Smart Shift won't go into gear

[Shimmy1]

2006 Freightliner Colombia with C13. I forgot to get the VIN, but we believe it has a Eaton AutoShift with the centrifugal type clutch. It has been growling when engaging for a while, but once you're moving works fine.

Today, driver called. Said truck wouldn't go into gear. Shut truck off for a few minutes, started, went into gear, drove back to shop. Tried to drive into shop, would not go into gear even after shutting off. Pulled in, let sit for hour. No trans light, when it won't go into gear the display just blinks the down arrow and 1, like it does when it works. Also, there is a slight humming or whining noise when it won't go into gear. Apologies that I don't have much more at this time.

Transmission looks like this.

 

[Shimmy1]

.

 

[Vetech63]

This is TS material. All i see looking at that pic is AIDS.

 

[Shimmy1]

This is TS material. All i see looking at that pic is AIDS.

You're not alone. Problem is the other guys get pretty desperate for help sometimes, and they'd rather spend money on this than let them tear up the big trucks.

 

[Truck Shop]

Clutch.

 

[Shimmy1]

Did some diagnosing today. When the input shaft does stop, it goes right into gear. The humming/whining/chatter we hear is apparently hydraulic noise? You can feel the noise in the main oil line on the side, slightly in the little line that goes to the inertia brake. The centrifugal weights are moving, if you rev it up to 1400 and let off quickly, you can feel and hear them shift. Leaving your foot off the brake pedal, if you rev it up just right and let off just right, you can get the brake to stop the trans, then it shifts into gear. When this happens, that hydraulic noise goes away.

We know it probably needs a clutch at some point, but that stupid inertia brake is $2200. Do you usually replace that brake when you replace the clutch? The truck has 970k on it, we have no idea of the history. Is there any way whatsoever to determine if that brake is bad or not, or if something with the oil supply is causing this?