Knocking noise. Starting to scare me

So I have an occasional knocking noise coming from the truck, and I believe it's the engine. I say occasional b/c it's not constant, but it's very frequent.

Most of the time it happens when I'm in too high of a gear for the speed or situation. So for example, cruising at 35 and going up a hill. Instead of mashing the gas to prevent speed lose, I'll just keep the same throttle. Nearing the top of the hill there is a very noticeable knocking noise. Not a high pitch, but a deeper noise. Once I let off the gas it stops.

Also, can make it happen if I'm cruising in traffic slowly when the RPMs are low(around 35-40), and then give it a good bit of gas (but not floor it to cause an instant gear change.). Before the truck down shifts, there is a noticeable knock.

Truck is a 2010, 130k miles. Dealer maintained it's entire life. With the stereo on, I can't hear it. I would almost swear this never happened before I had the transmission serviced at the dealer 10k miles ago, but could be a coincidence.


Any thoughts? I've heard that these engines are noisy buggers, and of spark knock. I'm not exactly sure what spark knock sounds like, so hard for me to write it off as such.

 

I'm gonna go with a wild shot here and say it could be an engine mount is loose. Granted noises can be one half a million or another until someone can eyeball it. I say an engine mount because stop and go traffic and normal wear and tear could lead to the mount failing. And in most engines they are mounted resting on a rubber bumper. Naturally this rubber bumper doesn't last forever and its purpose is to allow a slight give when the engine is under torque. Similar torque to what you have described. Good luck! Its a start at least!

 

Have you greased the driveshaft u-joints and checked the center bearing for excessive play, lately or ever?

 

It's from lugging the engine, it's rod knock.

You gave a perfect description of both the technique that causes it and the sound.

If it were manual, you'd be driving it incorrectly, needing to downshift, because just as you say 'it happens when I'm in too high of a gear for the speed or situation'.

In the short term, either manually downshift or give enough gas to make it downshift. Manual downshift would be what I'd do.

In the longer term, I'd see if the trans needs adjustment. Sounds like it's out of sync with when it should downshift. Forum member gearcruncher may have some input on this topic for us.............

Does it ever seem to hang on the upshifts? Like take too long? Over rev during the shift?

 

Clearwater Bill has it right.

 

The only time I really notice a high rev issue is when I roll out of parking lot that is on a hill and I'm heading down the hill. When I give it gas it will high rev, like the truck is in neutral. To avoid this, I can give it more pedal before I roll out and it will shift to second before momentum is carrying the truck down the hill.

Think they messed up the trans service at the dealer, and that's causing the issue? Maybe too low of fluid?

Rod knock sounds like a bad thing. Is my engine doomed in the next 10k miles or am I ok?


As far as maintenance, this thing has been taken to the dealer every 4-5k miles since new. All required maintenance was done by them, so it should be up to date on everything. But, to answer your question, No, I have not personally checked for play or greased anything.

 

One more thing. Sometimes the noise sounds a little different. Knocking to an extent, but almost with a gurgle/rattle noise to it, if that makes any sense.

 

Could be spark knock try a tank of premium fuel see if it goes away. If it does it's probably caused by carbon build up. give it a shot of "sea foam" or equivalent then run the s%$t out of it for a few miles to clean it out

 

My first thought cause it only happens at low rpm's,
just for shits & giggles unbolt the air box on the pass. fender,, you'll see the air horn that goes thru the fender with foam tape on it that's probally compressed allowing the plastic to hit the fender which will cause a vibration.
Can't hurt and it only takes about 10min to take off and go for a ride.

 

I can tell you my experience.. I had the exact same noise a few weeks ago after a trip. Scared to death my trans or engine was gone. Turned out to be the stock air box popping around took 10 minutes to fix check make sure everything is tightened down and check where it goes into the fender.

 

I have exactly the same issue with my 2012 Tacoma with only 42k miles. It has been going on for about a year. At first I thought it was just a bad batch of gas. After it continued I started using mid grade fuel and then premium. Running premium gas seems to pretty much eliminate the knock, but I shouldn't have to spend the $$ for premium gas when the engine is made to run on regular. At my last service I mentioned it to the Toyota Service writer and he said to try injector cleaner. So far injector cleaner has done nothing. I am still looking for a solution.

 

Ranger71, Read this thread http://www.tacomaworld.com/forum/2n...14-feedback-engine-ecm-reprogram-pinging.html

On page five I posted a video of the sound people are hearing. The TSB has fixed this in my truck. It took less then 30 min to flash the firmware and completely stop this noise. plus it made my truck and many others run smoother.

 

I think I may have the same noise in my. Truck.. Almost sounds like a crackling noise while accelerating

 

^^^^This! I had the same issue. Dealer flashed with the TSB fix and I was all fixed.

 

What the heck does tsb stand for. I see thiseverywhere

 

Means technical service bulletin. They aren't recalls, but Toyota is acknowledging that it is a known problem.

 

Thanks!

 

I have been experiencing the similar knocking sound, though I cant pin point if it's from the engine or the driveline below. It comes and goes quickly and not easily duplicated. I'll strap a GoPro in the engine bay and under the truck to try to record this. My guess is the slip yoke needing a regrease.

 

I had the same thing happen with my Ford Sport Trac..about 20K later the engine ate a rod and engine seized. It started with MAF sensor out of whack. I later found out it was a design flaw in the engine and Ford decided to go engine experimenting. Hence, now a proud TACO owner =) YEAH!!

 

Just had my '14 reprogrammed and noise is gone. I lived with it for 35k miles. Averaging 22 mpg too, far better than my 07 4Runner.