Odd issue w/ new 2021 TRD OR 4x4. Electrical? Diff lock?

I’ve had a 17 & 19 in the same configuration (TRD OR 4x4 long bed) with none of the below issues. Only thing I can think of before I take it into the dealership for service is to disconnect the battery.

Faint “motor” sound often, almost like the truck has airbags and they are inflating or deflating (when braking, accelerating out of a stop light, etc). It’s been very loud and noticeable a few times when getting out of truck just after reversing and turning off the ignition.

Sluggish performance & odd sounds when braking after going a high rate of speed like coming off the freeway or when reversing and accelerating. Sounds as if something is lightly clanking around in the muffler (best way I can describe it)

Truck shudders some when brake applied sometimes.

Could all 3 of these have something to do with the motor that runs the rear diff lock and the locker having issues? I test drove the truck and put it in 4Hi & 4Lo and engaged the rear locker and everything worked great literally a week ago when I bought the truck.

Pulling to the left (might be a separate issue.

Thanks

 

It's the hydro boost braking system. It runs a pump regularly to recharge the accumulator. It's integral to normal braking and all the advanced functions like EBD, BA, VSC, ATRAC/MTS, TRAC, ABS, etc.

It has nothing to do with the rear diff lock. The diff lock uses no motor and is actuated by a simple integrated solenoid.

 

Thanks. Never experienced hearing the pump in my previous models.

Any idea what the other complications could be?

 

Seems to be luck of the draw. Some people hear it and feel it in the pedal and others never notice it. I never feel mine or notice it driving but if I pay attention I know it's there especially with the truck not running. I didn't buy mine new so I can't tell you if it gets better over time.

 

The “motor” noise may be AC expansion valve resonance, which is just a design quirk and nothing to worry about. Here’s a thread with a video to see if it’s the same noise you’re hearing...
https://www.tacomaworld.com/threads/whine-during-acceleration-update-finally-got-it-on-video.672022/

I can’t say I’ve had any shuddering or brake noises on mine at all.

 

FYI the 3G diff lock is not run by a motor, like the diff lock was on the 2nd gen. It’s a magnetically activated ring than sucks in a plate that locks the diff.

 

Might be something other than the electric brake booster, its completely silent and vibration free in my truck.