The gear oil viscosity scale is different, so 5W30 is actually pretty close to 75W90. They probably did this on purpose to prevent people from trying to stick engine oil in their transmission and vice versa. I've had good results with Redline MT-85.

so, 5w30 is actually 75w90??

According to the specs on the Amsoil site, they were quite different in viscosity.

Red Line MT-85 Manual Transmission Fluid 1 Quart - 370Z - performance parts

The viscosities are essentially the same yes, but the formulation and additives are a little different. Gear oil has shock additives to help cushion the gears as they come together and additives to help the synchro's grip more easily (limit the slipperiness of the fluid).

also confirming that we need 4 quarts for our 370z?

No, the MT only needs 2.5 quarts (2.83 L).

oh ok. The link I gave about stated we needed 4 quarts. Weird.

If you were doing a flush maybe, but 2 was plenty when I did mine. Just make sure the car is nice and level so that you get an accurate fill.

My 06 Z had the world's notchiest transmission ever. After 3K miles, I switched to Redline MT-90 (if memory serves) and couldn't believe the difference. Going with MT-85 when I do my next oil change (I mean hey, I'll be under there anyway, right?) :D

What does a typical tranny fluid change run? Is it as quick and simple as a standard oil change on our cars?

Edit: NM. Pretty damn easy on this car. Drain plug underneath. Refill plug on the side of the tranny.

Spearfish25 has an excellent DIY: http://www.the370z.com/diy-section-d...il-change.html

It's easier, IMO, than a oil change, with the exception that you'll need a pump for the new fluid. No idea what the cost would be, sorry, but if you provided the oil I can't imagine it being too much at all.

whats everybody changing their tranny oil at???

ALSO, anybody forced to change their clutch yet? Trying to figure out some future planning lol

Did ALL the fluids with synthetics (except brakes and clutch) at 5000kms. The diff was especially gross from the factory setup. Tranny looked like new, but wanted better.

I changed my transmission fluid at about 7000 miles, the fluid still looked brand new. The diff on the other hand was a nasty smelly mess.