Manual transmission 3.5-chatter under load

Maybe some of my TW MT bro's can help because what started as an only sometimes noise is becoming more prevelant and common. Read on.
And some of you may have the same issue at some point in the near future because I have a feeling it's related to wear and tear.... at least I hope. Anyways. Figure most of you also have to be close to clutch changes soon ?
Noticed a minor chatter noise only during acceleration and only when giving anything past 2/3 gas pedal. (Under load). When accelerating in 2nd and when accelerating in 3 rd. Haven't noticed in any other gear (yet). Also MUCH more easily duplicated "chatter noise " when accelerating in same gears and when towing trailer. 3800 lbs.

It's a hard noise to explain but chatter is the only word I can think of. Almost like the sound that happens when your chugging the trans in too high of a gear. Like when you try to start in 2nd or 3rd gear for example by mistake. Been driving MT for 20+ years , so yes I know how to drive properly , but anyone who drives MT on any vehicle knows that sound I'm talking about to try and describe it.

My first thought without doing any reading was that my clutch is just starting to show wear. Started happening ~ 100 000 km and I feel a very small "disconnect" in the acceleration and momentum when the chatter happens. Very small. You'd have to be driving to feel it. Bearing?

The more I read , the more I doubted the simple fix of simple clutch wear though... lol. Also when I considered clutch pick up and shifting etc all seems good, generally speaking the clutch drives well otherwise and shows no sign of other common typical symptoms.
If I start with replacement I'm hoping to build a full OEM parts list at the very least from a discussion here so I can get this gremlin addressed sooner than later. And maybe. Just maybe one of you have had a similar issue and can shed some light. Although from my reading I didnt find anything that sounded the same with the 3.5 specifically. Although use of "chatter" is very common in transmission issue threads.

I first noticed the noise at about 100 000 km occasionally , and Im now at about 130 000 km. And now, after completing a ~ 1400 km trip through the Rockies towing our trailer ( 3800 lb) its not occasional chatter when accelerating in 2nd and 3rd. It's almost every time when under harder load. Trailer hooked up or not.

2016 sport. Usual maintenance and MT fluid changed with typical Red Line fluid at ~ 80 000 km.

 

Saved.
OEM Transmish Parts list.

 

Hmmm. No rpm changes when you hear the noise right? I would grab some of the used redline fluid and send it to black stone labs.

 

Could be the Clutch plate slipping and grabbing???
Maybe. I can't imagine it being a problem in the transmission.

 

I don’t have an answer for you but I have had something similar I think.

It usually seems to happen if I’m on a 60ish mph road with a sudden steep grade, steep enough that I have to downshift to third and with heavy throttle in 3rd at like 3500 rpm there’s this chatter. I sorta got familiar about it because I used to regularly drive a road with that scenario.

Honestly the more I felt it the more it just felt like an odd resonance making it’s way into the cab. Haven’t really been given much reason to suspect anything else.

 

My experience with clutch chatter over the years has been worn clutch plates and/or oil getting on the plates from a leaky rear engine seal.

 

Sounds like weak fingers on the clutch pressure plate. Over time due to wear and heat they weaken and in extreme cases the fingers will seperate. You will usually feel a shudder when pulling away from a stop light or under heavy loads. Perhaps hauling the trailer has accelerated the wear on the factory clutch and pressure plate?

Does it become more pronounced once you've been driving for a while. Heat will make it worse. Hauling weight up grades in 5th or 6th can cause mild slipping resulting in heat build up.

Just my 2 cents. If you are going to keep hauling that trailer consider a good quality aftermarket clutch. Ive had friends use the "puck type" clutch but apparently the engagement can be too agressive. If you change clutch do some research first on heavy duty options.

Good luck!

 

Every situation you have described are ideal conditions for pre-ignition (aka:spark knock, octane knock, ping, detonation).

Try running a tank of name brand (Mobil, Sunoco, Exon, etc) 91 octane premium grade fuel, see if the noise is reduced or eliminated.

Please report back your findings.

 

What rpm are you at when you start accelerating? Possible you might be to low.

