Differential Break In

[spasm3]

If i were to change the gear oil in my truck ( the one in my signature ) to say high performance lubricants, what mileage should i wait until its finished breaking in?

Its used mostly for towing, I have about 2200 miles on it now. When would it be done shedding metal?

I think once its broken in , i would use HPL Differential life, and change it say every 25k.

@High Performance Lubricants and or @Zaedock feel free to chime in with your thoughts.

 

[MRC01]

What is the factory gear oil change interval? Have you got some duty cycle or application that puts a lot of stress on the diff, like towing? The note in your sig suggests that you changed the ring & pinion gears to get a 4.1 ratio?

The reason I ask...
I think most though not all of the break-in has already happened at 2200 miles. You've got the heat cycles to harden it and initial wear to smooth the surfaces. But with cars I like to wait until around 30k miles before changing the differential and transmission oil. That's because 30k miles is shorter than the factory gear oil interval, so it does no harm, and ensures complete break-in.
Once it is broken in, after the initial gear oil change you might never see additional wear. So 25 k interval sounds unnecessarily short.

I changed the diff oil in my daughter's 2004 Subaru at 30k miles. The factory oil came out black with some tiny/fine metal particles as expected. At 100k miles I checked it. The oil was still clean & clear like brand new oil, no darkening or discoloration, and no discernable metal particles at all.

 

[wpod]

I would change it now. There is no reason to run the wear in products any longer than needed.

 

[Cujet]

Although this is a different application, helicopter transmissions use the classic "ring and pinion" gearsets. They occasionally produce shavings of metal for the first 150 hours, and after that, tend to operate for many thousands of hours without making any metal. So, about the first 5% of the gear's overhaul limit of 3000 hours (not lifespan, as they can live 15,000 hours) is what we see.

I'd say between 5,000 and 15,000 miles is a very safe bet. Although, I'm one of those who likes to change fluids early, "just in case". Doing so has served me very well. So if you feel like changing it now, why not!

 

[tcp71]

I waited until I hit 12k miles for mine.

 

[spasm3]

Thanks for the replies, i will put about 3k a year on it, based on my driving so far. I bought it in Aug of 21, and have almost 2300 miles on it now.

 

[SwampSurvivor]

I recently regeared my jeep. I did about 100 miles of short trips to heat cycle the gears a few times, then did a rock crawling trip and took the covers off and changed the fluid.

 

[2strokeNorthstar]

I had the gears changed in my truck and the shop I went to does nothing but differentials. His response was, “change it if you want in a few weeks or you can wait a few thousand miles. It doesn’t matter, changing it is more than most people ever do.” I changed it with the next oil change. That was probably 10 years ago

 

[Zaedock]

I'd say between 5,000 and 15,000 miles is a very safe bet. Although, I'm one of those who likes to change fluids early, "just in case". Doing so has served me very well. So if you feel like changing it now, why not!

Happy Easter everyone!
I think Cujet is right on. I would change around 5,000 miles. I tow quite a bit and haul firewood weekly, so I change the diffs in the 'ol Ford every 25-30K miles. We're moving my son to Dakota State this Fall and I'll be completing the third change in 78K miles. When I had bought my F150, I had a leaking axle seal that my dealer replaced around 6K miles (they actually did both seals), which took care of the initial break in change.

When I built the rear axle in my Jeep, I drove a few hundred miles and changed the fluid.

 

[Zaedock]

Here is a paper (a bit older, but IMO still applies) from Amsoil.

TSB Diff Oil Change

 

[Trashman]

I would change it now. There is no reason to run the wear in products any longer than needed.

This