Having travelled the requisite 500 miles to break in my new 4.88 gears (you may want to read "New Gears - 4.88's and an ARB front locker" and "the first 500 mile break-in" if you haven't already), it was high time to change the oil in the rear diff - hopefully uneventfully - to clean out any metal and other gunk that may have been present as a result of the break-in.
Toyota conveniently calls for 90W oil in the differentials, and that's hard to come by - at least for me, locally - so I decided on Lucas 80W-90, non-synthetic. I also picked up a set of gaskets/crush washers necessary to change the oil in both diffs and the transfer case, even though I'd only be using the rear diff pieces for now.
I wondered if I'd also need a pump to fill the oil, but I figured I would just pour/squeeze it in from the 1 quart bottles - it seemed like there should be plenty of room.
Parts in hand, I loosened the 24mm fill plug uneventfully. No oil came out, and nothing exploded, and the plug was relatively clean (as expected). Plus, I knew that now I'd be able to refill the differential, at the very least.
Next was the drain plug. Also 24mm, I tried to be quick so as to not get oil all over everything. It was 37°F out, so I'd driven the truck around for a few minutes to warm everything up and get it flowing. Plug removed, the oil flowed right out and into my waste container.
The drain plug was definitely dirtier than the fill (again, expected), and the magnet was covered with a bunch of sludge that I removed and spread on a piece of aluminum in order to see if there was much metal. There was nothing grainy except for a single metal flake. All-in-all, also relatively uneventful.
With the old oil drained, a new washer went onto the drain plug and it was reinstalled. My hope that I could just dump the gear oil in was validated, and the fill plug + washer were reinstalled.
Total time - 10 minutes.
Sense that everything's still OK in the diffs - priceless.
Hello, I just changed the gear oil in both differentials and transfer case. The oil looked good BUT I had a pretty large chunk on my drain plug in the rear differential. Looks like a tooth broke off a gear, full width and maybe 1/4" deep. I didnt have time to crack open the diff to look inside, so I filled her back up. I havent noticed anything abnormal in drivability. What would you do if you found this in your diff?
That's definitely something I'd want to take a look at if I found it in the rear diff. Do you ever recall hearing a loud bang (that might have been the tooth breaking)?
The nice thing about the rear diff is that it's reasonably easy to access/pull apart. If you're not familiar with the process, it's:
Assembly is almost as easy, just be sure to clean off the mating surfaces well (razor blade) and use some Toyota Black FIPG (00295-01281) to seal the 3rd member to the diff housing.
It's definitely a bit of work, but it'd really suck to have that broken tooth lead to something more catastrophic.
On the flip side, if you never noticed anything abnormal... you could pretend you never changed the oil and just keep going. 😉
Thanks for sharing. I dont recall any abnormal noises from the rear. Hard to tell if it happened during my ownership because Ive only had the truck for a year. I helped a buddy change the axle bearings in his ford but that is about the extend of my experience working with differentials. I have an open diff in my Tacoma and I have been wanting to upgrade to a true trac for a while now. I just read your post on regearing and im in the same camp as you. Im in eastern WA and I might just give Carl at JT's a call. I wonder if i could get away with driving it there in its current condition.
JT's is no longer in business, but I think there's another offroad place that is now in that location. I'm not sure where Carl went, but if you can find out where he is now, I'd go to whatever that shop is. That dude is great.
I'd have no reservations driving across the state in the current condition; that's not very taxing on the diff (since you're mostly just maintaining speed on the highway) and I think you'd be fine.
Well, thanks for all the help. Ive got some work to do. Would love to join on an adventure if you're ever heading out towards northern Idaho.