If anyone hasn't changed the differential fluid yet...
 

stop thinking and do it.

I recently swapped out the stock 6MT fluid for Redline MT-90 and the stock Diff fluid for Redline 75W-90.

The tranny fluid that came out didn't look so bad, I'm at 11k miles right now.

However, the DIFF FLUID that came out was nasty, full of SLUDGE, and metal shavings.

See this thread, my diff fluid looked just as bad:
https://my350z.com/forum/showthread....erential+fluid

It was the most dramatic maintenance I've ever done to a car in terms of how the car feels and drives.

Before the fluid change, when the car was cold, the clutch used to have a hell of a time getting the car to move. I would have to rev up to 2.5k rpm just to keep the clutch from vibrating violently.

I used to think the stock clutch just SUCKED, but after doing the diff fluid I realize that the problem was actually ROLLING RESISTANCE. Extreme rolling resistance while cold. Best part of all, I actually like my OEM clutch again!! I was very close to switching to JWT.

Now, I can make the car move effortlessly with about 1200RPM, with no vibration. The car feels like it just purrrrs now ;)

The trans fluid made a slight difference too, but nothing like the diff fluid. Shifting is still fairly notchy, and I can feel the dog teeth engaging just like before. Considering I only have 11k miles, the diff fluid is something everyone should do. I think I will change the diff fluid again at 30k just to see how the fluid has held up.

how much fluid was needed for the diff?

Also, why'd you go with MT90 over something a little thicker? I'm personally going to go with a thicker fluid for my tranny, especially for the motor build.

Diff is almost 2 quarts. I just kept pumping fluid in until it leaked out. The car must be level for this reason.


MT-90 is the thicker grade of the redline MT oils at 75W-90. MTL is thinner at 70W-80. Other members have suggested mixing 50/50 MT-90 and MTL. I opted to go for all MT-90. Maybe if you're running much more power, a heavier oil is appropriate but I can't say because I don't know.

They do offer thicker stuff like 75W-140 but it's GL-5 rated so it's no good for the tranny. Maybe amsoil makes a good 75W-140 GL-4 tranny oil if you're interested.

Agreed. When I changed my Diff out I changed the oil. You have to use rag to get the sludge and shavings off the plug, it looks like a big grey turd stuck on there. The oil drain took a whole 15 minutes in 90 degree weather.

I put 1.8 quarts of Full Synthetic Valvaline in mine, runs GREAT!

actually, redline's Shockproof Heavy is significantly thicker than MT90. I used MT90 for one session in my old turbo sentra, then swapped to heavy shockproof. While the MT90 was fine, the shockproof significantly smoothed shifts. While it's a lot thicker, it probably increased friction losses, but the added protection was great, as hot as everything gets in there.

what did you use to pump the fluid into the diff with?

Not the best tool ever, but it got the job done. It was nice that I didn't have to be under the car while pumping.

http://store.summitracing.com/partde...5&autoview=sku

About the heavy shockproof: I don't know if I would use it in my trans. Simply because I can't seem to find whether it's GL-5 or GL-4 rated.

Is it something you can do if you have never done it before?

I did it by myself and have never done it before.

Everything you need is listed in this thread.
https://my350z.com/forum/engine-drivetrain-and-forced-induction-diy/131098-changing-the-differential-transmission-oil.html

You basically just need either a hefty 10mm allen wrench or a hex wrench attachment for your ratchet. I was able to get the plugs off with the allen wrench, but they are on there pretty tight.

Nice info Mike I should do mine at 100k also.........

I'm sure you meant 10K :)

actually no I have about 103k on my Z

it's not GL-5, that's for sure. the heavy-duty turbo b13 sentra guys have been using heavy shockproof for a while. It pours like honey, but once it warms up, it's like butter. Even cold it's not brutal. I used it in 2 sentras for years and loved it. Good stuff.

Yep... Ed I don't know if you remember a while ago I made a thread asking about my clutch causing violent vibrations. This cured the problem totally :D

https://my350z.com/forum/showthread....ghlight=clutch

I would recommend definately redline MT90 or amsoil since they claim to have specific additives for syncro protection and smoother shifting. I'm also using redline MT but 50/50 mix only because redlines reps. told me to. I was very sceptical about that at first but still no probs. Good stuff.

exactly how difficult was this install can we accomplish this with average mechanical skills............can you help a rican out :o

Changing my tranny and diff fluids made for a lot nicer driving experience. I used Royal Purple though.

I need this done badily as I have never done this to my Z

I can show you how if you dont know once I get to Cali, just pay me in beer LOL

I can do better if you help a.... 40 Ounce of Old English

Old E

FTW!!!!!