I ran Motul Gear 300 and PA90 in the rear diff in my STi and it was great. I've been thinking of changing to Amsoil... but I've always had good experience with Motul stuff.

I just ordered the redline 85 for the man trans since I just hit over 30k. I was wondering and never thought about the rear diff. When should that be changed and what's the concensus on what is the best to use??

Has anyone used Mobil 1 syntetic gear oils on their diff and or Manual trans? If so any comments (good or bad) thanks.

Is it true the AT transmission fluid never needs replacing according to Nissan? Also, what is the maintenance schedule for the diff. oil, or is that a "lifetime" oil too?

Thanks...

I think that depends mostly on how you drive. I would flush the AT fluid and replace somewhere between 60k and 100k depending, the flush technique is described in the service manual. I would only refill with Nissan ATF at this point. You need 2x the fluid for the flush.

For the rear-end, the viscous unit is sealed so you can only really change the fluid for the sake of the pinion and drive gears. It's not a bad idea to change it once after an extended break in, 5-10k, there is a fair bit of metallic debris on the drain magnet at this interval.

So the tranny fluid and rear diff doesn't have to be changed until 60?-100k miles? I would go Royal Purple just because they say I'll gain some horses and I saw it on Gearz and the guy gained like 10hp + on his dyno. Is there a how to on the tranny and diff fluid changes with pics???

The Nissan recommended maintenance schedule is as follows:

Oil and filter - every 3750 miles
Diff oil - every 30,000 miles
ATF fluid - every 30,000 miles
MT fluid - every 30,000 miles
Coolant flush - every 30,000 miles
Replace drive belts - every 30,000 miles
Spark plugs - 105,000 miles

Obviously you have to use some common sense. If you drive your car hard constantly then you are going to have to shorten the intervals especially the oils. If you drive like an old lady with 90% highway then you can double the intervals (except spark plugs), and according to Nissan not have to change the fluid in the AT at all.

I can't recommend Royal Purple in the transmission and diff, yes it has shown to increase power delivery by a small amount but it has also shown to increase wear at the same time. It is popular with racers as they don't care about wear, most of their parts fail due to abuse before wear is even an issue. Just remember that what you saw on TV was probably paid to be there.

Basically a repost but different people look at different threads so I wanted to throw it out there.

We have been using Redline for some time at the shop and the fluids we use for the following applications are....
We use the normal 75W90 for the differential. You can find it on our site HERE.
We have recently begun using Redline's MT-85 for transmission fluid. Redline specifically lists this fluid for use in the 370Z. You can see it on their site HERE. I really appreciate a customer and forum member for pointing this fluid out to us. The MT-85 fluid can be found on our site HERE.

Finally you can find the metal washers for the drain plugs on our site HERE.


This is what we have found works well in the majority of 370Z applications.

Bringing the thread back! Just order Redline MT85 and 75w90 diff fluid from Z1. Going to use Motul synthetic in the engine, I've been using Motul 300v Power Racing for the past 2 oil changes and when teamed up with an oil cooler its been great.