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1995 Nissan Quest Question: What exactly is "Bump Shifting?"

 

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Temre, 3.0L V6, Santa Ana, CA, May 23, 2010, 11:13
 Rookie

Is continual erratic hard shifting from 3rd to overdrive while on fwy considered "bump Shifting?" I have a 95
Quest that up-shift every time I accelerate and downshift every time I let off the accelerator. Or what could it be?

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  • Answer #1

    May 23, 2010, 18:02
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     Master

    This is often caused by too much clutch pack clearance in the Transmission or very dirty fluid. When was the last time you serviced the transmission?

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    Visitor, December 20, 2010, 10:04

    Continuing on from below - leaning toward TPS (maybe WOT switch is making too soon). Code 8 also points to Fluid Temp sensor (which is part of solenoid harness) - is removal of control valve required to change out solenoid harness?

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  • Answer #2

    Visitor, November 20, 2010, 20:16

    I have the exact problem with my Nissan Quest (94) you will want to check for various problems here. Check all your hoses on the engine and transmission also check your wiring harness and your transmission fluid.

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    Visitor, December 20, 2010, 10:01

    Here's my problem.... Originally I would shift from 1st to 2nd at 3000 RPM. I would not go into overdrive on the freeway, even on a downhill (or it would be delayed). Sometimes I wouldn't go into 3rd at 35 MPH. Also, when starting on a steep grade, it would rev to 3500 RPM; I would have to back off the throttle to get it to shift and then it was very sluggish (it would also downshift with the slightest throttle pressure).
    The other issue I had was that it would sometimes downshift from overdrive to 3rd on the freeway for no apparent reason or if I accidentally hit the pedal hard it would rev to 5000 RPM (if I was not in overdrive; acted like it was downshifting to 1st gear).

    Now, the only problem I have is that moderate throttle (less than halfway) causes a downshift. Everything works fine as long as I maintain a somewhat light throttle.

    What helped was doing a transmission fluid flush, changing plug wires and finding the vacuum hose from the evap canister was not all the way on the fitting.

    If I run the self-diagnostic (using the OD OFF light), I get a Code 8 (Fluid Temp) but only right after shutting off the engine (and usually after driving for some time). When the shift lever is in "1" during the test, the OD OFF light will go out when the pedal is close to the floor (suggesting the Wide Open switch on the TPS might be working properly; could be a false indication).

    No "check engine" light. Speedometer is OK.

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