Engine braking now vs then.
In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the ...
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Old-Biscuit wrote:
"In 2009 I towed our 5ver over the Creston Salmo pass in BC with an 03 Duramax. I manually placed the truck in low gear and listened to the engine rev to over 5000 rpm as it struggled to hold back the gcvw of about 21000 lbs... about 35 mph."
2003 Duramax LB7-----REV Limiter set at 3250 rpm
:H
I have a US Gear 4" exhaust brake on my 5.9L Cummins
Truck/trailer combo 22k
Exhaust brake 6% grade----55 mph
Glad to see exhaust braking OEM ------ great tool for diesel trucks
nope! duramax with grade brake or exhaust brake shuts off fuel and will rev to 5000rpm. friction increase as the cube of RPM so doesn't take much increase in rpm to increase braking.
If duramax goes above 5,000 it will shift up a gear regardless of what the gear slector is in. That's why the tach goes to 5K. And why GM eliminated the redline above 3200 because people weren't reading the diesel suppliment owners manual on how the grade brake/exhaust brake works and what rpm it can go to.
To the OP's comment. I had (son now has) an 04.5 duramax with grade brake only, and now a 15.5 with exhaust brake. While the grade brake feature provides significant retardation, it is no where near as effective as the exhaust brake.
