9" side gear?

[jguajardotx]

Are older model 9" 3rd members different than newer models? I ask because I replaced my 28 spline 3rd member with what was supposed to be another "28 spline" 3rd member recentley. The axles would not grip though. I was thinking maybe the newer one I installed was a 28 spline but maybe came off a newer model. Is the bore on the sides where the axles enter different from older models to newer ones? Is this a dumb question? Sorry just fusterated and confused on whole rear axle thing!

[Thunderfoot]

Most newer 9" are 31 spline... There is no difference in the size from early to late but there is a size difference from 28 to 31 spline. The 31 are bigger diameter axle, so if you could get the axles in but they aren't connected, then is sounds like it is a 31 spline third member...

[jguajardotx]

Thanks, BIG help