 

if it were the clutch more than likely U would experience symptons at the point of engagement

at the rpms U mention its also likely U would experience a washboard type of feeling

yet U simply mention a noise

at Ur mileage ‘ pre-ignition ‘ is a likely culprit

next time U change plugs label keep in order

check compression values.........take

really close up photos wl likely show a cylinder or 2 very dry valves

 

Nope. Consistent RPM through acceleration. I haven't watched tach but I'm guessing it occurs somewhere around 3k.

I could gather some fluid. I'm going to get under there again and top up fluid just to be positive it's at the fill line. First couple of inspections underneath didn't see any signs of leaking or sweating.

 

This sounds like a similar scenario based on the demand anyways. Did momentum/ acceleration seem constant when the sound happened ?

 

Alot of my reading has pointed to this direction as well. Contamination or wear of the plates. So I'm leaning towards pulling it and checking it out.
The rear engine seal I have zero experience with though on this motor. Although I have printed the spec manual someone posted on an older thread. I'm guessing it's not something I do at the same time as clutch?

 

I would say trailer towing has definitely accelerated it. Although a bit more time to drive and confirm post trip will confirm.

I strained the Ole camry motor and transmission on the trip. If anyone knows the Alberta to BC highway, there are some decent extended grades during the drive. A bit of practice on the down shifts and knowing the which gears for the hills though the Taco did well I thought. Not the fastest but able to keep a safe pace anyways.
For steep grades I held 3rd gear at about 80km/h and kept the RPM and pedal to about ~3k. That seemed to be the money spot for hills and kept shifting to a minimum.
I was watching the MPG for fun also and noticed I might get worse MPG in 6th gear on flatter roads with pedal almost fully in, Versus staying in 5th and keeping in about half way to the floor. Averaged about 12 MPG on the trip. Never over 60mph /100 km for longer than a minute or two. The trailer (single axle) and Taco settle in nicely around 90-100.

Funny you mention aftermarket parts though. I was thinking the same thing but after some reading on here as usual too much TW anxiety followed lol. I'm not ruling aftermarket out but OEM is my hope at this point...just can't find enough info and support on aftermarket.

 

Excellent points. I ran a full tank of 91 from Shell (only use Shell whenever possible) before and during the entire trip in preparation because I was expecting prolonged steep grades etc and wanted the most boom boom on the hills.
I'm still on 91 and finding the sound is more consistent now. Almost every 2nd and 3rd acceleration under harder load.
No trailer attached.

 

I'll try messing with the RPMs a bit on up shifts. But I like I'm high enough. Usually 2k or more I think.

 

Wash board affect. Like a shudder ?
This is kind of what I feel also if that's what you mean, maybe didn't do a good job explaining it. But you know that feeling or shudder when you're in the wrong gear starting off ? It's quick but there.

Should have mentioned I also just did plugs about 10 000 km ago and compared pics I took to other threads on here and it seemed "average". Although I'm no pro or mechanic.

Did not check compression though.

 

OP are you on bigger than stock tires? I'm on stock size tires and shifting at 2K for me results in spark knock, that said I am at high elevation. Bigger tires would make it even worse for me.

 

My tried and true clutch test method:
Next time you're out on a stretch of highway with lots of room around you. At about 100 to 110km/h in 5th or preferably 6th. Keep steady pressure on accelerator. And start applying brake. Drive with two feet for this. If your speed and RPM don't both fall then you've got slippage. If speed falls and revs stay same you're slipping. The shudder might present itself at this point as well.

Back in the day that was my go to clutch test on a used car. If that clutch is getting weak it will show.
Just be careful around traffic. Do it on a quiet stretch of road.

Hopefully your revs drop with brake application then its likely spark knock as stated in other posts.

Good luck!

 

Another thought....I drive an 07 taco (bought new) At around 100-150000km mark I remember the cluch disc started chirping every time I left a light. Annoyed the hell outta me for a year or so then went away. I assumed I must have glazed the clutch disc by riding it at some point. Figured I'd just keep driving it till it started slipping. At 292k now and it feels better than ever. If its not slipping keep driving...its a Yota I've had dozens of them, all manuals. They heal themselves sometimes