When engine braking, I hear a loud growling/buzzing noise from the engine bay. It’s very deep and loud, not an electrical buzz. It increases in volume significantly if I’m turning as I’m engine braking. It only makes this noise in these conditions with no other symptoms than the noise. The front hubs, rotors, pads, control arms, tie rods, and shocks are all relatively new. This issue never went away as I replaced these parts. Any advice?

No codes present

 

What exactly do you mean by engine braking ?

 

Shifting into I or L on the automatic transmission down a steep grade

 

Doing that could be the the engine, like the timing chain.

 

Honestly. I don’t have a clue what it could be. Never heard a description like that before.

 

Thanks anyways. I tried to recreate the problem again to take a video but too much background noise. I think the sound might be more like transmission area. My guess is that it’s something in the transmission or torque converter when the force on it is “backwards” during engine braking. I’ll try checking all the mounts when I can get to a lift.

 

does it sound like an engine at high revs?
Engine braking on an automatic transmission is an amazing technique, usually engine braking is practiced for a manual transmission, but if you use it, then this is your choice.
To the point:
As soon as the driver stops pressing the gas pedal, no fuel is supplied to the engine. At the same time, the inertial force acts on the crankshaft, causing a decrease in revs. Thus, the opposite effect occurs when energy is transferred from the wheels through the transmission to the engine. The crankshaft does forced work, the compression in the cylinders increases and the speed of the vehicle drops. If at this time the transmission is shifted to a lower gear, the braking effect will increase, although the revs will increase slightly - the crankshaft will be forced to spin faster and do even harder work, increasing the degree of braking.
I think that this is exactly the hellish work of the engine that you hear from under the hood. The loaded engine begins to "scream" from the strain. How the automatic transmission behaves at this time, only the devil knows. But there is a feeling that such a load is not good for the unit. I sometimes use a vehicle with a manual transmission and on such trips I use both engine braking and other techniques associated with downshifting. When I bought my Chevrolet with an automatic, I tried engine braking. The effect is weak, the automatic transmission is too slow to react, it takes almost half a second before the transmission figures out what's what and starts to react. Anyway, I tried it and never did it again.

 

My bet is hubs or LCA bushings.

 

bet its a rear hub... replaced everything on my front end and still does it, I thought it was a front hub, wife says its coming from the rear on passenger side.... sounds like right front to me tho...LOL

 

Thanks all. Front hubs are new, maybe rears are due for replacement. I’ll update if that cures it.

Edit: LCA’s are both under 10k and the bushings still look new.