Loud manual transmission

Hi. I drive a 1998 honda civic 5 speed manual transmission. The transmission is loud in all gears(including reverse) nearly all the time. It is not exactly a grinding sound, but that is as close as I can describe it. When taking off from a stop, sometimes it won’t initially make the sound, but around 15-20 mph it will start to make the sound in 1st or 2nd gear. Once the sound starts, it won’t go away. I can’t link the time when it starts making the noise to any particular RPM.

I’ve hard the car for 5 years and 50,000 miles and it’s made this noise the whole time I’ve had it. It is annoying more than anything (shifts smoothly, clutch not slipping). Someone who looked at my car shrugged his shoulders and said “when the clutch goes, put in a whole new transmission, that will probably fix it”.

Curious if anyone has any idea what it might be. Not looking to put in a new transmission just to fix this noise but if there is some other simpler fix I’d be interested.

Has anyone tried changing the gear oil in the transmission?

Tester

Nope. Thought about that but didn’t think new gear oil would fix a sound like this.

What does the noise sound like,whine,high /low , rumble, any vibration?, same at all speeds? Even when turning? Jack up the car safely on stands, run engine in gear. Does the noise sound different when heard from outside of car. Locate-able from outside?. DO NOT get under car. May be bearings in half shafts. Some transmission have bearings. Does the transmission have the proper fill and grade recommended for that tranny.Get a manual on the car.

Could be a bad bearing/s in the transmission. My 2003 civic 5spd has a loud throw out bearing will get it replaced when the clutch goes.

Check to see if an exhaust system heat shield or a body part are not overly close to any exhaust system part. The vibration transferred to the car body can sound like a failing transmission gear.

Sounds like you just need a competent Honda tech to diagnose it. You are not describing anything that should be hard to figure out.

I have an '03 Honda Civic with a manual transmission and I change the oil in the transmission about every 50K miles. Also, Honda has a specific fluid for the manual transmission but says you can use 10W-30 as a “temporary” substitute. Meaning the 10W-30 should be replaced with the Honda transmission fluid as soon as you can get the Honda fluid.

I’m sure changing the transmission fluid with Honda fluid wouldn’t do any harm. It is possible the transmission has had the wrong fluid in there all this time, or perhaps it is low on fluid. There are a lot of spinning shafts and parts in a manual transmission meaning lots of bearings. A bad bearing(s) could make the noise while the transmission shifts OK. Eventually a noisy bearing will fall apart and fail completely and that can take out more parts in the transmission.

See if the fluid change helps. If not, your decision is to keep driving until the transmission falls apart then replace it with a used one, or tear this one apart and replace worn parts.

I’m going to go along with Wha Who? on this and consider the possibility of an exhaust system or heat shield problem.
That’s certainly not a rare problem and can come across as a grinding type of sound with the transmission being blamed.