Hi Folks.We have a 38' diesel pusher with cummins 350 and Allison trany. Built in 2008 and has 25,000 miles.Yesterday we had a 11 mile, 3500 foot winding, descent averaging about 8%. We used the exhaust brake as usual and have made the trip many times over the years without a problem. We pull a Jeep without aux braking.When we arrived at the campground at the bottom of the mt there was a noticeable smell of smoked brakes which is the 1st time for us.I wasn't paying much attention so I guess I could have been descending faster than normal and used the regular brake more often.But if not, what do you think it could be? Air in the system was normal.Last summer in Colorado the emergency brake wouldn't release in forward gear. I put the rig in reverse, heard a loud clunk and the brake released. Could that be the problem?The exhausted brake was working but as I recall I had to brake more often to get the speed down to 20mph on some of the curves. Can the exhaust brake work but not well enough? Again, the problem may have been operator error. Just not paying enough attention. But if it is something mechanical I need to know what it can be.i have never manually dropped the transmission to a lower gear. Always relied on the auto transmission setting. On a long, curvy steep grade like this one do you manually shift to a lower gear?Thanks for your help.Dan

DanLefoot wrote:Hi Folks.We have a 38' diesel pusher with cummins 350 and Allison trany. Built in 2008 and has 25,000 miles.Yesterday we had a 11 mile, 3500 foot winding, descent averaging about 8%. We used the exhaust brake as usual and have made the trip many times over the years without a problem. We pull a Jeep without aux braking.When we arrived at the campground at the bottom of the mt there was a noticeable smell of smoked brakes which is the 1st time for us.I wasn't paying much attention so I guess I could have been descending faster than normal and used the regular brake more often.But if not, what do you think it could be? Air in the system was normal.Last summer in Colorado the emergency brake wouldn't release in forward gear. I put the rig in reverse, heard a loud clunk and the brake released. Could that be the problem?The exhausted brake was working but as I recall I had to brake more often to get the speed down to 20mph on some of the curves. Can the exhaust brake work but not well enough? Again, the problem may have been operator error. Just not paying enough attention. But if it is something mechanical I need to know what it can be.Thanks for you help.DanWhat gear were you in? Lower gear more exhaust brake. But the emergency brake sounds suspect, something hanging up.

A lot of irony here, having a brake issue with your last name being Lafoote!Mine is a gasser but guessing the same applies to a diesel. Mine is stated to use the lower gears. Mine is simple, use the tow button on the end of the shifter. And if you don't like it running real high rpms when doing it, use the brake firmly to get your speed down pretty quickly and then let the tranny do the constant braking.Another manual method is to use the same gear going down as you just used going up. Either way, I have to believe you have worn out your brakes by not using your tranny gears and it has caught up with you.Good luck

I have heard that Texas DPS truck stops use infra red cameras to id brakes that are hanging up running hot when pulling into the safety inspection stops. That could ID a bad brake' More simply next time you go down a hill using brakes crawl under an check temperatures. If one is much hotter than the others you may have a repair item.A hung up emergency brake would run hot on level ground and appropriately smell there also

IF the trany won't automatically drop to lower a lower gear. You have to do it manually. The lower the gear, the better the exhaust brake works. Not so much in higher gears

Emergency brake being stuck was likely the shoes rusted to the drum-- not involved here.Yes, the faster you go, the more braking HP is required to keep your speed in check. The correct speed of descent is one that keeps your speed in equilibrium-- you are neither speeding up nor slowing down WITHOUT USING THE SERVICE BRAKES.If a PacBrake, have you lubed it? More important if not used frequently.You need to verify that the exhaust brake is working:Get up to higher RPM in, say 3rd gear (use Allison shift pad to select 3rd). Take your foot off the throttle-- feel the braking. Toggle the exhaust brake switch ON and then OFF, back ON... You should feel a difference, particularly at higher engine RPM's.And, if they got that hot, you need to have your brakes and axle seals checked.

Smoked the brakes yesterday-update on test | Good Sam Community

ccxnola
Explorer
Feb 01, 2015
On long downhill grades, I ALWAYS use the lower gears in the Allison.
During the annual check last year, the mechanic asked if I even used the brakes - there was so little wear. Yes, I drop gears leaving the Interstate, approaching a stop light or any time I need to slow down.
Sure, the dashboard controller gets punched a lot, but it has worked for me.
wolfe10
Explorer
Feb 01, 2015
Emergency brake being stuck was likely the shoes rusted to the drum-- not involved here.

Yes, the faster you go, the more braking HP is required to keep your speed in check. The correct speed of descent is one that keeps your speed in equilibrium-- you are neither speeding up nor slowing down WITHOUT USING THE SERVICE BRAKES.

If a PacBrake, have you lubed it? More important if not used frequently.

You need to verify that the exhaust brake is working:

Get up to higher RPM in, say 3rd gear (use Allison shift pad to select 3rd). Take your foot off the throttle-- feel the braking. Toggle the exhaust brake switch ON and then OFF, back ON... You should feel a difference, particularly at higher engine RPM's.

And, if they got that hot, you need to have your brakes and axle seals checked.
Terryallan
Explorer II
Feb 01, 2015
IF the trany won't automatically drop to lower a lower gear. You have to do it manually. The lower the gear, the better the exhaust brake works. Not so much in higher gears
traveylin
Explorer
Feb 01, 2015
I have heard that Texas DPS truck stops use infra red cameras to id brakes that are hanging up running hot when pulling into the safety inspection stops. That could ID a bad brake'

More simply next time you go down a hill using brakes crawl under an check temperatures. If one is much hotter than the others you may have a repair item.

A hung up emergency brake would run hot on level ground and appropriately smell there also
L2R
Explorer
Feb 01, 2015
A lot of irony here, having a brake issue with your last name being Lafoote!

Mine is a gasser but guessing the same applies to a diesel. Mine is stated to use the lower gears. Mine is simple, use the tow button on the end of the shifter. And if you don't like it running real high rpms when doing it, use the brake firmly to get your speed down pretty quickly and then let the tranny do the constant braking.

Another manual method is to use the same gear going down as you just used going up.

Either way, I have to believe you have worn out your brakes by not using your tranny gears and it has caught up with you.

Good luck
et2
Explorer
Feb 01, 2015
DanLefoot wrote:
Hi Folks.
We have a 38' diesel pusher with cummins 350 and Allison trany. Built in 2008 and has 25,000 miles.
Yesterday we had a 11 mile, 3500 foot winding, descent averaging about 8%. We used the exhaust brake as usual and have made the trip many times over the years without a problem. We pull a Jeep without aux braking.
When we arrived at the campground at the bottom of the mt there was a noticeable smell of smoked brakes which is the 1st time for us.
I wasn't paying much attention so I guess I could have been descending faster than normal and used the regular brake more often.
But if not, what do you think it could be? Air in the system was normal.
Last summer in Colorado the emergency brake wouldn't release in forward gear. I put the rig in reverse, heard a loud clunk and the brake released. Could that be the problem?
The exhausted brake was working but as I recall I had to brake more often to get the speed down to 20mph on some of the curves. Can the exhaust brake work but not well enough?
Again, the problem may have been operator error. Just not paying enough attention.
But if it is something mechanical I need to know what it can be.
Thanks for you help.
Dan

What gear were you in? Lower gear more exhaust brake. But the emergency brake sounds suspect, something hanging up.

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Smoked the brakes yesterday-update on test

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