Hey challenger fans, I've been doing alot of research on rear end gear swaps--alot of us want to get rid of the 3.06 gear--here is what I know for sure. The Richmond Gears DO NOT fit the Getrag rear on the SRT's--the 3.73 & 3.91 rears from the R/T 6 speed cars not only don't swap with the auto's rear--but the Diablo Tuner DOES NOT recognize those ratios so it won't tune.Also I'm pretty sure the number of splines on a 215mm is different than the number of splines on the 210mm rear --so if you purchase the 215mm for a R/T automatic,plan on buying new axles also.If anyone else would like to add info I missed --please do
