Pop when downshifting

I'm posting this to see if others have observed this symptom (if it is even a problem).

I have a 2017 crewmax with about 85k miles on the clock. I noticed a hollow pop sound in the last 6 months during certain downshifts and believe i now understand the circumstances. I've had the transmission fluid changed recently at the dealership as well with no change.

The issue appears when i'm going down a long steep hill where i've left off the gas and i'm rolling until i tap the brake. When I tap the brake just once the truck attempts to downshift and begin holding back. I know that's likely a stability control feature. It's during THAT downshift that the pop sound is heard. No other shifting is it present. In fact, during all other phases of travel the transmission is smooth and happy.

I'm wondering if this is a weird drive pattern related issue i'm just now hitting or something weirder with torque converter locking/unlocking.

I searched through here and other places to see if anyone else has reported anything similar and found nothing although if you didn't realize how to recreate it that problem might appear to be somewhat transient.

All lube points have been hit regularly by myself. I've checked the drive train bolts and all are fine and been that way from day one. The u joints are fine as well as the carrier bearing.

Anything thoughts/experiences appreciated!

 

We’re you towing anything when this happened? Seems like the tranny is under decent amount of load when this is happening?

 

No.. rarely tow. I can re-create this same thing each time too. Almost like torque converter is unlocked until I tap the brake causing it to downshift and lock.

 

It’s likely your driveshafts slip joint slightly binding caused by slight axle movements when braking/decelerating combined with downshifting. It’s a common issue that Toyota deemed normal for these trucks. It is not causing any damage but can be annoying.