2020 TRD OR rear diff fyi

I suspect this has been noted elsewhere, but I'll toss it out there...

I change diff fluid early on new trucks, because they tend to see a lot of break in debris early on, and this one is no different. Good amount of wear material on the magnet and the fluid looked as you'd expect, even after only 3000 miles. What was a bit more 'exciting' was that I only got ~3.5 quarts out of it, and put ~4.3 quarts back in it.

While I'm not too concerned about it detonating, it doesn't strike me as ideal, so you might want to change it. It's pretty trivial if you're used to doing oil changes.

 

Sounds like you overfilled it.

 

You can't really overfill the rear diff unless you parked it facing down an incline. It's made to be filled up to the bottom of the fill hole. The stated capacity is ~4.2 quarts.

Since this is the internet and it's probably irrelevant I probably shouldn't mention that I'm 45 and have been spinning wrenches for the last 30+ years, but hey, what the hell. You only live once.

 

So if it’s meant to hold 4.2 and you put 4.3 , one it’s overfilled and two unless you tore the diff down and degreased it completely it’s overfilled

 

So we're arguing about 100mL's? Pretend I was never here... I have better things to do. Bye!

 

So that's a bigger sticking point than being underfilled from the factory? Lol

 

Don't third gens have independent rear suspension?

 

For some reason I have it in my head that the "dirty" oil in the diffs, especially with low miles, is a lapping compound. I always wondered if that's where some of the louder diff whines come from. I'm sure some of the more technical Toyota savvy guys will plumb me up though.

 

No.

 

Welcome to TW and just ignore the trolling, it's all in fun.

You're right that it has been documented that alot of tacos come off the factory floor under filled with fluids. My transmission fluid was under off the factory line. When I changed it I had to put more in then came out, just like you. Good thing you checked and I applaud you for bringing it to the attention of others.

 

300mL

 

Overflow valve

OP, who is new to TW so it's best practice not to poke fun at yet, has been wrenching for 30 years so he knows what he doing. Therefore it is impossible to overfill it by design.

 

https://www.tacomaworld.com/threads/fluid-specs-and-capacities.607434/#post-20514318

Looks like you did, overfill, at least a bit

 

Is anyone that says he overfilled it actually changed differential oil?

You'd have to pump more in than immediately screw in the plug as it comes rushing out all around that plug and down your hands.

 

Yes, we get how diffs work.

 

Well than you know it is almost impossible to overfill it, especially an experienced wrencher, unless you screwed the plug back in as it was gushing out all over you.

OP was trying to make a point his came under filled off factory line. If I had a new truck I would appreciate someone pointing that out versus learning at 30k.

 

Absolutely...
It's the conflation of quarts and liters I'm harping on.

 

That's the whole point. Book calls for 3.8-3.1 depending on config and he drained 3.5 seems spot on. So apparently it is easy to overfill, assuming his numbers are right.

 

I just did my 8.75” rear diff today and pulled out 3.8L after jacking the drivers side axle to tilt the last few drops out.

I overfilled mine till it came out the fill hole, then put the plug in and called it done.