Lower viscosity definitely means "thinner"

After looking at this, I think MT 90 seems like a decent choice afterall. By the way 85F is definitely very COLD for your trans, even if it feels warm to you


Anyway, MT90 is still pretty notchy while cold, but it's no worse than the stock oil. It does feel better when crunching the gears when fully warm. This is all subjective... but I can tell you I have no complaints about mt90

 

And:

Amsoil MTG 75w90 GL-4
K. Viscosity@100C: 14.7 cSt
K. Viscosity@40C: 84.5 cSt
Pour Point: -47 F
Specific Gravity: N/A
Viscosity Index: N/A

What is the Nissan fluid specs ?

 

Spent a little time looking yesterday and couldn't find squat.

Nissan/Infiniti HQ Multi 75w85 (part number 999MP-MTF00P)

 

My guess is nissan MTF is right in between MTL and MT-90 in terms of every spec.

 

Great thread guys... I used this as reference a while back.

I switched to Redline in May, so far no complaints. When shifting, its more of a gliding motion vs a notchy vibrating motion. I never shift hard or get on it when first driving, otherwise you're just asking for a gear grind!

This is what I used.
Redline MTL / MT-90... 50/50 mix
Redline 75W90 Gear Oil w/o friction additive

Zquicksilver

 

You'll really find out when it gets a bit colder in November/early December.
I have the Amsoil and it's hard to shift into 1st or 2nd for the first mile or so.

 

I'm betting the stock fluid is actually closer in viscosity to Redline MTL 70w80. The SF MTL-P I have in there already looks like a 50/50 mix of the two Redline products. Anyone running just MTL 70w80?

The owner of SF was cool and refunded my purchase price stating everyone's experience seems to differ as each transmission reacts differently to each fluid. ...he even suggested trying Redline and RP as he knows others have had success with them.

 

First time changing the diff fluid, I am assuming the fill hole and drain hole are in different spots? Anyone care to point out where?

 

Look under your car. It will be obvious. Drain is under the diff while fill is higher up facing the rear.

 

Changed my diff. fluid today. I used Mobil Synthetic. It's easy and I didn't even need to lift the car. If you lie on your back between the tail pipes and scoot in a little you can access both the drain and fill plugs. As far as the washers are concerned, just inspect them and make sure they aren't gouged or bent in any manner prior to reinstallation.

 

I'm going to change my diff fluid on fri. I think I am going to try RP-max gear 75-90. If anyone has opinions on the rp throw em up.

 

I swapped out my differential fluid today on my lowered 03 G35 sedan with 41K miles. I was actually to squeeze myself under the car do the work....in an odd, but effective manner. I did forget how nasty gear oil is though. Breaking loose the filler/drain bolts was pretty easy even after 3 years of salty Midwest winters. The fluid that came out looked fine and I had made sure to drive around for 5 minutes to warm it up. The drain bolt magnet seemed to be more covered in a snot-like goo than metal fillings. Definitely use a suction gun though. It's messy enough the gun. I can only imagine the mess without it. Next up is my wife's 98 Legacy GT wagon with two differentials.

 

So, if I am changing both the Tranny fluid and Diff. fluid, I need 4 crush washers, correct? And the pictures in the original post are pics of the diff only?

Also, is there any benefit of going synthetic over the regular stuff? I am asking because I can get the Nissan Diff/Tranny oil at cost and I will be changing the two fluids every 15k miles from now on. This is the first time I will be changing them in 36+months...eek.

 

It seems like everyone in LA county is either closed on Saturday or they don't have everything that I need in stock

Anyways, I picked up 3 quarts of Redline MT-90 and 1 quart of Redline MTL because that was all that I could find today. I wanted to get 4 quarts of MT-90 but hopefully this should be fine. I'll let you guys know in a couple weeks how it feels.

 

I just did mine. The hardest part was getting the allen wrench to turn the hex because of lack of space and the bolt has froze. I suggest a mallet and a wrench rig or breaker bar because it is extremely tight. I used Motul 300 and Gear oil from Performance Nissan. I can hear the exhaust much clearer as someone mentioned and the Z will roll without hitting the gas when releasing the clutch.

I did it at 40k miles btw.

 

i did mine yesterday with RP GearMax. every gear seems to run smoother except for the second gear. it's kinda hard to shift into second gear when its cold. i know some of you guys have experienced the problem before changing your fluid but i just started to experience the problem after i changed the fluid? is it normal?

 

I have heard people having problems with Royal Purple. Some guy over at G35driver.com changed his tranny oil with Royal Purple and he noticed his gears grinding after the change...it got worse over time as well. He changed it back to OEM fluids and said it ran much smoother. Just so you know.

 

I used a different synthetic, but had the same experience. The seller was nice enough to refund my money as he stated it was specifically engineered to improve cold performance. He and many others have stated, there is no one oil that will work for all trannies (even the same make). Each responds different, so the only way to find the magic recipe is trial and error.

I still haven't put the stock fluid back in b/c I'm contemplating other options, Amsoil, Motul, etc.

 

well actually its not that bad after all.. it's so hard to downshift to second gear only when its cold (i have to really force it hard to go into 2nd). its another story after it gets warm up a little.

 

Try double-clutching until it warms up...seems to help me most of the time.