rluckas

As i posted a few weeks ago, i've been having this tranny problem on my '95 auto w/ 96000kms... to make a long story short, my transmission is downshifting unnecessarily from 4th to 3rd at highway speeds ususally on inclines and declines. Otherwise, anything below 80kph it behaves normally, nice smooth clean buttery shifts.

ECU and TCU aren't throwing any codes, i sure wish either would.

Finally had the time to bring my car to the dealership for a diagnosics, and they followed up telling me that they can't make the car do what im describing, and that they suggest i flush the tranny fluid and move on. I agreed for the service, and $165 later, i got my system flushed and paid through the teeth for diagnostics.

End result, the problem is re-occuring, Nissan can't figure it out, as everything checked out okay, and even recommended me to a transmission shop for yet more diagnostics *sigh*.

THey ended up taking the car for a vigorous road test and indeed got the downshifts to occur. (thankfully someone belives me)

They say it's very difficult to pinpoint, and that i should start replacing a few things such as "Throttle Position Sensor", "Speed Sensor", "Air Temperature Sensor", "Engine Temperature Sensor"....

well, i dont know where the heck to start, and if anyone could point me in the right direction, that'd be great...

Im getting tired of driving to work for an hour on side-roads.

Cheers,
RLUCKAS

Zirafa

I know that TPS (Throttle Position Sensor) and Vehicle Speed Sensor send signals to both ECU and TCU. If I were you I'd check the TPS first since it looks like it's more prone to failure. Check this out and see if that helps http://vbxmaxima.8m.com/tps.html

rluckas

hmmmm... good page, thanks for the input, nice close-up pics if i decide to replace the sensor myself.

reading though however he says "Symptoms: The most obvious is if the TPS just up and dies. You'll get a check engine light and the 0403 trouble code. (Trouble codes will be covered at a later date). However, if the TPS is still gasping its last few breaths, you won't necessarily get the light. But you will get inexplicable, "spontaneous" drops in RPMs. It's most pronounced when you are at idle or the engine is coasting to idle after disengaging the clutch. I have yet to see someone tell of problems when the car was moving/accelerating."


It seems it's not common for issues with the TPS when the vehicle is moving... hmmm...

Maxima99SE

iTrader: (2)

I had that EXACT same problem.... Nissan diagnosed it as a Bad Transmission Solenoid, they replaced it, the gasket in the transmission fluid pan, and flushed the tranny fluid. The solenoid, according to my dealer cost them 394.17 (it was all fixed under the 5/60000 warranty) if you need the part number for the solenoid, let me know and I will give it to you. If you have it fixed and it wasn't the solenoid, please let me know!