Weekend Warrior Maintenance - Coolant and Rear Differential

4.6L 2WD Double Cab

Did some long overdue maintenance today replacing the coolant and changing the rear differential oil. I thought I would share my experience for others. A lot of forums and videos I found were more geared towards the 5.7L engine.

I bought the truck in 2015 with roughly 50k miles on it. I'm don't believe either were done before I bought it and I have not done either since owning the truck. Truck has 170k miles on it now. The diff oil may have been done since the truck was certified pre-owned when I bought it.

I started with the coolant and ended up doing both sort of simultaneously. I mostly followed this video here: https://www.youtube.com/watch?v=OivwKhMyLxs

With the coolant never being done before, I hesitated to drain the engine block on each side via the brass drain plugs, hearing that they are prone to breaking. I drained the radiator first and the coolant coming out was pretty clean for the most part (pictures below).

I decided to drain the passenger side drain valve after realizing the driver side is mostly buried behind the heat shield, at least on my truck. While the passenger side was draining, I jacked up the driver side to help it drain. Between the radiator and the passenger side drain, I got roughly 2.75 gal of coolant. I decided not to mess with the driver side, knowing the truck should hold roughly 3 gal.

I drained the overflow tank as well and then filled everything back up per the video. The truck seems to be running great after a test drive and the temps look normal. I will keep an eye out to make sure the levels stay good.

The passenger side drain took a while to drain so while that was going on I moved to the back to drain the rear diff. I mostly followed this video here: https://www.youtube.com/watch?v=XtBw29bA6ug

The oil that came out had a smell and was dirty as expected, but didn't seem too bad given the time it's been in there (picture below). Make sure you crack the fill plug before the drain just in case you couldn't get the fill plug off. I replaced the crush washer on the drain plug before replacing. There was some metallic on the plug as expected.

When filling the diff, gravity is working against you. The guy in the video uses a drill pump. I bought a hand siphon, but I was worried about the effort needed to get the the thick oil through the siphon. I decided to cut a part of the tube and dropped the spare tire. I used a funnel just above the diff and took my time to pour the oil in there. The diff took pretty much all 5 quarts I bought before starting to flow out. I replaced the crush washers and sealed it back up, cleaning off the diff after.

All and all this was pretty easy, just need to take some time to not break anything. Probably saved a few bucks in the process. The coolant was $28 a gallon from the dealer. The first dealer questioned why I wanted 3 gallons and I only walked out with 2. You need 3. The Toyota diff oil is very expensive and harder to find from what I've heard. The video says that the Toyota dealer the guy went to used the Redline. I paid just over $100 for the 5 quarts from O'Reilly using a coupon code.

Let me know if you have any questions or comments. Happy to help however I can.

 

Good job... when the sky river quits for a few weeks and the temps are in the 60's, the coolant needs flushed as well as the trans.

I'm pretty sure both are pushing the 13 year mark! It's got 107k now... Oh and the brake fluid needs dumped!

OP - don't forget the PS fluid! I was lazy and used a pump to empty it 5x vs disconnect the return to prevent mixing old and new...