Tried a search for this and didn't really see the exact issue anywhere. This all just started last night.

Went to back up and it felt like I ran over something or bumped something. I got out and saw nothing so put it back in reverse and it did it again. The truck moves but it seems hesitant and then there's a slight little "bump". It still moves, but not like normal.

I drove on the highway all the way home with no issues with the forward gears.

When i left for work this morning, same thing when I tried backing out of my parking spot. I'm going to check the fluid after work after it's warmed up.

Anyone have this? I'm worried about blowing the whole tranny or rear end.

I did have the rear pinion seal replaced earlier this year. Maybe I'm low on rear diff fluid?

Ugh, I just see dollar signs flying out of my pocket haha.

Trucks an '04 FX4 with about 91,700 miles on it. I've had it since '05 and haven't changed the fluid at all in the trans.

What's the worst case scenario here?

Thanks guys/gals.