I have a 2006 Nissan Maxima which jerks violently when the gear is about to engage (in the lower gears mainly. The diagnostics came up with a reading that talks about the torque converter. My question to the house is this.

Can you repair or change this particular item without changing the whole transmission? And if i have to change the whole transmission, what kind of figure will i be looking at?

Auto Gurus to kindly respond

Feedbacks? Please

I'm no auto guru, but I also own a 2006 Maxima. I've done quite a lot of research on the car and for your problem this is what I came up with:

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP) PFP:31940
Description ECS00A40

This malfunction will not be detected while the A/T CHECK indicator lamp is indicating another self-diagnosis
malfunction.

This malfunction is detected when the torque converter clutch does not lock up as instructed by the TCM.
This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such
as control valve sticking, improper solenoid valve operation, malfunctioning oil pump or torque converter
clutch, etc.
On Board Diagnosis Logic ECS00A41

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “A/T TCC S/V FNCTN” with CONSULT-II or P0744 without CONSULT-II is
detected when A/T cannot perform lock-up even if electrical circuit is good.
Possible Cause ECS00A42

Shift solenoid valve D
(Off stick.)

Pressure control solenoid valve C
(Off stick.)

Torque converter clutch

Hydraulic control circuit

I guess the auto gurus should be able to decipher the problem and offer solutions. A good auto workshop should also see through it.
Good luck.

Here is another description of the problem:

P0744 Description
This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by TCM as follows:

Torque converter slip ratio = A x C/B A: Output shaft revolution signal from revolution sensor B: Engine speed signal from ECM C: Gear ratio determined as gear position which TCM supposes

If the actual gear position is much lower than the position (4th) supposed by TCM, the slip ratio will be much less than normal. In case the ratio does not reach the specified value, TCM judges this diagnosis malfunction.

This malfunction will be caused when shift solenoid valve B is stuck closed.

Gear positions supposed by TCM are as follows. In case of gear position with no malfunctions: 1 , 2, 3 and 4 positions In case of gear position with shift solenoid valve B stuck closed: 1, 2, 2 and 1* positions to each gear position above
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
When is the code detected?
# Diagnostic trouble code A/T TCC S/V FNCTN with CONSULT-II or P0744 without CONSULT-II is detected when A/T cannot perform lock-up even if electrical circuit is good.
Possible Causes
# Line pressure solenoid valve
# Torque converter clutch solenoid valve
# Each clutch
# Hydraulic control circuit

Note the possible causes outlined in the two descriptions.

Thank you Costee. Even though i cant understand half of what you wrote (i am technically challenged lol), i will be able to take this up with my mechanics. Regards.
@all, more responses required please.

Hey! I'm no auto guy; I didn't write all that, they all came from the internet. But I'm sure you can (as I did) identify the probable causes/solutions of the problem from the descriptions , let your mechanics take it up from there.

Bobajo:

Thank you Costee. Even though i cant understand half of what you wrote (i am technically challenged lol), i will be able to take this up with my mechanics. Regards.
@all, more responses required please.

Any updates?