2000 Freightliner with 18 speed fuller transmission making grinding noise when using transmission to slow down.

[Skip02]

Truck runs and shifts perfect. I can go through all the gears with no problems but when I use the transmission and engine brake to slow down there is a loud grinding noise coming from the tranny or the drivetrain somewhere. It does it through all the gears and goes away as soon as I take the negative pressure off the tranny. Any ideas? I’m thinking it might be in the rear end but don’t really know where to start.

 

[GAnthony]

this man, @mndriver may be of some help, he too has a freightliner.

give him time to get here.

 

[mndriver]

@r3gulator3 is another resource.

If it only does it only one direction, I'd start with changing all the gear box fluids. Starting with the power divider and then the transmission.

Inspect the carrier bearing too.

I suspect it's the power divider based on your description.

 

[mndriver]

Another thing to try.


On the front of the shift you kind of have that bulge. Kind of curl your fingers under in and hold light pressure.

Can you feel grinding? If you've ever felt a bad bearing roll, you'll know what I mean.

If not, it's not as likely in the transmission.

 

[r3gulator3]

Sounds to me like a rear end problem. Most likely in the power divider. My brother had a similar issue, he chose to replace both rear ends as he had a million 6 on them.

I also had a similar problem with a 579. Eaton had a problem with thrust washer failure in the power divider. There was a service bulletin on it.