06 F-250 6.0 Groan

[goggiano]

Good afternoon,

I've done my best to search through the threads on this topic but have not found anything conclusive. Currently I have a bit over 30k miles on the truck and am experiencing a wierd "groaning" when I pull into my driveway at a slight incline and then shift to neutral. I can recreate the noise by keeping my foot on the brake and shifting from drive to neutral and back again. This doesn't happen at all when I stop at a regular stop or while I am driving normally. Any ideas?

Thanks!

[goggiano]

This "groan" occurs about half of the time even during regular driving...It lasts for a second or two at the most.