Wanted to warn everybody that if you change your coupe manual transmission fluid, stick to the Nissan spec (MTF HQ Multi 75w-85).
I wanted to see if I can take some knochiness out of the shifting action by trying a different fluid, Shell Spirax synthetic to be exact but it made things worse.
It was about 50 F the next morning after I changed the fluid, as soon as I got out of my driveway and try to put it in 1st it would not go in, I had to double clutch a few times to get it in. It happened to me a few times after that. It even happened in reverse. It was also sometimes slightly harder to shift into certain gears.
I have read that some people on the forums had similar problems with Mobil and Amsoil but never expected it would happen with Spirax, even with the good forum reviews about this gear oil.
So I’m writing this to save you guys the headache, stick with the Nissan Spec. It seems that our Manual trans is very finicky and it only likes Nissan HQ Multi.
I have since changed the fluid back to the HQ Multi and everything is ok. By the way this oil is kind of expensive at $10-12 a quart, but if you shop around you can find it at a discount $8.50 a quart. This cannot be ordered online, as some merchants won’t ship hazardous material, so you have to shop locally. Our trans takes 3.25 quarts, so 4 quarts are needed.

 

Good looking out with the warning. I had the similar idea to change the fluid, but I asked the dealer first, and one of the mechanics said that Infiniti uses synthetic manual tranny fluid, and that it is good until 30k miles, and it's as good as it gets. Your story just reassured me. Thanks again.

 

I'm switching to Redline MT-90 next year. Supposedly it's the best thing out there for transmissions of all sorts.

 

hm im running spirax on both trans and diff and its been working great.. and yeah it is a bit pricey

 

Any car on cold day start-ups acts notchy....let it warm up man...once jucies get flowin it'll be alright.

 

i switched to redline about 2-3 months ago. i got it specifically for the colder weather. last winter it took about 5 minutes of driving for me to shift smoothly into first... i was basically running off a stop in second during that time. i thought the redline would make a big difference but guess what, it didn't. this passed weekend i drove 2 hours north to visit my buddy and it was considerably colder with a lot of snow on the ground. i had to park my car overnight outside for a couple days (as opposed to my garage)... and when i drove off back home after the weekend i had the EXACT same problems that i had last winter. if your thinking of switching... i say save your money on something else, because i don't see any benefits in the redline synthetic at all. only pro is that i didn't notice any problems with the redline either. my tranny operated as normal.

 

When everyone first started talking about switching their manual transmission fluids to synthetics, I was very interested in what the actual results were. There were tons of posts talking about "Try Redline" and touting how good the white paper specs were for the Shell Spirax. However, it looks like the actual performance is really lacking compared to the stock Nissan fluid.

I pretty much expected this, that's why I never bothered changing. I had a terrible experience with thin synthetic fluid on my previous car. Basically, switching to a thin synthetic fluid (BG Syncroshift) made shifting much smoother. However, it also resulted in damage to my transmission. After 2 years of use, when I switched the stock fluid back in, it would no longer shift without grinding hard. Therefore, I had to keep using BG Syncroshift which further damaged the tranny. A downward spiral...

 

I agree. I know many are still in denial or it does make a difference for them, but I realized on my previous car, that when you get a pretty good car, most aftermarket performance or maintenance items are just not doing anything better than OEM for performance.

 

Yes, once it warmed up it was ok and did not have problems when putting it in gear. But I never had this problem with the Nissan spec oil. To me it was like taking a step back.
I also thought if any problems occurred with this oil, Nissan would not honor the warranty, as a few people on the 350Z and this board have experienced.