Hi, I have Hyundai Accent 1.4 and 2006 model in UAE Automatic. I am facing problem according to gear.

(Original Gear) : The Original(Company fitted) gear was not changing to 2nd and 3rd..... when I press the accelerator the RPM goes Up and Up and in the beginning RPM get very high to move the car after that the RPM and the speed goes Up and gear does not changes. Car speeds up only in 1 gear.

I got to mechanic and he told me to change the gear so I bought another Gear(2nd hand) from market and changed the gear.

(Second Gear) : After changing the original gear the newly installed gear has the same problem as the original one. Mechanic told me to check the car with Computer. I went to another mechanic to check my car with Computer. There was no problems shown in computer neither the check engine light was on.

I got to another mechanic he told me that the gear I bought has problems he told me that he will buy gear by himself and install it.

(3rd Gear) : Afterwards the mechanic bought another Gear(2nd hand) and installed it. After testing the third gear also has the same problem as the other 2 gears.

I dont know what to do. If one gear has problem so the other gear should not have exactly the same problem.

Anyone know what is the problem. It is a problem with Engine or the Gear or anything else?

 

It's certainly not an engine problem.
I agree with you that it is unlikely that all 3 automatic transmissions have the same problem. I think that this proves that even your original transmission was probably fine.

I am guessing that there is a problem with data that the computer uses to decide when to shift up or down. The most important sensor for that is the vehicle speed sensor.

Hopefully your mechanic can borrow one and put it in just to see if it works.

 

Thankyou for the suggestion but I bought new sensor and still it is same.

if the sensor will not work properly than there should be some error after checking by computer but there isn't any.

the first time when I changed gear than after connecting computer there was one error " 4 gear ratio not correct" something like that so the mechanic cleared that error but the problem is same.

 

I am sorry. Transmissions are not my strong suite. There is one thing your mechanic could test: are the shift solenoids working properly?

Make sure the ground connection between the transmission /engine and the body is good. Disconnect and clean the contact surfaces at the grounding strap(s).

By the way it is not totally unlikely that the same condition exists in transmissions of the same series. They are built the same way with the same materials and the weakest part fails first. Still, I would not expect that and I feel the problem is outside of the transmission itself.

 

Sometimes we overlook some things and I am guilty of that too.
Something that might have been overlooked and that is, there is a provision for the computer to receive the correct info in order to select the correct gear based on engine RPM and vehicle speed, but is the computer getting the correct message as to whether the info from the gear selector switch position may not be telling it the correct position.
If the computer thinks you only want to stay in second gear (position switch) it will hold it in second. Might be a good idea to have that part checked out.