Hey Mr. Nismo...liked your homemade ramps. Now I wish I would've looked around my garage for the spare wood I had, but the Rhino's work for me just fine.

Same as everyone else...pretty nasty fluid coming out and a gunky bolt after 17k miles. I'm not sure if I've heard anybody talk of noticing any after effects from the change but for some reason my car does seem slightly quieter with the new redline fluid in there. Maybe I'm just imagining this.

Also, anyone have recommendations on getting the engine bay "shiny"? I use a nice citrus cleaner as my degreaser, but was wondering if anyone has recommendations on a detail spray. Thx.

I'm gonna make an observation here based on what I've seen. I've never changed my Diff fluid, at 13K I'm probably not due unless I'm bored one day. My opinion is that when guys remove the magnetic plug and see the metal shavings, isn't the magnet doing it's job and keeping those particles out of the bearings and so forth? I would put forth that the diff fluid, while it may be needing to be changed due to heat/age/wear and detergents decaying over time, the metal filings on the drain plug aren't a sign of the fluid needing to be changed, but merely a sign of the diff magnet doing it's job.
Maybe I'm misinterpreting what I've read but that's the impression I get.

That may be part of it but if I recall this thread, I think the stories of black stinky goo coming out of the diff is what prompted people to change it.
I did mine while I was putting on my F.I. exhaust just because it was easier with the exhaust off.

I originally posted this in another area but thought I'd park it where it would do someone some good or at least confirm my results of changing Diff fluid at 14,500 miles.

Changed my diff fluid today. Put in Mobile 1 75W90 GL-5 compatible http://shop.advanceautoparts.com/web...bil1_7070039-p . Typically, the magnetic drain plug was coated with iron/steel filings just like the other pics. I didn't jack it up just laid on my back and filled first with the bottle then with a large syringe my wife gave me (she's a nurse). I used just over 1.5 quarts. I filled until I saw it run out the fill hole and then let it drain for several minutes, then put the screw back in.
I got new washers for top and bottom plugs.
Fluid was like dark chocolate and markedly darker than what I put in, which was a clear yellow color.

Honestly there would be a tolerance level (X bits o meal of X length and X width) That said i have no clue what it is on the Z. I work on Apaches for a living and its generally a huge issue for chips on something like the transmission or a gearbox....but thats an aircraft. Even with small chips tho we drain and flush the component to ensure longer life.

My personal take on this tho is that if your getting large bits of metal on your pickup then something isnt right. Drain it, flush it, and put it down as one of your scheduled maintenance items. Just my :twocents:

Revised diff
 

Does anyone know if those fins have any fluid running through or is it just for diffusing heat? Please let me know. Thx.

There is NO fluid running thru the fins.
Yes, it's there to just diffuse heat. :tiphat:

See link to post below.

http://www.the370z.com/1967112-post97.html




.

Got inspired and changed mine today at 29,700. Just some thoughts on the process... Draining, no big deal. Easy to get to, filler first, drain plug next.

The oil looked good, just a little grime on the magnetic plug... Let it drain and had lunch. Put in some mobile one which has a pointy end that you clip off like a tube of caulking. Had some clear tubing laying around with 1/2 I.D. That just fit the end of the quart, so I cut about 8 inches and put it in the filler and squeezed the quart container and had most of the quart in within a minute. Rather than try to squeeze out the rest, switched to the second quart and got most of it in. I combined the leftover first quart into the second quart container and squeezed it in till it came back out, plunged it and done.
I purchased a crummy $7 pump but never used it. I'm sure i would have been wearing it if the clear tubing came loose but I guess I was lucky. So anyway it worked for me and was done in no time. http://img.tapatalk.com/d/13/10/24/esajareb.jpg

Thanks!

Doing this next weekend. Any reporting problems just jacking the rear up when doing this? I may just try to get under there with no jack seeing as I'm not lowered

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Use a ramp.

Same thing as jacking the rear up. But my main concern was about the car being tilted and wonder if anyone had any problems due to slighty overfilling it?

ramp is easier. and never heard of such issue.

Don't monkey around with it, just place the car on 4 jack stands and call it a day. On my stock, non lowered g37, I could not squeeze under it to change the diff or tranny fluid. Maybe if you're #120 you'll fit :)

Also, this way there's no risk of overfilling. You fill it til it starts to overflow, let it over flow, then put the plug back in. Don't over torque. It is aluminum. Snug is all you need.

Man you weren't kidding about the old fluid smell. God damn that is bad haha and the amount of.gunk I had on the drain plug. Absolutely gross. Really happy I did that today.

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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.

The write ups says 2 quarts. Is 2 quarts enough to fill it up and have some extra fluid, or should I order a 3rd quart just in case?

I will also do the transmission which requires 3 quarts and am wondering the same thing.

I dont want to have to spend money on extra fluid if I dont have to, this stuff is expensive...

The FSM says differential fluid volume is 3 US pt. That is only 1.5 US qt, so you will be fine with 2 :tup:

Yes order 2 for just the diff. I had a little left over. When it starts spilling out of the fill hole you're done.

To clarify, Z1 recommends an additional quart if you are removing the rear diff cover. They claim the actual volume is 2-1/4 quarts. But you can't drain all the fluid, so unless you remove the cover, you're fine with 2 quarts.

Yup, still have half a quart left from the 2 I started with. Felt great to clean all the nasty sludge and shavings off the drain plug. On another note, the drain/fill plug gasket didn't look to me like the copper crush type, they looked like steel or something else to me and mine looked perfect so I simply reused them and gonna keep an eye out for leaks, bone dry thus far.

And for this, my dealership wanted to charge me $130. :inoutroflpuke:

Nissan Part #11026-4N200

For the transmission they are called a gasket. For the differential, they are called a washer. Same part number.

I reused them once when the dealer sold me the wrong parts. I had no issues. But they aren't expensive, so I just bought like 20 of them last time I bought parts.

Yeah, I just foolishly didn't have them when I changed mine, no leaking thus far, just going to keep an eye on it and throw fresh ones on at the next change if there's no issues.

Is the Mobile 1 differential fluid comparable to the OEM in term of quality?

Any gear oil with the proper weight/viscosity should be fine. Most people here will recommend Redline. I use Mobil 1 engine oil, but I use Redline gear oils.