I was ask to put in a seal on the front input yoke on a trucks power dvider. I pulled the yoke thinking it didnt just start leaking because of a bad seal. I found some metal flakes behind the seal so i pulled the seal flange and the spider gears one was gone. I havent pulled the thirded member yet but wouldnt the driver have felt something?
The divider only really works when there's a difference in rpm between the front and rear axles, as in some wheel spin, otherwise it's just a slow movement if at all as the truck handles corners and such, or if there's a difference in tire size averaged out between front and back. The whole carrier unit rotates of course, but bad spider gears won't show up until they're pretty crunchy. Most drivers don't notice anything until the truck stops moving forward, if then.
He would only feel it if he was spinning without the power divider locked, and then he would have to be paying attention. That is asking a lot for most non owner drivers, and even for a good portion who do own it.
What you would feel would be a slight knocking feeling in the shift lever. I had a tandem dump truck that I babied for almost two month to finish the season. Kept the power divider locked in. When it gave out completely though, we had to pull it home. My experience with seals has been if they're leaking, something is causing it. Loose bearings, yoke, something is going to cause it. Especially the pinion seal on the rear driver of a tandem. If it starts leaking, could just as well order a diff.
I bet it could be felt when it broke the spider gear in to small pieces that could end up in the bottom of the rear end houseing.I end up with a reman diff.They havent had this truck very long it may have happend before they got it.