My 96 Legacy GT Wagon's Speedometer is reading fast by 15%-20% That means when it says about 36, I'm only going 30-31, and when it says 70, well I'm only going about 55. It has what is supposed to be the correct 4EAT transmission. The speedometer is original, the tires are the correct size for the car and have about ½ their tread on them. What could be causing it to read soo far off, and does anyone know how to fix it?

 

Keith

i guess if you're sure the final drive ratio is correct it's a waste to check, but i'd want to verify what it has versus what it should have. rotate wheels and count driveshaft rotation, it's not too hard...annoying part is just looking under the car. 10 rotations of one will give 3.9 or 4.11 turns of the other..or should?

 

other than being off by that amount it doesn't do anything erratic, jumpy, sticking, etc? bizarre.

i guess if you're sure the final drive ratio is correct it's a waste to check, but i'd want to verify what it has versus what it should have. rotate wheels and count driveshaft rotation, it's not too hard...annoying part is just looking under the car. 10 rotations of one will give 3.9 or 4.11 turns of the other..or should?

 

other than being off by that amount it doesn't do anything erratic, jumpy, sticking, etc? bizarre.

 

No, it doesn't do anything crazy. The drive ratio better be the same. I bought the car with a bad transmission, and the replacement unit was bought based on the car VIN, and the numbers matched between what came out and what went in.

i guess if you're sure the final drive ratio is correct it's a waste to check, but i'd want to verify what it has versus what it should have. rotate wheels and count driveshaft rotation, it's not too hard...annoying part is just looking under the car. 10 rotations of one will give 3.9 or 4.11 turns of the other..or should?

 

other than being off by that amount it doesn't do anything erratic, jumpy, sticking, etc? bizarre.

 

Mine is off by about 10% as well, I'll have to check that the final ratio is the proper one for my car.

How did you determine that the speedo is off?

The Speedo is off by about 10% by nature of of the speedo setup. I don't know how to account for the other 5-10%.

The Speedo is off by about 10% by nature of of the speedo setup. I don't know how to account for the other 5-10%.

 

How do you figure that?

How do you figure that?

I just know that on the 1990-1994 Legacies, the speedo is off by about 10% on standard size wheels and tires. I don't know why that is, but it just is. I figure it's something to do with the speedo setup and gear in the 4EAT.