yeoldeyoter

About 2 weeks ago i began to notice a whistling noise that increases in pitch and intensity with rpms. I attempted some troubleshooting of my own and have come to the conclusion it has something to do with my transmission. While in park or neutral, i can occationally get the whistle to occur but only at high rps 4000+ rpms with sudden acceleration. While in drive the noise will steadily increase with throttle increase starting at around 2700 rpms. I took it to a mechanic and he reckoned it may be in the transmission but wasnt sure... needless to say he didnt charge me.
I love my yota and its really dragging me down. Im open to all suggestions and information


91 4runner 3vze a340h 52000 miles 2 dents and no rust

DeathCougar

iTrader: (23)

I doubt its in the trans. I would start with the accessories in the front of the engine. Take all the belts off, and drive the truck around the block. Try to get it to replicate the problem.

yes, it will be tough without PS but at least you can start eliminating things.

The other thing you can do, is check your exhaust. Make sure there are NO leaks or open spaces where air can cause the whistle.

Matt16

Maybe someone maliciously installed a turbo when you weren't looking.

GorgeRunner

My 95 does the same thing. I also thought it was the auto transmission, but I can run through the gears by moving the shift lever, the transmission is fine, at least the guts are. The trans makes some funky clanking noises when it kicks down into the passing gear sometimes, maybe that's caused by a vacuum leak or something, that may make some noise, but I've coasted downhill in neutral with the engine on and the engine off, the noise is still there.
I've kind of narrowed down to two things; something in the rear differential, like gears "whining" (fluid is OK, just changed it) or wind noise. You may laugh at the wind noise deal, but once I had a whistling noise on my pickup that was driving me crazy, I could not pin it down. Finally, I realized the whistling was coming from a screw hole in a side view mirror I had recently installed. Filled the hole with silicone seal, no more whistling. Maybe something around the rear spoiler, or underneath the truck is doing something similar.
Since I can't pin this noise down, I figure I'll struggle with it until either something gets worse or blows up, or I accidentally fix the noise when I fix something else.
The best way to keep the noise from bothering you is to turn up the volume on the CD player or radio.

omegacore

Any more advice here? I have the exact same issue as OP

Corey

iTrader: (1)

I hope someone did not slip in one of these on your rig

http://www.youtube.com/watch?v=n79jSzKA0L8

1978elf

any solutions found for the odd whistling noise? I have the same type of issue

thnks

gjd92pickup

Is anyone's elses seem like it feels like your pulling a trailer? It only does the whistle once its warmed up and pulling out of 1st gear, I have accelerate kinda hard to pull out of stop lights because of the heavy restricted feeling when accelerating. Good news is it still does great off road and in snow!

bswarm

Restricted exhaust sometimes sounds like a hoover vacuum cleaner. Check the catalytic converter.

gjd92pickup

If I just cut the cat off and straight pipe it with the muffler will I still have the nessessary back pressure or will it be more involved with sensors and stuff?

Odin

How do you actually check the cat? I just hooked a vacuum gauge to my engine and snapped the throttle a couple of times watching for the large hg drop, which it did.

bswarm

For the vacuum test, you raise the throttle slowly. If the exhaust is restricted the vacuum will get lower as the throttle is slowly opened. Snapping it open quickly won't work for this test. Don't go too far with the RPMs, you don't want to spin a bearing or worse.

bswarm

On replacing the cat with a straight pipe, it might throw an O2 code if you have an O2 sensor after the cat. Some people get away with putting a spacer between the 2nd O2 and the O2 mounting flange. It tricks the ECM that the cat is still there.

Odin

Gotcha, I'll have to give that a try tomorrow. I don't think I have any blockage but I might as well check it out.

bswarm

If you don't have any symptoms of restricted exhaust you don't need to do this test. It'll only show low vacuum if the exhaust is restricted enough to cause driveability problems, IE less power the more you press the gas pedal. If vacuum doesn't approach about 5-10 by 3000 RPMs then stop, the problem is elsewhere. I've had vacuum readings almost 0" at around 4000 RPMs on really clogged cats. Another way is to remove the O2 sensor, or just drop the cat and take it for a quick (loud) road test. I had one car come in where the exhaust was restricted at the front y-pipe, a layer of steel separated inside and folded back, restricting the exhaust.

Odin

Not under normal circumstances.
There were a couple of times when I had the gas floored in 5th though... As I lifted off the gas I swear I could feel it slightly speed up before acting normal.

Now that I know I have a vacuum leak I'm not driving it till I can take care of that. I also installed new Denso air and fuel filters so I know they're good.... Yes fuel is flowing through the filter in the correct direction.