Did I damage the diffs?

just go get a full service done. Change every fluid grease every fitting. If you have a hydraulic clutch you could flush that as well. I don't know what the interval is on a freightliner. On my paccar it's almost never

 

I got my truck at 460,000 I am now at 550,000. When I first got my truck I checked the fluids and they were all brand new I probably won't do anything but oil changes for at least another 200,000 miles

except greasing I try to do that every other month

 

Next time you check the fluid. Look at the color. Mines got over 700k still looks new. Factory warranties are 750k with synthetic fluid in them. They do get neglected. I’ve only changed mine once at around 1.4 mil. Rears still good. The main thing is to never let them spin. If they start spinning in a hole, or steep dock, driveway. Hit the brake, engage, them. Never engage while spinning. Get through the uneven terrain and disengage. I rarely use mine. Always engage and disengage while completely stopped, though not required. I’m extra carefull, sometimes older Trucks can get stuck, and need to be moved in reverse to disengage. Something to watch out for. Most differential failures are from abuse of some sort. Usually spinning. Doesn’t take much. I learned the hard way, when I first started Driving. Burned one up getting out of a icy dock.

 

Yea Freightshaker warranty on those is 750K miles.

 

2nd.

Didn’t hurt a thing. As long as you didn’t have a wheel spinning when engaged, nothing was damaged. Even on dry ground or making turns. Why? The power divider, engages the other drive axle. Both axles are still Open Differentials, not locked in. So, you’re safe. Happy motoring.

 

I know on my t680s the interlock automatically disengages around 45mph. Maybe the freight shakers do it too?

 

The only trucks I've been in that automatically disengage were trucks with full lockers

 

You need to get rid of whatever a Qualcomm is so you can see your dash.