WheelCollider sleeps at work

Main characters: 1 8-wheeld transport, 2 boxes, box with rotation 45,0,0.
Situation 1: transport stay on box by 4 back \ 4 front \4 left\right wheels, other part of wheels stand on same box. Second box deleted, car starts falling slowly like it's in the deep water.
Situation 2: Car on box wit x.rotation 45, box deleted, same slowly falling (turning) in same step (front\back\left\right 4 wheels hit ground and gose "sleep-falling").
What i need: normal falling- if any side of car don't get any surface under wheels - it gose falling, hard and fast as real, not like in the deep water.
Try to solve problem by: permanently - Rigidbody.WakeUp(), addforce on UNgrounded wheels, set brakeTorque to 0, set to 0.0001 wheel params, Rigidbody settings about sleep, Rigidbody mass & gravity settings, time settings. Nothing helps.
So, any helps \ ideas?

*UPD Add screens of problem, made simple and fast. (And yess, "play" turn ON).

 

1. Are your rotation values frozen in the rigidbody?
2. Try to make the collider of the vehicle the size of the vehicle?


3. If everything fails, give every wheel a rigidbody

 

You don't need to wake the rigidbody, looking at you images the issue is the wheels are floating in mid air not attached to anything, extend your cube so it properly represents the size of the connected mass, ie it should be as long as the wheels...then ensure you have the correct mass for the rigidbody.

 

1.Fresh scene, obviously - no
2. Yep & up their counts to 6 + change their positions.
3. It'll be too heavy in final result

Mass try from 12 to 1350. Same...

 

Can you either post a new screen shot showing your new setup or, post the scene, the issue your describing is easy to recreate by making the cubes collider too small, but I can't recreate it with it at the correct size.

 

2 box 25,1,25 size - ground. 1 box (default) + Rigidbody mass 12, Drag 0.2, Ang.Drag 0.3, Gravity ON. Wheels set - L/R position 1, F\B pos 1 and 2. WC set mass 1, rad 0.5, WDR 0.25, SuspDist 1, Force 0, center 0,0.25,0 , spring 35, Damper 2-12, all Friction set to 1. push "Play" wait 3-5sec when "car" gose stable, delete one box, car stand still with 0 updates. If i wakeup rigidbody, it falls, but, if we change main collision on 5-6 big collisions, after rigidbody.wakeup() it stay in mid of slipping & waking up... Main problem - without waking up RB, i'v don't get rb\wheel update for normal falling.