hey guys just did mine and noticed something weird.
After the oil change the diff started to leak a little bit from the drain plug.
I did replace the washer and torque the plug back to spec...did any of you notice a small leak after the oil change?

It definitely shouldn't be leaking from the drain plug. I assume you wiped everything down real well. When filling, it should have overflowed back out the fill hole, which can cause a mess making it difficult to detect a leak if you haven't wiped up the excess fluid.

The bushing could be failing, I guess, but I'm no expert. I don't know if the leaking fluid from a failed bushing can make it look like the drain plug is leaking. The photos I've seen certainly don't appear that way.

Here's an example photo of failed bushing

it's definitely leaking from the drain plug but it's minimal so I guess I'll have to check it more often...Im using royal purple 75w90 btw. thanks for the help

How do you know when to stop adding more fluid ? does it just spill out the fill hole ?

Yes

I normally give it a etxtra pump or two after and get the whole sealed as quick as possible. Also make sure that when you are filling the diff that you have the car completely level. very small detail that is easily missed!!!

Rear dif and Trans completed
 

Well, I just finished swapping out my Rear diff and manual trans fluid (28,000 miles) to RedLine products. Called Z1Motorsports and told them what I was doing. They sent me everything I needed cheaper and faster than I priced it locally! Very helpful staff and super pleased with how freak'n fast it arrived. I bought a $10 siphon from Pep-Boys and it work flawless. The entire process was pretty straight forward. Very pleased. Thanks for the write up again and thanks Z1Motorsports! There were lots of posts/comments on WHICH redline fluids to use. When I called Z1 I asked about the difference and they explained it to me and sent me exactly what I was looking for. :tup:

So what did they send you? Redline says what to use on their site.

that they do. I went with the T-85 for the trans and GL-5 gear oil, 2 quarts 75W-90 synthetic for rear diff. I'm pleased with the customer service I received. This is the first time I've used Z1.

The diff on my gf's 370z looks just like with the oil drip streaks. Her diff oil hasn't been changed and she claims it's not accelerating as it used to.

Wondering if she has a failed bushing problem.

Hey guys, my car have 21k miles and thinking about changing the diff soon. Which Diff oil should I use? What do I use to fill it back up? Thanks for any help guys!

Did you not read the very first page? :icon14:

Nope....what did it say?

All of the answers to your questions are in the very first post.

Anywhere sell 80 90 gear oil for the Z? When I do mine soon I would like to use this.