Differential whine/howl, case opened with FTS engineer

Noticed a whine/howl sound @50 to 55 mph for the past week coming from the rear diff. Checked the fluid level and noticed it was 1 quart low! No leaks whatsoever. Made an appointment for today and dropped it off this morning. The techs confirmed the sound is coming from the diff and contacted Toyota. Guess a FTS engineer will be flying out for further diagnosis.....

 

hmm, I have a whine/whistle at exactly 61 mph. No other speeds. Same thing?

 

IDK, maybe....mine comes on exactly @50 to 55 and lowers after 60. Dealership confirmed it is 100% from the differential. I'd check gear oil level, my shit was low from the factory.

 

Front different or rear diff?

 

How do you check the fluid level for the rear diff?

 

Rear.

 

Thanks!

 

This. I added a quart and was still barely touching oil....

 

If you do a drain and fill you should probably fill to recommended capacity. When your shit is howling and whining adding to the fill hole probably wont hurt...

 

Congratulations.

 

What kind of response is that?

 

My bad. I thought he was jabbing me for filling to the fill hole. I'm a little edgy from this situation haha

 

I get a very tiny howl at around 55-60 when under no load (accel or decel load makes it go away), typical of a little play in gear lash but not enough that I'm going to sweat it. Actually checked fill ~1 week after delivery and found it acceptable. Will probably swap gear oil for Royal Purple sometime in the spring and call it good.

That SOP as far as I'm concerned.

 

I agree. It isn't extremely loud by no means but distinct at those mph. Dealer was told to compare to other 16's on the lot and not one could duplicate....

 

I think (in my case anyway) duplicating the noise with a truck off the lot could be difficult because simply coasting at 60 is enough decel load to make the noise go away. Needs a touch of throttle to get to the sweet spot. The M/T trucks don't sit around too long so comparison with a lot truck would likely take place with a slushbox. I could see it being near impossible to hit the mark with no direct gear control, but maybe, what do I know. Never learned to drive an auto and I'm probably too old to learn now.

 

See mine howls/whines louder on decel at 50/55. It starts upon accelerating to 50/55 but is louder when decelerating....

 

Haha like you use your finger.

 

I use my dick. Yeah it fits.

 

Guys all trans diff and rear fluids should be checked warm. Just an fyi.

 

Pretty sure loud on decel loading is usually a sign of gear mesh too tight whereas I'm pretty convinced mine is a hair on the loose side. Either way, good luck. I hope Toyota gets you sorted quickly.