Manual transmission whine?

2011 INFINITI G37
75,000 MILES • 3.7L • V6 • 2WD • MANUAL
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BRANDON B
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I bought my car a few months ago with a blown head gasket (it flooded cylinder 6 with coolant which caused bent valves etc.). I had the engine replaced with a used one and at the same time replaced the clutch, concentric slave cylinder / release bearing assembly (upgraded to a HD version since stock are known to fail), clutch master cylinder and clutch lines. Now that I'm driving it, I've noticed the trans whines whenever the clutch is out, in gear or out of gear, same whine. Clutch in, no whine. It literally sounds like I have a supercharger wherever I go.
Aug 24, 2022 at 6:56 AM
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STRAILER
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It sounds like the transmission input shaft bearing has gone out, I would make sure the transmission fluid is full and clean. Here is how to check it:

Fluid Types

Manual Transmission Fluid

Genuine NISSAN Manual Transmission Fluid (MTF) HQ Multi 75W-85 or API GL-4, Viscosity SAE 75W-85

Capacities


Manual Transmission Gear Oil

Capacity .................... 6 pt (2.83L)


Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
Aug 24, 2022 at 8:51 AM
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BRANDON B
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Thank you for the reply, Ken. I actually just changed the manual transmission fluid yesterday with redline mt85 hoping that would solve the issue, but it did not.
Aug 24, 2022 at 9:20 AM
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STRAILER
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Yep, it sounds like the input shaft bearing is gone. the transmission will need to come out, let me know if you need help with the repair. check out the instructions below.
Aug 25, 2022 at 4:54 PM
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BRANDON B
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Thank you. Is there any other possible culprit that could be causing the sound? I'd hate to tear into it, replace that bearing, put it all back together and the whine will still be there. On an interesting side note, in my online searching I found multiple cases of people complaining about a whining noise coming from their 6mt in their G37. Many people said the dealership replaced the entire transmission at first under warranty, but the complaints became so frequent that Infiniti finally said the 6mt may produce a slight whine and that it's normal. I cannot verify any statements made by Infiniti; these are just things I've read on different forums posted over the years.
Aug 25, 2022 at 5:34 PM
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STRAILER
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I can tell if the noise is normal if you upload a video of the noise from inside the car. You can upload it here with your response.
Aug 26, 2022 at 12:23 PM
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BRANDON B
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First - second while still running cold. It gets a little quieter when warmed up, but not much.
Aug 28, 2022 at 11:21 PM
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STRAILER
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Thanks for the video, which doesn't sound that bad while driving, when the car is at a standstill and you push the clutch pedal in, it should go quiet, then let out the clutch to hear the noise. This is how you can judge how bad the bearing is getting. If the noise stays the same over the next 500 miles, you are good to go but if it changes and gets louder, I would pull the transmission and do the front input shaft bearing.
Aug 29, 2022 at 1:52 PM
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BRANDON B
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This is a cold start, clutch in, clutch out, repeat. I have put just under 1,500 miles on the car since replacing the engine, clutch etc. It has sounded the exact same since mile 1.
Aug 29, 2022 at 6:28 PM
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STRAILER
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Oh boy, that is loud. It might be that something is not allowing the transmission is sitting squarely against the engine like a heat shield or wiring clip etc., stuck in-between. Grab a flashlight and inspect the mating of the engine block and transmission bellhousing. If okay, I would pull the transmission and do the bearings. Thanks for the video. Let me know what you find.
Aug 30, 2022 at 1:07 PM
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BRANDON B
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Apologies for the delayed response. I found no obstructions between the bell housing and block. Given the fact that I have now put over 1,500 miles on the vehicle and the sound remaining the same since day 1, would you say the bearing needing to be replaced is imperative? I have no doubt it needs to be done; my holdup is the amount of money I've just spent to get it back on the road. I can't imagine the labor is going to be any less than the engine / clutch replacement. (I understand any response given is solely an opinion and part of a hypothetical best case / worst case scenario).
Sep 9, 2022 at 10:47 AM
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STRAILER
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The bearing does sound bad, if you plan to get a rebuilt transmission then you can continue to run the one you have but keep in mind the more you drive it the worse the damage you are doing to the remainder of the transmission.
Sep 10, 2022 at 2:15 PM
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BRANDON B
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So, basically, bearing failure is inevitable. Would you be able to give me an estimated labor cost on just having the bearing replaced? I can't find anything online that specific for a labor estimate. I know the bearing is about $70.00, I was told that the concentric slave cylinder / release bearing assembly must be replaced whenever the engine and trans are separated due to contamination (and flawed design), that was $360.00 (HD ver. w/ stainless, insulated lines), another OE clutch master cylinder $180.00 (require warrantying slave cylinder), new clutch and trans fluid ~ $120.00 (pricing is for my own visual reference), plus vehicle down time. It was only about 2 months ago that the initial repairs cost me about $6.5k, hence why I'm reluctant to get the bearing done immediately.
Sep 10, 2022 at 4:04 PM
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MIKE H R
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Try starting the engine and try to pinpoint the noise. They have something like a doctor stethoscope in most auto stores. I have used mine a few times, it helps with finding the correct area that is making the noise. It could be the throw out bearing but I would start by listening to the pulleys on the engine when it is running. I might be wrong, but I think {without seeing the car} it could be one of the engine pulley whine.
Sep 11, 2022 at 10:45 AM