This might be a stupid question but here it is. What kind of difference would there be in a t-5 with a .64 od and a t-56 with a .62 od.

 

One will just be a little bit higher of a gear in overdrive. IE option a pulling 3k rpms at 65 and option b pulling 3100rps at 65.

correct me if im wrong plz

 

not noticable at all most likely

 

The t56 also has that extra 6th gear so the feel is different when driving it. Although in a track purpose it could yield slower times do to shifting more but on the highway it can make a nice difference.

 

How would if make a difference if the od gear difference is only .02? Also what is the 5th in a stock t-5? Thanks

 

These numbers that you are quoting represent the percentage of rpm drop from your 4th gear, which is a 1:1 ratio. For example, a .75 fifth gear will produce 75% of the rpms that the 4th gear will at the same speed, or a 25% drop.

Your stock OD gear is .63, which is termed a 37% overdrive. The .62 6th gear is a 38% overdrive. From the seat of your pants you will not feel a shred of difference. However, the 6-speed has a step-down 5th gear overdrive that is useful if your engine is falling on it's face when it suddenly drops more than a third of its rpms. The t56 is not as efficient as the t5 at getting power to the rear wheels as it has heavier internals and more parasitic loss.

Put another way, this would be like comparing the performance difference between a 3.50 rear ratio and a 3.51 rear ratio. Hope this helps.