So I picked up a NIB Eaton Posi and Motive Gear 3.73:1 Ge****t from a guy who needed some money for very cheap. They are for GM 10-Bolt and the Posi says it it for 30 spline axles. I figure I can throw a 10 Bolt under my coupe and it will be plenty strong since the car is so light. I have a couple older 8.5" 10 bolt housings and center sections (79 olds and 77 Nova). When I look up the posi unit it says it fits 1988-Up GM Car/Truck. The Eaton part number is 19559-010. So I am wondering if I can make this posi unit work in one of the housings that I already have or if I need to look for a newer unit. What are the differences? Is it just axle spline? I will be buying new axles anyways, so I should be able to order whatever I need. Any advice would be appreciated. Thanks
I think the main difference is the 1988 up axles were 30 spline and the earlier ones were 28 spline (but you can convert to spline). I think the later units also used that awful limited slip unit that always goes bang. Also I think the bearing sizes change internally so you may have to get new bearings as well. I think some of the full size truck and 4x4 s-10s still had 8.5 ring gears. none of the p***enger cars though.
Hey guys, you're sitting in front of the greatest research tool since they invented libraries and you can't find out what's what? There are 4 different 10 bolt rear ends, but the Eaton unit you have is a 3 series carrier that fits a 8.5 rearend with 30 spline axles. It will fit any 8.5 rearend if you use the right custom axles. Larry T
Not true. There were a lot of 10-bolt rears pre-88 that were 7.5 and 7.65. In fact, most of them in the 80's were.
I'm pretty sure the early 7.5 gears (Monza) were different than the 82 up Camaro/S-10 gear. And you have 8.2 and 8.5 10 bolts too. Look at a Richmond Gear catalog, it should break them down for you. GM pickups used the 8.5 rearend for quite a while. Larry T
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