What gears do I have ?

[huitt06]

Bought an 99 a4 TA over the weekend. Kid I bought from said it has kook headers, ls6 intake, and gears. He doesn't know gear size because bought already installed. Anyway to figure it out?

[Firebirdjones]

Hard to guess. It's been popular over the years to shove the 6-speed rears in the auto cars for the 3.42's they had, or someone could have shoved 3.73's in there.

Since it's a new vehicle it would be a good excuse to do a rearend oil change and check for yourself that's what I'd do.

[huitt06]

Hmmm. ...guess I will have to

[35th-ANV-SS]

You can count how many times the driveshaft turns with one revolution of the rear wheel. If it turns about 3.5x, you have a 3.42 gear. If it turns 4x, you have a 4.10/4.11 gear, if it turns 4.5x, you have a 4.56 gear. You get the idea. Marking the driveshaft with a visible paint stick/line makes it easier to count the turns. You'd do this with the rear end jacked up (securely).

Or, you can take the pumpkin cover off as stated above.

[35th-ANV-SS]

You can also use an online calculator based on your speed/rpm and factoring in your transmission ratio and tire size/height.

[huitt06]

Will try that first ^

[35th-ANV-SS]

As FBJ stated, it is still a good idea to change your gear oil and take a look at things.