Odd noise when car is decelerating (1 Viewer)

[dsagona]

Hi,

I have an odd noise from my vehicle that I’m hoping you can help me diagnose. I notice it when I’m going around 30-50 mph (it could be there when I go faster, I haven’t tried yet though) and remove my foot from the accelerator. As the car starts to slow down on its own, I’m getting this odd rattling or screeching sound. It doesn’t really happen when I apply the brakes, and goes away when i press the accelerator again. I uploaded two videos to YouTube for your listening pleasure. Thank you!

 

[tacocat]

Lifted?

 

[dsagona]

Nope, all stock as far as I know (I just recently bought the LC) but definitely not lifted.

 

[categorytheory]

Transmission maybe....? Gear box? Does it only do it while moving? Can you recreate the noise while parked and revving the engine?

 

[ajax1]

Ujoints in drive shaft

 

[1911garand]

I'd start with inspecting and lubing driveshafts, slip yolk splines, and joints.

 

[dsagona]

I just went out and tried to recreate it when parked and revving engine. No noise. What’s throwing me off is that it goes away at the slightest increase in speed after I’ve removed my foot from the pedal. I’ll keep exploring. I was told I need a new king pin, could that be the culprit?

 

[deltapine1]

I am not sure what year you have but I had a similar noise and it was an emergency brake shoe lining that had come loose from the shoe and was dragging inside the rotor.

My noise was a faint oscillating squall similar to loud crickets on a June night. It only made the loud cricket noise when coasting.

I never tried it but in theory if I had pulled the E Brake up slightly while coasting the noise should have stopped or changed tone.

 

[BILT4ME]

Check your fluid levels and quality in front and rear differential as well as transfer case. Could be loose pinion bearings, loose parking brake parts, wheel bearings, u-joints, and many more things.

 

[jonheld]

If the noise occurs at the sweet spot when you're coasting, neither accelerating or decelerating, then it is likely drive line related.
This is typical of warn slip yolks in driveshafts as the 2 halves will "flop around" with no load at speed. Slip yolks should have zero torsional play.

 

[mudgudgeon]

I just went out and tried to recreate it when parked and revving engine. No noise. What’s throwing me off is that it goes away at the slightest increase in speed after I’ve removed my foot from the pedal. I’ll keep exploring. I was told I need a new king pin, could that be the culprit?

Classic symptom of toasted uni joints

 

[uzj100]

Got in some deep water wheeling and now have the whirring when i lift off the gas. I am going to grease all u joints and start there.

 

[BigredTEX]

I know the transfer cases are relatively bullet proof, but this sounds like an issue I'm fixing right now. A bad rear output bearing in the transfer case. Exact same symptoms and similar noise.

 

[uzj100]

Thank u. Starting with u joints and will go there next. Thank u.

 

[jsreese76]

I’m having this exact issue and have for months. Did you find a resolution to the noise. I’ve had 3 factory techs and off-road shop and a Toyota master tech look at all these. Dropped the diff fluid and sent to a lab.

Any help is appreciated. It’s my daily driver so I’m about to trade the car I loved. The noise is driving me crazy.

 

[dsagona]

I’m pretty sure it was my driveshaft (propeller shaft?) to the front axle. I rebuilt the axles and braking systems on all four corners of the LC. I also changed all of the fluids on the car during this rebuild, and removed the fuel injectors and had them cleaned. The noise was still there after all this work. I planned on doing these projects regardless of the noise, so I wasn’t too upset when the noise was still there after I was done. I took the car to my mechanic to tidy a few things up and to get an alignment done. He ended up replacing the driveshaft and the noise was gone. I hope this helps.

 

[jsreese76]

I’m pretty sure it was my driveshaft (propeller shaft?) to the front axle. I rebuilt the axles and braking systems on all four corners of the LC. I also changed all of the fluids on the car during this rebuild, and removed the fuel injectors and had them cleaned. The noise was still there after all this work. I planned on doing these projects regardless of the noise, so I wasn’t too upset when the noise was still there after I was done. I took the car to my mechanic to tidy a few things up and to get an alignment done. He ended up replacing the driveshaft and the noise was gone. I hope this helps.

Thank you for taking time to reply, and I have done everything else you mentioned except for the drive shaft and I am betting this is gonna be an extremely helpful reply. I appreciate it and I appreciate the feedback from the community. Happy mudding.

 

[Broski]

Pull the drive shaft and lock the center diff and go for a spin.
If the noise is gone you know it’s the DS

 

[jsreese76]

Pull the drive shaft and lock the center diff and go for a spin.
If the noise is gone you know it’s the DS

Great advice. With a scope and the car on the rack running freewheel you and hear what might’ve a roar in the diff. That’s why I asked for a sample set it off the lab however the flu it was almost brand new so you have a great analysis point. Thanks for your input.

 

[BigredTEX]

I have had this noise since I built my rig. It had sat in a field for 10 years prior to my acquisition. This noise was there at the first test drive after rebuilding both axles and disassembled and inspected the xfer case. Since then I have rebuilt/re-geared the xfer case and replaced both drive shafts with custom built units. Th noise is better but still there. I'm convinced it is in the transfer case. When it's making the noise it can be felt in the transfer case shifter. In addition, I have done the remove the front drive shaft and lock the xfer case experiment and the noise is still there.