Bone stock 08 6MT with 6000 miles. I switched out the tranny fluid in my 04 Lexus IS300 a few years ago for Red Line and decided to try it on the G37 too. Did it yesterday, as well as the differential. Not a huge change but well worth it. I used about 3.5 qts total of Red Line MTL and MT 90, split evenly between the two in order to get the right weight. Before the change I had a somewhat noisy throw out bearing or pilot bearing (not sure which) but other than that no problems at all. With the new fluid in there, the effort to shift has not decreased really, but it does shift more quickly, and definitely more decisively, much more of a click click, one gear to the next. It no longer feels as if I'm shifting through the resistance of the gear oil...not that it was bad before, but this is better, much more definitive shifts.
It is an easy swap to make, both the drain and fill holes for both trans and diff are real easy to get to once the car is jacked up level. Note that you need a 10mm allen wrench or Hex key to get the fill/drain plugs off. This is a somewhat large size wrench and may not be in your standard set. Best to check before you get it up on jacks. Rear diff uses 75W-90 and about 1.5 qts.
Oh, one other thing---the crush washers cost $4+ each at the dealer. Thats just insulting, not a lot of money in total but its the principle of the thing. So I said I'll pass and hope the existing ones reseal ok. Retorque'd to around 25 ft pds...

 

Good job! I plan on changing mine but if the throw out bearing still remains noisy I might not bother. Mine shifts ok. All Nissans have that tough shifting and clunky tranny.

 

sounds like this would be worth it to do. about how much was the cost of the replacement fluid and where did you buy from? I have not found any pics of where to find the drain and filler locations on the tranny, please post if you have some from when u did ur swap. Also I think I may have trouble getting underneath there because of my drop.

 

Red Line oils are 10-12$ per qt. You can buy straight off the Red Line website. Here is a URL that gives detailed steps to do this swap, as well as pics of the hole locations.

http://www.350z-tech.com/zwiki/Rear_...id_Replacement

But the drain and filler locations are painfully obvious once you get under there.
You will have to jack the car up to get access with or without drop.

 

There is a thread on this already in the stickies of the DIY forum. You might want to post your thought there.

Welcome to the forum.

 

Throwout bearings are dry lubed, so a fluid change isn't going to help.

 

do you guys like redline better than amsoil or royal purple tranny oil?

 

i do not have personal experience comparing them. But I'm skeptical there is much difference in this application.