Trying to Diagnose Bad Differential

It's got it's own oil drain plug pull it or open the front cover since you got it out.

 

Carriers are pretty tough, I agree, you probably puked the power divider.

 

With all 4 drive wheels on the ground, if something was broken in the rear rear axle, the inter axle driveshaft would spin. If only the input to the front diff is spinning, something is broken in the front diff. Likely a failed power divider section.

 

Your axle splines look like you could shave with them, scrap in my book. I would assume side gears in differential are worn too. Gear shop could inspect it for a fee. Found it is best to just go new these days if budget allows, cheaper in long run.

 

Soooooo what conclusion did you come too?

 

No. Whoever told you engaging the lockers while moving caused the failure is 100% wrong. If no tires are spinning or you're not driving around a curve everything is moving the same speed. Its when you've got a wheel end spinning faster than the rest (ie a spinning tire) and you engage the locker that you'll cause damage.

Never want to run the diff locks on hard ground in turns. Interaxle is generally fine to leave locked in when off pavement and shouldn't hurt anything making turns. Tire size is important new tires on 1 axle and worn on another will cause tire scrub and additional stress on the gears though. A lot of guys running off the pavement on loose ground or thru ruts and holes will leave the interaxle locked in.

 

Always best to lock them in before you are spinning or stuck.

 

Think of the damage caused to the side gears/spider gears when you spin a wheel. All that high speed spinning of the spider gears. Then the shock load when the spinning tire rapidly regains traction.

The interaxle lock is a blessing when you get into the big tridrives we run up here. One wheel loses contact with ground when driving through a hole and you're spun out.