Weird new symptom: gear quietly grinding

MANUAL transmission.

I replaced almost my whole front end suspension. I replaced the shocks, tie rods, power steering rack, power steering hoses, steering pump, ball joints, bushings, camber/caster bolts, and steering knuckles, and the front differential. I had to touch the driveshaft universal joint. I had it professionally aligned. They didn't see anything out of place. it drives great.

Now, when I get into the car and drive it, and come to a stop at a stoplight, and put the clutch in at the light... I still feel a "tugging" on the driveline, like the transmission is still in gear, then I hear a light gear grinding "whirring" noise, and then finally, it gives up and the tugging sensation goes away and the car is fully stopped at the light with the clutch pressed in. This whirring, grinding noise only lasts a couple seconds.

It happens whether I leave it in first and keep the clutch depressed, or if I am in second, and leave the clutch depressed, or if I move the gearshift to neutral and let the clutch out.

Weird, huh?!

 

Is the clutch fork broken or bent ?

 

Not before I did this. The symptom is relatively new. And - how in god’s name do you bend a clutch fork? And why would that cause these symptoms? I cant understand what’s going on here. I can see if the clutch is depressed, the engine might still be lightly connected to the transmission, but if it’s in neutral, properly, what does that matter? I can see if it was still in a gear with the clutch depressed, then I might have a weak clutch spring or air in the clutch line…

hm.

 

It otherwise shifts GREAT. No problems between gears. I was wondering if a synchromesh could be screwed up?

 

Sounds like your clutch isn’t fully disengaging, if it does it in gear, but not neutral. You said it does it in neutral as well. I’m not sure. Could be the clutch master/slave cylinder, or needing to be bled, or the pilot bearing trying to lock up. That’s if it doesn’t happen in neutral though

 

Clutch forks bending or breaking is actually not uncommon on the early 1st gens. If I recall correctly, Toyota put a stronger one in the 01 - 04 years.

 

Have you tried adjusting the clutch pedal? The new suspension isn't going to affect your clutch, I'm sure it's just a coincidence. It does sound like maybe that bearing is going out. If that's it, the sound will be getting louder over time.

 

I am going with hydraulic clutch controls to begin but a faulty or overheated pilot bearing will also drag the input shaft . Also wondering if your input shaft inside the clutch housing is all rusty . Its not uncommon for a clutch disc to drag if the splines on the input shaft are all rusted up .
When the splines on the input shaft rust , the clutch disc has a hard time pulling away from the engine flywheel .
A cracked pivot fork is also an excellent diagnosis for his symptom . The hydraulics are strong enough to stroke the clutch release bearing ,but if the release bearing is crooked due to a busted fork , he will also suffer from a dragging clutch
Best practice would be to throw the transmission into neutral before coming to a stop rather than using the transmission to downshift to a complete stop . A little harder on your brakes but less wear to the clutch and its hydraulic components

 

Let’s analyze what could be causing weird gear noise if I do put it into neutral first and release the clutch.. then, engine is driving clutch, which is driving input shaft… which is not supposed to be connected to output shaft…
What would make grind noise for 1 second then die off?

 

total miles on vehicle ..........

miles since last clutch intervention

 

Bought it with 240k on it. Dunno when clutch was last touched. Ha.

 

Even though you have your clutch mashed to the floor as you slow down in neutral , this separates the engine from the input shaft however , your output shaft is still being driven by the rear tires .
As you coast ,The rear tires drive the rear differential , the rear differential drives the driveshaft . The rear driveshaft drives the transmission output shaft until you come to a full stop . This is called reverse powerflow .
Reverse powerflow occurs when you decelerate . There may be an issue with the different speeds of the input shaft compared to the output shaft . The input shaft to mainshaft bearing inside the input shaft where the input shaft mates with the mainshaft may be the problem . Seldom will it grind but I have seen the bearings blown to bits on high mileage transmissions .
As you coast in neutral , the weight of the truck provides a thrust load on the helical gearing inside the transmission using reverse powerflow .Its not uncommon for high mileage transmission shafts to have all kinds movement due to thrust loads . If you have ever seen inside a manual transmission , helical gears on the mainshaft oppose the helical gears on the countershaft . We are talking tremendous loads
At the bottom of this LINK , you can find a W59 transmission overhaul manual . Look at the bearing on the inside of the input shaft where the bearing mates to the mainshaft . This is called the input to output bearing . That bearing takes the load when you are in neutral and coasting to a stop . If you still hear noise at a complete stop , we gotta look at other things like clutch hydraulic controls , a cracked clutch fork , a bad diaphram or pilot bearing

https://www.tacomaworld.com/threads...on-your-5-speed-transmission-write-up.338836/

 

Good info. This is definitely gear noise. Not bearing noise. I can literally hear the gear whine. And when it comes to a full stop, when it gets slow enough, all the gear whir goes away. And you can feel ‘something’ disengage and you can ‘feel’ that you are actually in neutral now. It’s as if something was caught right on the edge of a gear to gear engagement then slipped off the end of it and is finally in neutral.

 

here's a video where you can pretty clearly hear the sound... I confirmed it grinds whether you come to a stop:
1. after having switched to neutral from gear 1
2. after having switched to neutral from gear 2
3. holding in the clutch in gear 1
4. holding in the clutch in gear 2
Also figured out that if I drive the car just a short distance forward and backward, 20 feet or so, this does not happen. Weird.

https://youtu.be/EoQJhUB8iDE

 

I’m not seeing any video.
Just for shits and giggles, what does the truck do if you were to shift to neutral at maybe 25mph, leave the clutch pedal up, then come to the stop, using only the brakes? I’m curious to hear the noise as well, but don’t forget to check all of the basics first, transmission oil level and everything. You replaced the front differential, complete housing and everything? Is it an ADD? There could be a clearance problem with the axle lock shift collar, your transfer case to front differential drive shaft should not turn, when 4x4 is not engaged.
Another thing to consider is the fact that when the 4x4 is disengaged, with an ADD axle, both cv axles turn all the time, they are not connected to each other so that means that your front ring and pinion is stationary, but your drivers side axle is spinning the spider gears in the front differential at high speeds…all the time. There is also a needle bearing that the driver’s side axle rides on inside the differential housing.
I’m just trying to help figure out if your problem is just a coincidence or not.

 

Would you describe that sound as more of a "fart"? I know someone with a car that makes that noise whenever they hit the brakes, and their problem is air in the brake lines. If you feel up to it, try bleeding the brakes and see if that fixes anything.

 

Not a fart. Very clearly gear mesh noise. Can anybody see that video?

 

yes sir
watched the video ................inconclusive to me .
Noises are very difficult to diagnose over a keyboard and as much as a video with sound helps , I am not guessing at this one .
I would suggest taking the truck to a local reputable transmission shop for a free road test .
Road tests are free .
Those guys test drive trucks with issues like this every day .
get their opinion . Did I mention road tests are free ?

 

Yes, we can see the video now. I have no idea what to tell you. Sounds like something is definitely wrong somewhere. I’m with @gearcruncher on this one, I’d hate to try and guess. Sitting behind the wheel makes a big difference. I’m actually surprised, in the video the noise seems way louder than you described it in your post. A noise that loud shouldn’t be too hard to track down. Just carry it to a reputable shop.

 

Is your 4wd working correctly? If so, does it make this noise with the truck in 4wd?