Hey guys I just put new strange axils in my 72 chevelle. It has a 12 bolt locked rearend for racing. One of the originals was a little twisted they said it was a common problem. When I replaced the twisted one the car drove fine fixed the original problem and all was good. But I went and replaced the other side because I ordered 2 new axils and after about 100 feel of driving the rearend locked up solid. The original axils had XX 29 stamped on them the new ones have 30 (and then I think XXY not sure they are in the car now) I was wondering if Strange sent me the wrong axils what does that 29 and 30 mean? If anyone has any info it would be really appreciated I am at a loss.

Did you put the c-clip back in and did you torque down the retaining bolt that holds the pin in which holds the axles and the spider gears in place? I don't think your problem is the new axle, I think the problem is something in the differential was not replaced properly when the 2nd axle was put in. If the c-clip fell out and got jammed between the ring and pinion gears: locked axle (and the possibility of the axle coming out of the housing). My guess is that the pin was not bolted in properly and worked it's way out of the differential and locked it up against the housing.

Have you pulled the cover to see why the differential is locked up? Until you do, everything is a guess as to why it locked up.

Thanks for the suggestions but it turns out strange sent me the wrong axils. I hope theres no major damage they admited to the mistake which I can understand I just hope if something is broke now due to there error that they step up and pay for it.

Can you explain how the wrong axles caused the differential to lock up? I'd think, wrong axles or not, if you could install them into the housing and the splined end fit in the differential and the other end fit in the bearing there would be no reason they would then cause the differential to lock up. I'm really curious on what happened.

The teck guy on the phone sayed they were each longer and wound up binding in the middle I agree I am also confused but as long as the new ones work its all good with me I just hope there is no major damage to the rest of the rear.