trans has the gmr 1" chain 3.29 ratio and a unknown reluctor wheel.my car is a gt so it came with 3.29 stock,yesterday i was driving with my gps and i noticed that the speedo was like 7-10 mph fast i've put like 3k on it this way i didnt know it was an issue.When i screwed with it in hp tuners i ended up with like 2.80 fdr to get thew calculated down to 1.0 in 3rd but even then the speedo was off what is the proper way to fix this