95 J30 high rpm shift 1-2

[norbus]

Hi:

I've had my transmission rebuilt (yes I know I should have went with factory reman but too late) and I have this remaining symptom where sometimes it won't shift from first to second until a really high RPM with real light throttle. Then it will kind of stumble down all the way to third when it shifts then shift right back up to second giving a weird almost slip feel.

The transmission shop says the transmission mechanical parts are functioning fine, but the solenoid isn't being activated at the right time.

A lot of the time it works fine. I put an entire new solenoid kit in with the rebuild.

transmission shop suspected TPS and I replaced that but still seems to have a problem.

What can cause it to mess up this shift point? Does it both hot and cold.

Norbus

[Q45tech]

You use the Consult diagnostic computer to monitor all the shift functions including the solenoid signals and the engine ecu/tcu parameters. Have a dealer look for fault codes!Should be fairly easy since the transmission is common to the Pathfinder and 300zx non turbo so any Nissan shop.

Not having the TPS set at 0.44 closed and 4.4volts WOT can cause problems.

[autotech43]

The transmission fluid temperature sensor can do a number of tricks on the auto transmission. Also it will not set a trouble code relating to these items you described. As stated from another user, a trip to the dealership where the technician can perform a test drive with consult connected so he can monitor what is going on in REAL TIME will usually determine the culprit if it is relating to TCU/ECU/SENSOR type problems.

[VimyJ]

transmission shop suspected TPS and I replaced that but still seems to have a problem.

What can cause it to mess up this shift point? Does it both hot and cold.

Norbus

This post has been on my mind but I haven't had the time to respond since reading it. The TPS has to be exactly adjusted or it will really screw with the transmission's performance. Spec's are .4-.5 volts. My testor isn't sensitive enough to detect that subtle a difference so I just incrementally adjusted it until it got "normal" again. Mine is still not quite right but it's almost there. The TPS can do all that you mentioned and mess with the way the TC locks and unlocks. Moving the TPS in fractions of a mm affect the way the transmission functions. Check it out before you do anything else.

[VimyJ]

This post has been on my mind but I haven't had the time to respond since reading it. The TPS has to be exactly adjusted or it will really screw with the transmission's performance. Spec's are .4-.5 volts. My testor isn't sensitive enough to detect that subtle a difference so I just incrementally adjusted it until it got "normal" again. Mine is still not quite right but it's almost there. The TPS can do all that you mentioned and mess with the way the TC locks and unlocks. Moving the TPS in fractions of a mm affect the way the transmission functions. Check it out before you do anything else.

I should have made mention that my method for adjustment involved carrying a Phillips head screwdriver in the J and adjusting the TPS every few miles of combined city/highway driving. I aimed at recreating the feel of the first to second gear change and proper function of the TC. It was interesting to note that at one point I had what I thought was the right setting but I couldn't keep the TC from switching off rapidly especially upon decelleration. However, when I switched the cruise on the TC behaved normally. This must be related to Q45tech's post about throttle effiency vis a vis manual vs CC fuel effiency. The OEM specification of .4-.5 volts is crucial. At this point in my adjusting, the last tinkering with the TPS mounting screws amounted to tapping once on the frontmost part of the switch once with the butt end of the screwdriver. Even this tiniest of adjustments resulted in a different response from the transmission. Wish I had never f##ked with this thing in the first place!:mad: