I thought 9 bolts were supposed to be the stong third gen rears.... I now have a 9 bolt with broken spider gears all of them and the differential case that holds all the stuff inside has marking and gouges in it like the hole thing was moving inside the case wierd.... well the posi was fun while it lasted..... i guess ill ut the old 10 bolt 2-73 non posi drum brake rear pos back in

 

What spline did you have it in and what parts? 9 inch rearends is what Nascar uses. 9 inch refers to the case, 9" of circumference. However, you have to build them to be strong. You can't put 27 spline axles and expect them to hold up. You need 35 spline with heavy duty parts to take the abuse. Such as performance carrier bearings, axles, etc. They are one of the strongest rearends except for the Dana 44 and Dana 60 so it shouldn't of broken it properly maintained and built right.

 

He said 9-bolt rear end, not 9".

That said, my thought on the situation are this: stuff wears out over time. It's just a fact of life in this hobby... nothing lasts forever, even when treated with care. The risks of breaking something are even higher when you do something that pushes parts to their limit.

9-bolts are definately stronger than 10-bolts in stock form, but when the amount of power you are making warrants an upgrade to either rear, the 10-bolt should be the rear to go with. The cost of the 9-bolt's parts will be signifigantly harder to find and more expensive than any 10-bolt rear, which can be easily beefed up with common aftermarket parts.

 

ya well i dont think im gonna fix the 9 bolt i think im gonna go aftermarket unless i can find a 10 bolt posi thrn build it oh the axles were fine on the 9 bolt just the spider gears are all chipped and the bearing looked like theve been hit with a hammer lol

 

Nine bolt parts are expensive for sure. With serious power I'd sure look into a converted 9" style rear. Big bucks but it would last about forever.

 

just to clear this up 9" stands for a 9" ring gear, the case is larger than 9"s.

To clear up a little more a dana 44 is right on par with a 10 bolt. Dana 44 center sections are nice though I mean look at vettes!