So I changed the manual transmission fluid in my 05 42k coupe with 0 shifting issues cause i figured it was about time.

I changed to synthetic royal purple 75-90 and filled util started coming out. 3 1/8 quarts even checked to make sure this was used from containers, no spilling whatsover. Now it shifts hard between 1st and 2nd.

How is this possible???

 

^^ Its usually ok to use other oils in the car but for some reason I have read that in the transmissions we should use oem. I believe RP and other synthetics say that they are both GL-4 and GL-5 compatible. I have always had a problem with this since the manual gear box specifically calls for a Gl-4. For this reason I stay Gl-4 specific with the gear box, since I dont know what additives are present in the synthetics that are both Gl-4/Gl-5 compatible. The additives in GL-5 oils can eat away at the brass synchronizers, and should never be used in a transmission.

Oem gear oil is usually the safest for our manual transmissions. Couple guys over on my350 have had this same problem. They switch to anything other than oem and the shifting feels worse. Maybe swap back out to the oem gl-4 oil and see how that goes.

 

i WILL try that thanks. I am just totally blown away that it was immediate. I mean literally right after I changed it I drove down the road and it was suddenly hard shifting between 1st and 2nd which I never experienced before.......

thanks again for the info

 

using a 90W oil can mess with the syncros. use a 90MTL and 80MT mix 2 quarts each. check out niccoclub.com it has a diy.

 

Actually according to the Infiniti manual 90w is in recommended spec.

"Genuine Nissan Manual Transmission fluid(MTF) HQ Multi 75W-85 or API GL-4, Viscosity
SAE 75W-85 or 75W-90" .

Thanks for the idea but I think I will go back with the oem.

 

I'm about to change my tranny fluids with Amsoil MTF fluid. Has there been any reported problems with using Amsoil? I was told that OEM fluid was like $20 or so a quart. :-\

 

I've never heard of anyone having problems with the Royal Purple.

I know several that have changed it and went with RP also.

 

Well all I can do is reiterate that I never ever had any glitch, catch , hard shifting whatsoever with oem. Immediately after change to royal purple hard shifts between 1 and 2nd.

OEM is about 10$ per quart......... I am going to change back with post if there is any change.............

 

I would do a search on here before you do that. Many people that had issues with transmission swapped to different fluid. Not saying you should keep RP, but look at the AMSoil and other stuff people have gone with that have been better. If you're gonna spend $10/qt you might as well get a better fluid.

 

I've heard of few Royal Purple complaints, it's Amsoil and OEM that are issue free.

https://g35driver.com/forums/reviews...t-so-good.html
https://g35driver.com/forums/tsb-tec...when-cold.html

If i'm not mistaken, RP and Redline were only good in warmer climates. The OP might be getting issues with Royal Purple in the chilly mornings of upstate NY.

 

Yes, i can verify that I put Redline MT90 in mine and it started shifting harder, I just replaced it with the standard grade OEM oil, 75W90 I think. Now it shifts like butter. Synthetic isn't always the best.

 

Not so!
Been there done that.
I had the same trouble with Amsoil.

YES.
I had the same problem.
Switched back to OE and it was good again.

 

Well I have done some research and I have found complaints about every synthetic transmission fluid and None for oem...... So I think I will go back to OEM.

"Amsoil and OEM that are issue free" sounds like an amsoil salesman! LOL. If you have had luck with this I am happy for you, but there are complaints out there regarding amsoil as well.

 

^^ ya man. Stick with the oem. Our gearboxes are real sensitive I guess

 

I'm no salesman...lol, I guess I'm just one of the lucky ones with amsoil. Then again, people unknowingly buy the wrong weight/spec sometimes. If i'm not mistaken, amsoil has several ones that they claim would work just fine with the G. My guess is, there's only that "one" kind that works and not several ones.