No Engine Compression Hold Back

[Jerky]

Anybody know why my 5 speed dos not hold the truck back going down long hills etc? Shifting down is not the total answer. Is this a diesel characteristic or what? My old ford, 400 ci gas engine held back real good with engine compression.



Thanks-Dean

 

[Diesel Freak]

it is not compression

A gas engine has a throttle plate to restrict air flow through the engine. The holdback from a gas engine comes from the vacuum created in the intake manifold and cylinders during the intake stroke with the throttle shut.



A diesel does not have a throttle to restrict air flow... . this is why exhaust brakes are used... . they back up the exhaust and turn the engine into a four cycle compressor.