Differential break in

Question for you guys. I don't think Toyota has a break in process for rear diff or recommend changing gear oil out early.

ECGS has a very specific break in period. I have always changed the gear oil out early for piece of mind to know at the correct level and get and break in metal out.

I have to assume 99% of users don't change it out early or ever. Thoughts? Questioning my OCD and if it matters on a new vehicle.

 

I think the machining on the OEM gears must be better/more precise or they run it through some pre-install break in process. I changed mine out at 30k and it was still pretty clean and no large particles so I would not see any need to change oil out so early.

 

Toyota's owner's manual just says not to tow for the first 500 miles, which is a subset of the typical differential gear break-in process:
https://www.usastandardgear.com/blogs/new-gear-break-in
https://www.revolutiongear.com/ring_and_pinion_break_procedure
https://www.yukongear.com/help/faq/...he-break-in-proceedure-for-a-new-set-of-gears

My Tacoma (which I bought new) was driven over as a dealer trade, so it had 300 miles when I took delivery. I changed out the diff oil at around 600 miles. Laid a styrofoam sheet over the ice in my driveway (mid-January) and got it done. The 4Runner was bought used so I don't know how it was driven during break-in. The tall 3.73 gear ratio does contribute to less heat output.

 

Did my three gear boxes at around 25k+. Oil was still clean. Rear a bit darker shaded. Front and rear drain magnets had a little metal paste which I cleaned off.

Factory recommendation is 30k.

 

Did mine at 25k, bought it used also. Front differential was definitely more metallic than the transfer and rear but otherwise things were fine.

I wouldn’t sweat it, I believe there’s a severe service recommendation of 15k in the manual but really, whatever makes you feel better, same with motor oil like that whole first change at X miles or Y miles. Probably the biggest worry would be water ingestion.

Now that I think about it, I don’t think my dad ever changed the differential oil in his RAV4. That’s gotta be hitting 200k miles soon…

 

Just drive. I planned on 60K changes but I’m almost at 70K. I’m lazy but it’s also not super critical.

 

If you are a serious off-roader and towing kind of driver, I say do it every 50K. There are people that never change this and it is fine.

The ECGS recommendation is for the gears they sell which they don't do this final polishing step and other treatments and that's why they even specified a thicker oil than factory, 85w-140. How do i know? I regeared both the Taco and 4R last year.

 

Changed all diff/transfer case fluid with just 3500 miles on mine. Rear diff definitely have more metal on the magnet. I think this way: diff fluid is pennies compared to the gears, thrust bearings, seals, labor, etc. I changed out the rear diff again at 3650 miles and still find the magnet full of metal (reused the fluid in my daily Frontier). Yeah I have severe OCD...