Hey yall. I was regretting having to ask on forums but I finally cannot figure out some gear whine I am having, or at least the next steps to solving it.

I swapped a Ford 8.8 31spline from an Explorer into my XJ. I gutted it and installed an OX locker with a Manually actuated cable and 4.56 Yukon Ring and Pinion. Along with that, I did not want to shave the ring gear so I installed the Yukon C-Clip Eliminator kit with Chromoly shafts. It also has Teraflex Disc Brakes swapped from the stock drums.
I used professional tools to install everything correctly! The only tool I did not use was a housing spreader.

Here are the issues so far, I get a high gear whine at exactly 30 mph. It fades away in pitch when you move farther from that number 30.
I also have a very low grind noise when I am traveling over 60pmh and release my foot from the accelerator and let it coast at high speed. When pushing the accelerator the low grind goes away.
Both of these issues sound like they are coming from the rear, and I assume the new axle.

When I installed the gears the wear pattern was PERFECT. I was stoked. After the 500 mile break-in, I cracked the diff cover and check the wear pattern. Now the wear pattern was slightly off how I had installed it. I will attach before/after pics of that pattern. My best guess is that this is the cause of the issues and I need to re-install these gears. Thoughts?

Initial Gears Wear Pattern before driving:




Gear Wear Pattern Post 500mi Break in:




Now after looking at the Yukon wear pattern manual, it seems that my Ring Gear is too far from the Pinion. I'm not sure what would have caused that but I could be wrong and that is not the case. Please let me know what you guys think based on the wear pattern!

 

did the crush sleeve actually crush ? this is a common problem with the 8.8 set up . I had the same problem (the crush sleeve didn't crush on mine ) so I went with a crush sleeve eliminator kit from summit racing and set it up again and have had 0 trouble since .

 

 

what happens is the crush sleeve will not crush then when you drive it and get on it it crushes and then the pinion becomes loose causing all sorts of problems

 

 

gotcha didn't it !! now get ya a crush sleeve eliminator and set it up 1 more time and it will be good forever