I use 2002 Nissan Altima 2.5S with automatic transmission ;recently the transmission Gear started malfunctioning; the the forward shift and the reverse shift works normally but when put on Drive D, it does not select or shift to engage and move normally. When you accelerate, the engine rev very well but the car would not change speed. The speedometer would remain on 20kM per hour.
I decided to buy another fairly used transmission gear ( probably 2005 Nissan Altima transmission Gear ) After the installation, the problem remains, the transmission gear does not select on drive D; in addition, the speedometer does not work again.
Please can somebody suggest to me the solution to this problem?

Richardson Adesuyi

I'm confused, did you buy the gearshift assembly or the actual transmission?

What Iam saying is that; I observed that my 2002 Nissan Altima 2.5S was manifesting serious malfunctioning to the extent that it became very very slaugish in movement. No matter how had you press the accelerator, the speedometer would not go beyond 20km/hr. with the spark plugs becoming wet continuously.
In my Country, we do not have access to good and professional automechanics with modern tools, therefore I decided to buy a complete Nissan Altima QR25 Engine with the Gear attatched.
QR25 Engine - The following particulars were engraved on the body of the Engine:
QR 25
124772A
LPTWB; AKC
OTHW
HA9
The Transaxcle Transmission Assembly has the following characters imprinted on its body : 85X71
After the installation of the Engine and transmission assembly, the engine work beautifully; the car sound very much like a new engine, very quiet. the car could reverse without any difficulty, when put on Drive D, it would move forward but at 1500rpm - 2000rpm, it is expected that the transmission should shift so that the speedometer can increase and also the speed of the car.
Rather than picking up speed, the speedometer of the new transmission remains at zero and the vehicle would not increase in forward movement even when the engine rpm is around 3000.
I suspected that the fairly used engine is Nissan Altima 2005 because the Exhaust Manifold with the Catalytic Converter only has one OS Sensor, the Green Colour Terminal OS Sensor.
My Automechanic installed original Catalytic converter because of the two OS Sensors. The Mechanic did a very fine job because the engine runs very smoothly.
Iam contemplating of inviting programmers to come and programme the ECM and TCM to put the computer in learning mode so that it can synchronize the operations of the transmission assembly.
Please use your experience and expertise to advise me on what to do. I love the car and I have been giving it the best maintenance available.
Thanks,
Richardson