what is a clutch brake?

The first few inches of clutch pedal travel will release the clutch pressure plate, disconnecting the engine from the transmission.


If you keep pressing the clutch pedal down you will engage the clutch brake .... which will stop the transmission input shaft from spinning and allows you to shift gears when your truck is stopped and the output side of the tranny isnt moving.

You cant shift gears in a heavy truck transmission without getting everything spinning at the proper speeds .... when your truck isnt moving the output side of your tranny isnt spinning so you need to stop the input shaft from spinning .... this is what the clutch brake does.

You ONLY want to engage the clutch brake when you are stopped.


A better name for it would be the "Transmission Input Shaft Brake"

 

Great way to explain it...just wish you'd have been around 13 years ago when I was tryin to figure that out!..lol

 

I know this is late but before attending trucking school I’m reading and educating myself on these things and man you explained it well! I was confused at first lmao salutteee to you

 

Great reply (and I know this is an old thread but has valuable information for new drivers). Once a clutch brake is gone you can't get it in gear from a standing start AND double clutching can be an issue.

I've driven hundreds of trucks for customers, many have clutch issues. Recent I drove an overweight load from PA to ND with a clutch brake that was gone. It was impossible to engage any gear from a standing start. So how did I drive that truck all that way safely?

If I was at a standing start I GENTLY would nudge the shifter towards the gear I wanted, feeling the constant turning off the gears at idle, with the clutch depressed to the floor board. Then WHILE still gently nudging the shifter I turned off the engine. Sometimes the shifter would drop right into gear as the engine came to a stop, if not I turned on the engine and it would drop right in as the gears started to move again. All this was done with the clutch depressed to the floor.

Once I was in gear and wanted to proceed I drove it as I normally would, floating gears. Double clutching was out of the question.

One other thing about that truck was it had a thirteen speed. The only good way to split high range was to take the shifter back out to neutral and float it back in. Otherwise there was a hard "clunk" on the split.

That truck had 180,000 miles on it. Do you think it might have had a few rookies abusing that drive line?