automatic gearbox problem

[kenivruh]

Hi all. In my Z32 twin turbo automatic gear box stopped to shift past 2nd gear (so only first two gears work). After changing gearbox for another one, it still doesnt shift to 3rd gear (nor 4th).

Now I will add details what we have done to check what is wrong.

1. conzult diagnostics shows no errors
2. all sensors return values to conzult, so we can see that speed, rpm, tps, OD is available
3. during test drive we can see in conzult that ecu tries to shift in 3rd and 4th (shift solenoids A and B are turned on and off in ecu as they should)
4. al wires to ecu and to transmision are ok, not short circuit no open circuit
5. resistance on solenoids is like in manual
6. on oscilloscope connected to wires for solenoid a and b, we can see 12V and 0V when required, we eve checked current in wires and it is also as it should be
7. when AT control unit is disconnected car stars and moves only in 2nd gear

So after all this I expect that ecu and wiring are ok and problem is in transmission (high clutch).

Could this be that also second transmission is wrong? Is this problem common on Z32 gearbox? Is there something else what can be checked?

[kenivruh]

Nothing? Can just somebody confirm that when TCU is disconnected transmission should work in limp mode and be in 3rd gear?

[nissanfreak12]

I had issues with my auto when I first got it a while back, test the TPS. This caused a ton of havoc when mine was going out. Worth a shot.

[kenivruh]

Thanks for reply. Well TPS looks OK, cause we can see it change value in conzult.

[pimpastic]

I've just read your post re your transmission problem, i recently just experienced this exact problem. have you had any luck with fixing the shifting issue? It happened to me when on the highway passing. It kicked down from 4th to 2nd perfect, but then like a light switch turn off, the transmission would not up shift. It stayed in second, but will opperate 1st and 2nd after comming to a stop.Reverse works fine as well.Replaced solenoids and tested a couple of key circuits. Im thinking new transmission.

[kenivruh]

I've put in another transmission. In my opinion high clutch which is used in 3rd and 4th is gone and needs repair.

[Ace2cool]

Yeah, autos are one thing are I'm bad at. Which is odd because both of my Z's have been auto. I just can't understand them past basic mechanical aspects, i.e. torque converter, lines, ect. Wish I could provide a bit of insight, but I'm no good with them.