PLEASE HELP, I am so lost!!

[2010-Runner-Trail]

Ok yall I really need some help. I have been chasing this forever now and I am SOOO sick of it I find myself not even wanting to drive my 4runner.

Here is the deal, while coasting I get a grinding noise that sounds like its coming from the Tcase. I have replaced the tcase, both driveshafts and all u-joints. It still happens. The faster I go the worse it gets. This only happens when there is no load on the drive train. If I am using the engine to break or accelerating the noise goes away. Here is a link to a video of the problem, sorry its shot at night.

https://www.youtube.com/watch?v=Euy8xB9J_3E

Please any help would be greatly appreciated!! :yo:

 

[4Reak Show]

Probably transmission bearing my friend. When accelerating (and I also believe engine breaking) you're putting load on one side of the gear teeth (called the drive side for obvious reasons)

And when coasting, the driveshaft is pushing the guts of the transmission from the other side of the gears (called the coast side as you can imagine why). Likely a bearing in the mainshaft or countershaft gets cocked just right and makes the noise.

That's my guess anyhow.

Good luck.

 

[2010-Runner-Trail]

Thanks for the input. May be pulling the tranny.

 

[gm350reratliff]

Hard to tell online here at work since the PC speakers suck but it sounds more like a vibration possibly from a transmission mount or exhaust pipe rattling against something. I would find someone with a 4-post lift and see if you can replicate it while you can look underneath.

 

[4Reak Show]

Duh haha. ^^^ totally forgot about replicating with rear wheels off the ground and a stethoscope. I'd do that before yankin trans.

 

[nglayton]

Throw out bearing? Clutch disk failing? But I assume since you swapped the xfer case you checked those. Main bearing? or the Transmission are about all that's left.

 

[dms1]

Sounds like the throw out bearing on the Clutch

 

[RBE17]

That sounds rough. I'd try and replicate it w/ all four tires off the ground and check for rubbing. It might be something very simple, but if you pull the trans, check everything. No need pulling it more than once.

FWIW, I chased a whirling in a 95 Trans Am that only happened if the car was in neutral. If I pushed in the clutch, all was fine. Under load, all was fine. I pulled the trans three times in a week. Each time I replaced the pilot bushing in the crank shaft. On the last time I used a brass bushing instead of a bearing. All whirling went away after that. I couldn't believe it.

Good luck.

 

[BlackWorksInc]

Throwout bearing? Did the OP swap in a manual from a Tacoma or FJ?

 

[4Reak Show]

Noise coasting in gear = throw out and pilot bearings aren't in use (flywheel and trans input spinning together, so pilot bearing isn't spinning. foot off clutch pedal means throw out bearing is retracted and not spinning)

My money is still on internal. Running in the air with stethoscope is the next best option in my humble opinion