Axle spline count question.
I am getting conflicting information and have not found a definitive answer. Planning on putting a new, better rear diff in my '99 Tahoe Z71. Some sources say 28 spline and some say 30 spline. I've gone through several vendors' sites and have found both to be true. I am trying to avoid pulling an axle just to check before ordering the diff and installation kit. I've never had trouble with other vehicles I've done this for, but my research hasn't given me a conclusive answer.
So...which is it...? The truck was built early in '99 in Mexico. Push-button 4wd. 3.73s. Tow Pkg. There are some codes on the housing, but nothing I have found that translates to determining spline count. Maybe I'm looking at the data wrong...
Assuming we're talking about the ten bolt housing that came in most 1500s, it's 30 spline. I believe the 28 spline version of the 8.5" 10 bolt was used in early (like pre-'88) trucks and passenger cars. Page 10 of the Eaton Differential Application Guide can confirm this for you.
http://www.eaton.com/ecm/groups/public/@pub/@eaton/@per/documents/content/ct_128302.pdf