Jatco Auto Trans Strange Problem

[Alex@MKA]

Hi,

 

I have a very strange problem with my automatic gearbox type JATCO model JF506E.

At aprox 1700-1900rpm, 3rd gear, cold temperature of the ATF oil, when it should change to the 4th, is making some jerks, like the gear is trying to change the gear but is interrupting the transmision, and after 2-3 jolts is changing into the 4th.

Last year I replaces the 4th and the 5th gear. Now I changed the hydraulic block together with the electro-valves.

When the ATF oil is warm, the problem dissapears. Also, the problem is not present all the time, I can drive 2-3 days without the problem, or I could have the problem 2-3 times in the same day.

The mechanic suspects the: TCM 90%, ATF oil temperature sensor 9% and ...... 1%.

Scaning the AUTO TRANS with VAG-COM shows no error!!!

Please help!

Thank you.

[chrispb123456]

These autoboxes use information from various sensors on the engine so be sure that the engine is running correctly before blaming the gearbox.

 

Also when the engine/gearbox is cold does the car hesitate when pulling away? then goes with a jerk until warmed up.

[Alex@MKA]

Thanks for your reply.

Yes, we think that this problem could be due to a sensor, but for the moment I don't know which one, since no error with VAG-COM.

We (the mechanic and I)presume that the mechanical part is ok (99.9%).

Yesterday I did a log with VAG-COM for blocks 001, 002 ,003 and 006. Unfortunately, block 006 is losing comunication and the value for temperature measured here is -30 degrees.In the same time, the temperature measured at block 002 is increasing from - to + 70 degrees Celsius. From VAG-COM site it seems that the ATF oil is measured here, at block 002.

The point is that I don't know what is measured using block 006 !!?? so any help is appreciated.