RWD diff fluid change

TW, need to call on the think tank.

I just changed my rear diff on my RWD Sport for the first time. Currently at 30k miles. The old fluid only measured to about 2.75 quarts and was quite dark. I replaced with with roughly 4 quarts of AMSOIL Severe Gear 75W90.

Is such a discrepancy normal?

 

No. But you're probably fine catching it so early.

 

Given the relatively low mileage, I can’t imagine that it was changed previously and therefore original fluid from the manufacturer.

 

For reference, I pulled my fill plug at 15k and had to add about 1/2 quart or so to get mine to overflow.
I've read a lot of comments about Toyota underfilling (probably within level range), but yours seem extra low if it was factory fill.

 

30k a lot of miles, esp being that low.

Also, are you sure your diff requires only 4qt? Most all are closer to 6qt.

 

6qt will be total volume for Front and Rear Diff. Since mine is only RWD, roughly 4qt is required. I’ve since seen older posts here in TW with specs ranging from 3.6qt to 4.4qt.

 

mine was low but not that low and took about the same amount, maybe a bit more as i recall, to get it full to the bottom of the drain hole.

 

Toyota nor any manufacturer fills them to the brim, usually 1-3mm below.

 

What a coincidence, I changed mine last week at 30k. I drained it into a measuring container and got out just shy of 4qts.

i was able to put in almost 4 qts before it started overflowing at the fill plug. Truck was level.

 

Cool! I just wanted to confirm was was just remembering that mine used more than 4qt.

 

Better to overfilled than under, yes? I suppose the question then would be, any known issues with overfilling the diff casing?

Seems like quite a few “how-to” vids basically have the diff being filled to the brim of the fill hole.

 

What was the color of your fluid?

 

Fill it until it just starts to flow out the fill hole. Good to go. I do mine every 30k and at 220k on the truck I've had no issues.

 

Yup this saves room for error, but most engineers and manufacturers prefer lower to allow for heat expansion.

I let it over flow simply for visual confirmation when I'm working so I don't forget if I filled it or not.



This 0-5mm spec basically applies to the pinky check. If the pinky can get oil on it, its good.

 

Owner's manual says 3.1-3.2 US quarts for models without the rear locker, so you were about half a quart low if your measurement was accurate.

 

FYI: Dark fluid does not mean bad fluid.

 

Correct, I’d bet OP’s new fluid is already dark in color if drained today.

 

Good to know. I’ve taken the initiative to be more hands on with my truck, hence the noob question. I appreciate the feedback and insight here and am a full on student. Thanks all!

 

Good on you for learning to do your own work! While I’m sure there’s many good techs, shops, and maybe 2 or 3 honest service writers still out there, it seems the trend is moving towards shoddy and/or dishonest work.