Differential fluid change.

I just changed mine at 15k. Used 6 qts of Mobil 1

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90. Always used Mobil 1, never had issues. Using the super expensive and hard to find stuff (you know who you are, Amsoil) is overrated, if you remember to change it at the correct interval.

Look at the maintenance supplement in your owner's manual. For anyone driving more than your standard run-of-the-mill highway trips, it is recommended to change the front and rear differential fluid at 15k miles for these trucks. No seepage or water contamination for me, but the front diff had quite a bit on the drain plug, rear had almost nothing. Then again, I have the ECGS bushing...so that could be it.

Also, a forum member did blackstone analysis on his diff oil, and they were recommending changes at the "severe service" interval of 15k miles. An interesting read.

 

I haven't really read all the replies so no offense, but I would stake the life of a fairly expensive component on what you read on the internet. If you don't find an exact match with the type of fluid in your owners manual, you can actually speak to a real live person at Red Line and ask them what to do. I'm a fan of Red Line, not because I actually know anything myself (ha!), but only because it has been touted for years by a BMW guy (Mike Miller) who writes on tech & maintenance issues in Roundel and Bimmerfest magazines. He swears by the stuff, and if it's good for an M5, good for my Taco!

500 miles is awfully soon too; most "experts" I think would say it's probably not 100% broken-in yet at that point. The book says 30k, but I did my first fluid change using RL in both my manual trans and diff at 5k (then again at 30k and every 30k since..). The diff was disgusting, the magnetic plug was maxed out and the fluid discolored. Ever since, my diff plug and the old fluid has been clean, so just about all the wear (at least in terms of visible metal particles) seems to have occurred before 5k. Point here is definitely don't wait until 30k for the first change!

Mike Miller has often said that routinely changing manual trans with synthetic redline will make shifting smoother than new, even after 100k miles (assuming you don't shift like a gorilla..), and I agree. At 165k, my manual is as smooth as silk; no "notchy" shifting, etc. I've always had a noticeable level of gear whine coming from the diff, but that seems to be standard on these trucks. At least it's not gotten worse, and no problems so far back there.

Anyway, good luck with it, and good move in my opinion to DIY this sort of stuff and at shorter intervals than the mtc schedule claims, especially after break-in.

 

Just had to comment on this 4 years later in case someone reads the above quote and believes it’s valid. No Toyota tech is going to send out your fluid to confirm its authentic OEM. Unless you used beef gravy, its going to get dumped in the pan and mixed in with fluids from a dozen other cars. They would have zero reason to forensically trace the exact fluid used regardless of warranty. So as long as you dont use gravy, 75-90 will be ok in this case.

 

i did

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 in the front & rear axles and transfer case at 60k, the dealer said they use that in all of them and to add an LSA to just the rear case.

 

So, you saying… we can use gravy? Chicken or beef? Hmmm… now I’m hungry…

 

Gravy does sound good, as long as it's not that nasty giblet kind at Thanksgiving haha.

There was a member with one of the early third gens who had this happen to him and ended up fighting the dealership to have the diff replaced. I can't remember the screen name or even the out come of his situation at this point though. I ran the 75 90 with no worries.