Yukon Gear FAIL! at 50k miles

[Bbannongmu]

Interesting to hear you say that. I was told I was worried about nothing on this forum when I said I was worried about pinion input speed as the justification for why I went with 4.56 gears as opposed to 4.88s or 5.13s

I don’t think this is a 5.13 pinion strength problem - it’s a Yukon quality control problem
I think if the gears aren’t made from Chinesium, 99.999% of people will be fine since it’s a let’s say 5% mass/size difference between 4.88 and 5.13. Nothing I was doing (commuting/daily driver) was anywhere near 95% or should have made a pinion detonate.

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[Flyin6]

Just or offer the alternate view, I am using 5.13 Yukon gears in my JT. I have wheeled it quite a bit, but only around 20,000 on those gears. I started using Yukon stuff around 2012 in volume and parts here and there before then. I really haven't seen many failures, but one lunch box locker and a R&P in a Toyota axle.
I hope you have better luck going forward.

 

[Bbannongmu]

Just or offer the alternate view, I am using 5.13 Yukon gears in my JT. I have wheeled it quite a bit, but only around 20,000 on those gears. I started using Yukon stuff around 2012 in volume and parts here and there before then. I really haven't seen many failures, but one lunch box locker and a R&P in a Toyota axle.
I hope you have better luck going forward.

I’m glad they are working for you and I hope they work out. Yukon used to be great but sometime during the pandemic their production and quality control went south. I had 45k miles of light towing, DD and off-roading trails on my gears and thought I got good ones. Then one day on my way to work the pinion detonated with little warning. I thought I had an exhaust problem until a few minutes later the rear started to clunk. The bearings were fine, fluid was fine, we had a good set up and pattern/backlash set up by a seasoned pro. From repeated online reports, it seems like there is a quality problem with Yukon pinions - likely a metal quality /stress fracture/machinibg problem or something. I had to completely replace the rear axle because everything was destroyed - Yukon only has a 1 year warranty and had no interest in helping me. For me Yukon was a $5k mistake

 

[Wheelin98TJ]

On a Dana 44, some believe the pinion gear is too small for long term durability in ratios above 4.88.

Interesting to hear you say that. I was told I was worried about nothing on this forum when I said I was worried about pinion input speed as the justification for why I went with 4.56 gears as opposed to 4.88s or 5.13s

I don't think there is enough strength difference between 4.88 and 5.13 to warrant choosing one or the other for that reason.

The biggest factor in gear set strength is the tooth contact surface area. I think when people conclude that 4.88 is stronger than 5.13, they are just looking at the pinion head and thinking "yup, it's bigger".

I reached out to Dana about this. I'll post when I get their response.

 

[arosen1997]

I don't think there is enough strength difference between 4.88 and 5.13 to warrant choosing one or the other for that reason.

The biggest factor in gear set strength is the tooth contact surface area. I think when people conclude that 4.88 is stronger than 5.13, they are just looking at the pinion head and thinking "yup, it's bigger".

I reached out to Dana about this. I'll post when I get their response.

My concern wasn't even the pinion strength but the bearings and their limiting speed being splash lubricated.

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