i have an 07 g35 coupe and have been noticing more and more grinding of the gears especially 5th gear when the car is cold....does this mean the clutch fluid needs to be changed? the car has 50,000 miles and my friend recently installed an exedy clutch and flywheel 4000 miles ago, but the grinding was there before that. The fluid didnt look too dirty so we decided to leave it. Would new fluid help the gears not grind (and yes i know how to drive manual trans, this is a mechanical issue, not user error)

 

New fluid may help depending on whats already in there. Most cars will shift a lot better in the warmer months when the fluid is a lot warmer, but in the winter the fluid gets cold everything stiffens up

 

also does anyone have any recommendations on a common type of fluid to use? something i can buy at auto zone or pep boys or something

 

I used the redline MT-85. You can go to redline's website to find a local dealer

 

Clutch fluid should have nothing to do with gear grinding, as long as you don't have any trapped air bubbles in the system.

A more likely culprit would be the transmission gear oil being low, or of the improper weight/viscosity. Our transmissions are notoriously finicky about the weight of gear oil used in them, and the recommended weight/viscosity of our oil is not a standard rating that you can just pick up in any old automotive parts store. What I did when I changed mine, was go to Nissan and buy a few quarts of their Manual Tranny gear oil, rather than buying it from Infiniti. The stuff you buy at Infiniti is exactly the same as the Nissan stuff, but costs like 25% more from Infiniti.

Aside from the Tranny fluid though, I use all aftermarket brand lubricants/fluids in my car.... Amsoil Brake Fluid, Clutch Fluid, and Differential Gear Oil, and German Castrol motor oil.

 

I just want to point out that Redline MT-85 is not clutch fluid.. it's gear oil. Basically it's transmission fluid for a manual transmission, whereas clutch fluid goes in the little reservoir in the engine bay and is used to operate the hydraulic clutch.

 

I dont think any of the transmission fluid, clutch fluid or diff fluid has been replaced since i got the car and im about to hit 50000 miles. how often am i supposed to change all of those...sorry im always really busy with work and lost my owners manual. I know i should take better care of this car and im going to end up paying for it in the long run

 

Infiniti recommends changing the MT gear oil every 30K miles. You won't likely be doing any damage by not changing it for 50K though. It's not like motor oil or Auto Tranny fluid where the fluid picks up contaminants and rapidly loses its ability to lubricate, or is subjected to immense pressure or heat. The MT gear oil is simply soaking the gears in the transmission and keeping everything lubricated. I believe the drain plug is magnetic, so it should pick up any pieces of metal that might get sheared off of the transmission over time, that way they don't continually get pushed around inside the transmission along with the fluid.

If I were you though, I'd get on that and change it out ASAP. It's very easy to change yourself, as long as you are able to get your car up a little higher off the ground a little bit by using ramps and/or jackstands. Make sure you use the Nissan MT fluid when you change it, and if you have a mechanic do it, buy your own fluid from Nissan and bring it in to have your mechanic put it in for you.

About your grinding transmission... does it do it in all gears and all situations, or just in a specific gear or situation? Have you tried double-clutching and rev matching on your shifts to see if that helps alleviate the grinding? If you double-clutch and do perfect rev-matches, this would mostly negate the transmission gear syncrhos from the equation and maybe give you a better idea of what the problem is.

 

Just be sure you buy a fluid pump if you do it yourself. If not, you'll need a long piece of hose

 

Um it only happens when cold i havent tried double clutching. if there was an issue with the transmission like the synchros or something would it be covered by the drivetran warranty? i shouldnt have to double clutch this car and i bet the stealership will try to charge me a diagnostic fee and then say its not covered by warranty. I have already had the dealership try to jerk me around on warranty repairs because i look young and they think they can take advantage of me. i am going to have all of the fluids replaced and if it persists im going to the dealership. Can they tell me they wont fix the griding issue since i replaced the clutch with an OEM exedy clutch even if it is not the cause of the problem?

 

If your car is an '07, then it should normally be covered under the powertrain warranty unless you are over the millage limit for the factory powertrain warranty or if they try to claim that something got messed up as a result of the new clutch/flywheel. I think the factory powertrain warranty is 6 years or 70K miles. However, seeing that the scheduled maintenance interval calls for transmission fluid changes every 30K miles, and you're at 50K now on the original fluid, Infiniti could very easily deny responsibility for honoring the transmission warranty on grounds of neglecting scheduled maintenance.

If it only does it when it's cold, it makes me think that it has something to do with your tranny fluid. Definitely start out with some fresh new gear oil in the tranny, since that's the simplest, cheapest route to start, plus you're already far overdue for that maintenance item anyways.