[Shop-talk] An off shoot of the Toyota debacle.....

[Nolan]

You're right, it's not 100% and 0%.  There is some force that can go the 
other way.  I don't know the effectiveness ratio.  I do know it's not 
much.  I've never driven a gasoline engined vehicle that had much engine 
braking, even with a manual transmission.  The engine is way too low in 
compression to give much.  A diesel, yes.  That's a different critter.


>
> OK, I've been trying to stay out of this thread, but if this is true, 
> how is it the engine can slow the car down when the driver lets off 
> the throttle?  To get engine braking the transmission must be pushing 
> against the engine and the engine must be resisting the force through 
> the torque converter.  This is true without regard to whether a 
> modern, lock-up converters is being used or not.  Torque converters 
> must be capable of transmitting torque in both directions or there 
> would be no engine braking effect.  There may a difference in 
> efficiency between the two directions, but its clearly not 100% one 
> way and 0% the other.