What is the difference between the driven and the drive gear. I did one of the calculators online. It said I would need a 15 drive gear and a 40 driven gear. Helps please tired of my speedo being off.

 

The drive is a ring gear that slides onto the output shaft of the trans and is clipped in place. You need to remove your driveshaft and tail housing to get to it. The driven gear is the one that goes into the drivers side of the tail housing, and meshes with the drive gear. The driven gear drives the speedo cable (1989 and older).

 

So a dumb question would a th350 have a 15 tooth drive gear already. Or would I be better off just to get both. Also Do you know of a good website to get those from.

 

http://www.transmissioncenter.net/sp...____va.htm#350
I highly recommend using the steel speedo driven gear housing too. I had a chronic leaker with the old aluminum one until I put one of those in. Get a new drive gear clip too, yours could break when taking the old one out.
And no, there's no guarantee what tooth drive gear you have. That would depend on what rear gear ratio the car it came out of was set up with.

 

ok so i got the driven gear off. But i cannot get the clip off the drive gear any tricks.