had my micra checked because of the high mileage (now @ 8km/liter, then @ 11-12km/L with Aircon, city-driving) and the mechanic told me that the problem was with my "clutch" in the auto transmission... is this possible?does a faulty or damaged automatic transmission cause higher fuel consumption?
i just had all the filters changed, new oil, new transmission fluid, new wheels (165/65 r13 @ 32 psi) and fixed oil leak. engine is still not tuned-up though and i havent replaced o2 sensor since i cant find the sensors here in the philippines and im not really sure if the sensor is already broken or not...
the mechanic told me he was pretty sure it was the auto trans because when my micra is put in Reverse gear, it has a strong "kick"...

any ideas or suggestions where else to look?

yours truly,

newbie in limbo

 

[CMF_Doom]

How many kilometers has the car done?
The auto box's generally let go at about 150,000kms. If the car has had little maintenance, then chances are its on its way out :-(

 

[CMF_david (2)]

check the carbon brushes. You can search on here to find out how.

 

[CMF_bopol]

its still @ 70,000kms with little to NO maintenance...and its surplus from japan so idk if the tacho was reset...probably was... il try to check the carbon brushes and do the throttle body resoldering

thanks so much for the info! =D