QX4 transmission problem

[spford]

My 98 QX4 just started downshifting from OD to D every time you turn the headlights on. Runs fine withe the headlights off. About a month ago I replaced the two wires from the positive battery terminal to the fuse/relay box. The vehicle has a new battery.

[Towncivilian]

Okay, that's a weird one. Please check your transmission fluid level:

1. Drive around for 10 minutes in the city after the transmission is at operating temperature.
2. Park on a level surface and apply the parking brake.
3. With P selected, shift through every gear and return to P.
4. Pull the transmission dipstick with the engine idling, wipe it clean, reinsert it completely, and read the level. It must be within the notched area labeled "HOT". Check for fluid contamination after wiping on a paper towel.



The fluid should be red, and not smell burnt.

Has the fluid ever been serviced? Is your "SERVICE ENGINE SOON" light lit, or does the "O/D OFF" light blink 7 times or so when you start the vehicle?

Welcome to NICO. I've moved this topic to the Pathfinder / QX4 section.

[spford]

No flashing OD light and fluid level and color seems fine. Not serviced since we purchased it 2 years ago.

[Towncivilian]

Try a drain & fill of the transmission fluid. The approximate drain and fill capacity is 4 quarts. Use Nissan Matic D fluid, preferably. Use a new copper crush washer (part number 11026-01M02) for the transmission drain plug. The torque spec for the drain plug is 25 ft/lbs.

Is there any corrosion on either end of the battery terminals?

[spford]

Shop now telling me the alternator is failing when you add load. Disconnected alternator and it runs fine.

[Towncivilian]

With a failing alternator, I would have expected the battery, brake, and "A/T OIL TEMP" (if equipped) indicators to be constantly illuminated, but I suppose it makes sense that your alternator could be causing such issues.

I would still suggest a drain & fill of the transmission fluid as preventative maintenance.

[spford]

Thanks for your help. I will report back after the alternator is replaced.

[CanuckQx4]

You didnt report back! I need to replace my alternator I think. Battery and Brake light are illuminated and the car is only running @ 12.4 volts while running

Transmission is also not wanting to shift into 3rd or 4th.

My alternator is extremely dirty from having the oil cooler leak long ago, I guess Im just going to order one and stop driving the truck til it arrives