Mazda 626 2001 GF Automatic

Sounds like you are due for either a new mechanic or a new husband.

How many miles on it? Anybody ever done any transmission work on this car?

Car Jumps .. Error Code P0715 - Mazda 6 Forums - Mazda6Club.com

2004 Mazda 6 Transmission issue - Car Talk

P0715 - transmission speed sensor question - Mazdas247

I would take a look at the transmission fluid....if it's black, you probably need a new transmission....if it looks good (clear red)and smells normal(not burnt), then maybe just the transmission speed sensor....

Mazda 626's are known for their bad transmissions. We had a Millenia with a bad tranny and after doing some research I found that late 90's- early 00's Mazda 626 and Millenia had horrible transmissions. Ours had the hold/overdrive problem right before it let loose. The tranny would get stuck in 1st and 2nd until warm until finally it wouldn't go into any gear.

Since there's black oil in the sensor, it sounds like the transmission is gone. When you smell the oil, it will have a putrid odor and is actually dark brown, not black.

Go to: www.carcomplaints.com/Mazda/626/2001/transmission/power_train-automatic_transmission.shtml 126 transmission complaints!

The 626 has a transverse engine ( crosswise mounting ). This mounting requires at least one electric fan for cooling the radiator. These fans can be very loud and make it sound as if the engine is running fast. I would expect a tachometer in this vehicle, but if you do not have one it would be simple to open the hood and hear that the noise is coming from the fan not the engine. It is typical for the temperature controlled fans to kick in once the engine warms up, then you hear them roar, especially on warm days and sitting at stop lights.

As to the problem with hold/overdrive and the black sensor and rough shifting, I would replace the Trans fluid and recheck after 50 km or so. If the fluid was contaminated it could cause these problems, and damage as well.

Transmissions sense engine speed and vacuum as well as electronic controls for shifting. A computer selects the shift timing. If you have rough shifting it may be wear, or dirty fluid, or computer problem or sensor problems.

My best advice is to seek out a MAZDA forum and talk to those who specialize with these vehicles, they have most likely seen this before and know what to look for and do. DO THIS sooner than later.

Good luck !!

Look for an unplugged/damaged wire would be my first move. There would probably be other codes for "too high" or "too low" (always high or always low) type situations that would indicate a bad sensor. This reports "no signal" I believe.