I've installed my 2nd new ring & pinion. car has a 350/Th350 in it. I wanted to go positrac so i installed a detroit truetrac in it with 3.23 gears.... that combo turned out to be WAY to high rpm's at cruise speed. So i dropped down to 2.73... when installing i noticed after i got the setup (where i felt was correct) pinion preload was spot on, pattern was decent, backlash was good.... but when i would turn the carrier with no axles/no driveshaft connected... to check the pattern it would spin freely until about the very end of the carrier.... it would like "grab" the last part of the ring gear teeth. it was 1 specific section of the ring gear that it was grabbing. To me that eliminated the bearings, driveshaft, axles.... So I either didn't set it up properly or i got defective gears. I am puzzled as to why the gears would "bite" or grind closer/grab that 1 particular section of teeth... it results in a vibration when i drive... the rpms at cruising are wonderful... i can go 70-75 mph at 2800 rpms

Any suggestions? defective gears? something in setup needs correcting?

 

make sure axles are not bent. i would suspect the gear is faulty, could it be the gear is not installed flush.

 

As Craby suggests, check ring gear.
You can put dial indicator on the top of every tooth and spin for one rotation and measure tooth height as it sets.

I would not think any more than 0.002"? variance?
There may be a burr on gear face or carrier - all should be flat.
If you take ring gear off carrier in the journey, place ring gear face onto a sheet of glass with emery paper and do a circular motion across emery paper and view sand marks on gear.
Should be 100% coverage.