Speedometer says slower than I'm actually going.

[stang7373]

Last year I blew my tranny. 3rd gear was destroyed. So this year I installed a used tranny from a 92, which is a little better. I think i put the correct drive gear in for the tranny, pretty sure it was yellow (2.73). A maroon one came out from the old tranny (2.73). When I drive, the speed is wrong. For example if I think I'm going 65, I'm really going about 75, and if I think I'm going 40, I'm going about 45/46.
So any suggestions? Maybe a different speedo gear but i don't know which one.

 

[TRWXXA]

The DRIVE gear is on the tranny's output shaft. The DRIVEN gear is on the end of the speedometer cable. I'm assuming, since you mentioned the maroon gear in the new tranny, you're talking about the DRIVEN gear.

If your speedometer is reading too slow, need to replace the driven gear with one that has FEWER teeth. You might want to try the maroon (16-tooth) gear from the old transmission, instead of the yellow (18-tooth) gear you have in it now.

Theoretically, a '90+ 5-speed should require a 17-tooth (white) driven gear for a 2.73 rear end.