"Normal" 3rd gen manual trans noise fix

Not in the least. In neutral, there is zero torque going through the transmission.

I put noise insulation on the inside face of the heat shield. It does a surprisingly great job of killing that noise. Garden hose washers are pretty large. You'd need an o-ring or something smaller like that. But if you are in there, slap some sound insulation on there.

 

I thought it was something to do with lubrication...

 

Good point. I believe that @Jowett mentioned that there is a pump in there. My best guess is that it would be driven off the output shaft. I could be wrong, but pumping from the input shaft while idling doesn't seem necessary?

 

I'm looking to add a pump for cooling and to increase durability under the higher power circumstances in which my truck will be operating. The design of the transmission, in very very neat way, already pushes lube to all the required places via channels, holes, etc.

Coasting in neutral should be fine, but I would not flat tow for any great distance w/o the engine running.... even then.

Having a transmission opened up, my best guess while looking and wiggling gears and shafts, is that the source of the noise is some lash between gears, shift sleeves, hubs, and sychronizers. The noise rings out through the cases, heat shields, etc.

 

If this actually fixes that absurd noise, I'll love you forever. I assumed it was normal, even though I bought the truck used, it only has 30k miles.

Might throw this on it too to double tap the situation haha.

Do you have any further info on this, or a link to the TSB?

 

I missed this thread. Although I hardly ever hear the noise and don’t find it annoying, I appreciate the troubleshooting.

I was talking about this noise in a thread just the day. I got curious again and listened for it carefully while driving slowly with my windows open and radio off. I didn’t hear a thing. I have heard it many times in the past. There may have been too much background noise.

 

The noise/condition is normal, it is because the reduction gears are between the counter shaft and output shaft instead of the conventional transmission build where the input is geared direct to the countershaft instead. The reason for the noise is because the transmission internals are always spinning when the truck is rolling due to that reduction gear setup. With bumps and whatever else you can get slightly changes in speed in the wheels which can cause the transmission to switch between coast and drive just slightly enough to make clanking. Hard to explain it in a way that makes sense, but every counter-to-output geared transmission I’ve driven has been the same.

What the OP did was muffle the noise some. You’ll still feel it in the shifter if you grab it while going over the bumps in neutral.

The good news is, it won’t hurt anything but your feelings. It is annoying, but just a side effect of this design. The design is pretty good otherwise though, it results in less torque running through the drive gears, allowing for gears and shafts to be smaller and make for a more compact design while allowing the transmission to still handle enough torque for
the application.

All the TSB did was provide a heat shield coated in sound deadening that helps to cover the noise. It was not for the neutral clank, it was for a whistling noise that happens in the overdrive gears. T-SB-0186-17

 

Sorry. I don't have it handy, but slapping on some sound insulation works like a champ.

 

did you just end up using:

$30 Design Engineering 010394 Reflect-A-Gold High-Temperature Heat Reflective Adhesive Backed Roll, 1.5" x 15' Roll

$30 Design Engineering 010394 Reflect-A-GOLD High-Temperature Heat Reflective Adhesive Backed Roll, 1.5" x 15' Roll
https://www.amazon.com/Design-Engineering-010394-High-Temperature-Reflective/dp/B0039Z5TUY

 

Do you know if they honor that TSB on the latest 3rd gen years or did it stop after 17? Mines pretty loud so I can imagine it has the updated shield.

 

I have a 2021 that did not have any updated shield. I think the TSB was only performed if a within warranty complaint was made. And I don’t know if they ever stretched it into 2018+.

 

No. Just the same Noico stuff that I used on the interior. It has held up very well. I've slapped it on a couple other Tacos that I helped do the ADM on.

 

Are you all talking about the same thing? This is what most people are referring to:

https://www.youtube.com/watch?v=2aCPBaUo5rQ

 

This thread was created because of that noise in the video. OPs fix was to muffle it slightly by adding noise dampening material to the accumulator/slave heat shield. Similarly, Toyota issued a TSB to install a factory dampened heat shield on 2016-2017 trucks that had an audible high pitch whine noise in 5th and 6th gear. Two separate noises, but can similarly be muffled in the same manner. The clank will never truly go away, it is simply due to the design of the transmission. The post is just about trying to muffle it slightly.

 

Do any of you find that the noises are loudest when going over bumps at low speeds? Trying to track down a noise in my truck. Thought it was the steering rack but that video sounds pretty similar to what I'm hearing.

 

Loudest at low speeds due to no road noise to drown it out. Quietest but felt much more in the shifter at road speed due to the severity of the road speed, but don’t hear it as much because it’s under the truck and gets drowned out by the road.

 

Sweet, gonna try the gasket material then hoping for the best.

 

Mine never did that and certainly doesn't do it after the clutch line mod 5 years ago

 

Yours probably does and it just hasn't been noticed. You have to be coasting in neutral. Every manual Tacoma I've been in does it.

 

I've been wondering what this noise was! I had though perhaps my exhaust was loose and clanging when I went over low speed bumps....gonna try this mod!