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...

 

The best recommendation to make sense of the contradiction in Toyota manual is found at

https://eastcoastgearsupply.com/ft-2536-ecgs-gear-oil-recommendation.html

essentially, when to change the differential oil depends on the temperature the differential has had to endure.

if it was very low temperature, then the fluid stays good for almost ever, if towing or off-roading where the differential may had to work harder and temperature rise, then one has to change it way earlier (manual says 15k miles),
But if temperatures went higher than in those cases, the interval is very short and oil should be changed right away.


Temp Reference Chart – diff oil change frequency

o 170 Deg - 100,000 Miles

o 200 Deg - 50,000 Miles

o 220 Deg - 25,000 Miles

o 240 Deg - 12,000 Miles

o 260 Deg - 5,000 Miles

o 260-300 Deg – 500-1000 Miles until Temp is controlled

Actions:

• install a $50 temp gage on your diff. If your diff regularly sees mileage over 200f change the oil frequently,
• Differential breather: always run a vent to a dry area and insure it breathes easily

https://eastcoastgearsupply.com/ft-2536-ecgs-gear-oil-recommendation.html

 

Did the rear in my 4Runner at 10k and it was dirty. Rear in my Tacoma at 10k and it was clean.

 

I changed my rear diff fluid on my 24 with 20k miles, magnet didn’t really have much on it…

at work we have fleet trucks. Mostly f150s, and some 250s gassers. Some of those trucks are 20+ years old and I know for a fact none of them have been changed and they’re still going lol, don’t know how, but none of them have failed.

 

We have some pickups like that in our fleet also, one with 345K miles! Why does it keep running? It's anybody's guess. The dump trucks and other semi tractors get theirs changed once a year( about 50K-60K, the trucks with manual trans. gets a synthetic 50 weight. Using the synthetic trans. oil, the trans runs a tad bit cooler. Our 4Runner is getting Diff., transfer case, and trans done on the next oil change, 42K. I don't know if Toyota uses pure synthetic but, Lucas or Mobil 1 going back in on the diffs.

 

Did mine at 60K and it looked pretty good. Xfer case and front looked new. Probably only 2K off pavement in that 60K. I do tow over 4500 lbs with some regularity.

 

Gee, I don't know how I survived my 55+ years of driving/hot rodding without changing my diff fluid and breaking in procedures.

The not towing for 500 miles does seem to be somewhat valid.

 

https://www.amsoilcontent.com/ams/lit/g2043.pdf