I have a 08 350z 6speed with a little over 40k miles on it now I have had for about 2 months and from what I been reading the transmission is common to be notchy or crunchy nut when I start to drive it the transmission for the most part is fairy smooth but the more I drive it the worse it gets I don't know if I am being paranoid or what i have read to use redline or amsoil or royal purple what's the best solution I think it should shift smooth for how new it is

 

I have made this recommendation in over 100 threads and I will continue to. Switching to Redline MT-85 is IMO the best thing you can do for your Z's tranny. I will never switch to anything else.

Since you are around 40k and will be changing the fluid, I recommend also changing the diff fluid since you are already under there. I used Redline fluid for that as well and no complaints.

 

I second the recommendation for Redline MT85 and use it in both my street and race Zs. The '07-08 Z33s have the latest version tranny and are not usually "notchy or crunchy" unless the driver is being ham handed with it.

 

So how many quarts do I need and do you run MT-85 in the diff as well

 

You'll need to purchase three quarts of MT85, although most gearbox cases take slightly less. The diff requires a completely different lubricant with high-pressure additives that would EAT the soft metals in your tranny. Also takes a different viscosity, so read your owner manual.

 

Mobil 1 full synthetic trans fluid and gear lube is premium stuff too and you are fine to use it for the life of your car including engine oil. I've got the Redline MT85 in my trans and RL clutch fluid too due to clutch/flywheel change (came with kit) and I'd recommend it also, but have always used Mobile 1 fs in engine, trans, diff. and have no reason not to continue. *Diff. lube stinks!

* I think that you get 4 qts. of trans fluid and fill until it begins to drip out of fill hole; don't think it can take the full 4 qts. Differential lube needs 2 qts, but it won't take the full 2 qts. either, just go until it has a steady drip out of fill hole; car is level of course, the qts. aren't cheap.

 

Why do some people hate the redline mt-85 and say that it makes it worse and to just refill with oem and it makes it better and that just from factory that it's overfiller and that's the problem

 

I've never heard that about Redline; only good reports that I've seen. OEM fluids would be just fine for your car. It's hard to overfill the trans or diff because when it reaches full there is no doubt as it's running out.

 

When i bought my Z (at 60K Km's, around 40K miles) i changed all oils on the car and used Valvoline Synpower gear oil GL-4, 75W80 for the tranny. (for the diff same brand but then GL-5 80W90)

Don't know what oil came out, guess OEM, but it made a big difference for smoothness.
Only when the oil is cold it's a bit stiff in all gears but as soon as you start driving that disappears.
Here in europe the redline oil is hard to find and i rather stick to some lubricant that is easy available.
But for some i can also recommend the Valvoline oils.

 

I'm glad I found this thread. I too found the thread on this site where people are hatin' on the Redline (saying the Nissan MTF is much smoother then Redline, Redline is too thin, and the rough shifting is often caused from overfilling the transmission fluid): https://my350z.com/forum/maintenance...-review-2.html
I was just about to buy Redline MT-85 on Amazon when I found that link, so then I deleted the Redline from my cart and put in the Nissan MTF (which surprisingly is more expensive than the Redline). However since I found this thread with dkmura recommending the Redline, I guess I will go with that after-all.
I have 50k on my '07 and probably still have the original transmission fluid (bought it @ 30k). I felt like it was rough on the track this weekend when shifting from 3 to 2, but it was likely due in part to my mediocre heel-toe skills.

 

Sounds good, you should notice a good improvement with the trans feel/shifting since your's is due for new fluid. Good luck with it and post up any results, etc.

 

So I finally got a chance to go on track with fresh Redline fluids in my HR (MT-85 for transmission and 75w90 for differential) and every shift was very smooth. I am extremely pleased, since I was thinking I might have a transmission issue. I will soon change these two fluids in my daily driver DE as well and see if it helps my notchy 1st and 2nd gears. Thank you to everyone for sharing their knowledge and experience.