I just swapped out my fragged "world class" T-5 for a slightly older "non-world class" T-5. The gear ratios feel the same, but my speedo is reading about 5mph under @ 40, 10 under @ 60, and gets worse the faster I go.
I can turn a wrench, but in this case I don't even know what I need to replace.
The car is bone stock with a 3.08 rear, maybe a set of 4.10s would get the job done? Any help at all would be awesome, thanks!

 

Take the speedo gears out of the old transmission and put them in the new one.

 

Do you have to open the case to swap these gears? Where are they, where the speedo cable connects to the tranny?