Center Diff Failures
Here are some pictures of common problems that will eventually cause the center diff to break. The pic below is of the upper center diff shaft. The OEM thrust washer has seized due to bad oil or abuse and welded itself to the gear. This will cause the gear to push itself into the housing and cause a serious clearance problem with the spider gears and soon they will break. Our Torrington upgrade solves this problem. You can see how tiny rollers will last longer than a flat washer. They are also much stronger.
The picture below is of our Torrington unit. We have never seen a Torrington unit fail in any way.
Here is another common problem. Hard launching, and bad fluid will cause fretting of the spider gears. Below is a pic is a spider gear just about ready to blow up. Note the chunks of metal missing from the teeth. Having 4 instead of 2 is always better.
This problem seems to also affect a large number of high mileage and abused trannies. The washer below is a thrust washer for the lower diff gear. They are known to split like in the pic. When they do that, gear clearances become very loose and spider gears can break, just like when the upper gear washer fails.