The Detroit TrueTrac Limited Slip is an all gear driven clutchless differential. The TrueTrac will automatically provide smooth transfer of power from the slipping wheel to the non slipping wheel to help you out of a jam. With no clutches to wear out, you will have a dependable long lasting Limited Slip differential.
The GM 12 Bolt rear axle has not been in production since 1981 and was only in 1/2 ton trucks and blazers. unless somebody swapped it into your truck you should have either a 8 lug 9.5" 14 bolt or the 10.5" 14 bolt rear axle. the correct true trac for the 9.5" is the EAT914A538 http://jo.my/9ynxut. the 10.5" can be identified by the big hub that sticks through the rear wheels with an additional 6 bolts in it. there is no Truetrac for them but i gave you a link to what is available for it http://jo.my/fqrvyu
The Eaton Corporation has enjoyed over a century of innovation and is in the business of powering Jeeps with a top-rate lineup of lockers, open differentials and limited slips. Traction performance is critical while jeeping and we carry Eaton components for upgrading vehicle traction. Compatible with different axle splines and various gears, these parts are often rebuildable and are top performers on and off-road. Eaton's rich tradition of engineering innovative, dependable products extends to off-road parts and accessories for 4x4s and they have evolved to become the industry standard in differentials, lockers and limited slips. Shop Eaton Now