Sorry, tried doing a search but it's still down. I'm changing my transmission and differential fluids. I'm considering using Mobil 1 75w-80 for the diff, (although I heard good things about Lubrication Engineers LE607 90w gear oil, I don't know where to get it), what kind of tranny fluid are you using? I went to the local Nissan dealer and asked for some Nissan MTF, but he doesn't know what i'm talking about. Thanks for your time and help.

 

These transmissions use a special weight of oil 75w/85. You will find that it is only available from dealers and Nissan will void your warranty if you use a different weight of oil. The factory oil is synthetic and very thin. This oil also doesn't have sulfers and extreme presure attitives (EP), so any oil that is EP rated is very bad for it. Check with another dealer that knows what they are talking about, since all the newer Nissans are suppose to use this style oil in there transmissions (if they are manuals).

 

thanks. i did some more searching and i was able to find the part # for the tranny fluid. its 999MP-MTF00P. i'm going back on monday.

 

Hey Johnlotusboy --
Where'd you hear that the Nissan MTF is synthetic? I was sure it was mineral base oil, since the bottle makes no mention of its origin. It is pretty expensive, though...
Mika

 

Redlined since 03 - not a slipage or grind since.

 

The manual says that 75W90 is acceptable for MT fluid. Royal Purple's MaxGear meets these specs. Anyone try using this instead? Any reason not to?

Thanks,
JasZ

 

I used Royal Purple on my previous Z and it made the gear very sticky and made the grind worse. Also Royal Purple is GL5 and You need GL4. Try Redline 70-80w which is synth but its GL4. I used it on the my previous Z after trying Royal Purple and it works great. For some reason, the Z requires real thin MT Fluid.

 

Where does the manual say that? I've only seen 75w85 GL-4 listed.

On my last transmission, I did try Royal Purple Max Gear 75w 90. It did smooth out the shifting a bit compared to Redline MT90 (also 75w90). Ultimately, though, the transmission was plain notchy, so I had it replaced. the new one is notchy, to, for what it's worth...

Mika

 

It says that here. Also, Royal Purple's Max Gear and Redline's MT-90 both claim that their additives are not corrosive. I am a bit confused now about what is appropriate. The Redline MT-90 is GL-4 though.

 

mwaller,

Thanks for the input. I was really wanting a comparison of the MT-90 vs. the MaxGear.

 

Where did you find that image? My owner's manual only says 75w85.... is this in the 2004 owner's manual?
Mika

 

I don't think that Nissan can void your warranty if you use a weight they have listed in their manual.

 

Yep. '04 owerners manual online. Also in my printed manual

 

Royal Purple specifically says that MaxGear is safe for GL-4 applications and Redline says that MT-90 is GL-4.

 

If it's true that Nissan blesses the use of 75w 90, I may try Royal Purple MaxGear 75w90 again.
With my new transmission, I wanted to be sure to only use what Nissan recommends, so I just replaced the original fill with Nissan's own MTF (to flush out break-in debris).
Knowing that 75w90 is ok to use, I think I'll go back to Royal Purple to see if it helps with the cold shifting roughness I feel.
Mika

 

Yeah. I was thinking about doing that too. The only thing is that GL-5 vs. GL-4 issue with the Royal Purple. But since you tried both and thought the Purple was better, I think I may do the same.

I am also considering using the Royal Purple SAE 90 MaxGear fluid for my differential. I want to get everything over to synthetic as soon as I can. Got any input on the diff. fluid?

Thanks,
JasZ

 

I've had Redline 75w90 in my diff. since 5K miles. At 30K miles, I drained and replaced it with Redline again. It was a bit murky at 30K, which is to be expected. I didn't run any oil analysis, so I have no evidence to suport its claims of superiority in reducing wear, nor anything to compare it to. However, everything I have read has indicated that redline gear oils are among the best in the business. Redline uses exclusively poly ester-base stock (regarded as superior to cheaper and more common PAO base stock) I've not read anything to suggest that Royal Purple makes an inforior productl, but I have absolutely no idea what they put in the bottle... they don't tell you. I'm sure it's good. But their website is more full of marketing puffery, which makes me wonder about their product. Judging by the way they advertise it, it seems "too good to be true," if you know what I mean. Their marketing department has gone so far as to color their oils purple, which serves no functional purpose. If anything, it may harm the performance of the oil. These are just my impressions; take them for what they cost you :-)
Regardless, Redline didn't work as well in my transmission. Go figure.
Mika

 

if anyone is going to use Redline, use 70-80w (GL4). The Z tranny fluid needs to be thin.

 

I recall earlier there being some discussion about how the redline MTL caused premature bearing wear in 300ZX transmissions... I have no personal knowledge of this, but it was reported on the forums...
Redline recommends a 50:50 mixture of MTL and MT90 to give a viscosity very close to 75w85. Personally, if using redline, I'd chose plain MT-90 for its higher film strength.
Mika

 

MT-90 is the correct weight for the transmission according to '04 manual.

BTW I just had my engine oil changed to Royal Purple and my MT fluid changed to RP Max-Gear 75W90.

I'll post if my car blows up. -unless I'm dead.