cummins isx 450 grinding noise

How many miles? What does it sound like exactly? Be more specific. Most ISX I see don't live past 600-800k.

 

my isx 450 has 1.3 million. oil pressure is a little weak. has front and rear oil leaks. but no blowby and still kicks butt up the hills. specially after the overhead it just got.

the problem your experiencing is the input shaft bearing in the transmission. caused from lugging the engine at 1000 rpms. your putting pressure on the shaft trying to make the truck move in a gear that's too high for the speed.

i have an 05 w900 with the exact same grinding noise at 1000 rpms. with a 13 speed.

 

Quit lugging, it sounds like the harmonic vibration at 1000 RPM is hammering the pilot bearing and input shaft.I have been told by more than 1 Cummins tech that Pre-'08 engines will self destruct if you pull on them below 1200 RPM.

 

yeah, so quit being lazy and downshift on them hills.

mine started when i dropped the idle from 8 to 6. guess not enough lubrication at the lower idle.

there's been a time or two also where i just let her drift to the top without upshifting. she'll hit about 1100.

 

I think I know what noise you're hearing, and I too think it is just the engine lugging down. Too low of RPM and too much throttle.