Yep, front diff blew out. Real bad. Took off the front drive shaft in a parking lot. What’s the fastest we can go with the CDL engaged running off just the rear?

 

Not sure but 20-30 mph.

 

Good time to put in a locker or something similar

 

You can run any speed with the front driveshaft out and CDL engaged, won't hurt anything. Ran around with mine that way a couple days. Bunch of people have. I know of one guy who ran his full time that way for MPG gains cause it was just a street vehicle.

 

How bad is bad?
If pinion or ring gear break or even carrier failure & you’ve got pieces in there - then they’re liable to bind; and in that case you’ve got potential “explosion”

can you establish if you’ve got fluid & things move freely intact?

what happened?

 

did you develop a front wheel bearing problem at the same time as the diff? are you sure the axle shaft is seated/engaged in the diff?

 

If the driveshaft and drive axles are removed you can go any speed as long as you want. However it is very difficult ro get the axles out in the field, so as a practical matter, you are driving with a blow diff and no driveshaft. The axles are turning the diff and grinding whatever broke. Make sur its fi=ull of oil, go slow and stop as soon as you can as it may come apart at any moment.

The point if disassembly where you could remove the axles is the point where you could remove and replace the diff, Possible in the field, but hard. The biggest challenge is often separating the ball joints

 

Only took about 15 minutes to drop the front drive shaft (note to newb Disco owners, always carry tools)...

Anyway, to answer some of your other questions, I posted a lot about this earlier this week, so won't go super deep, but basically had a nasty screeching on decelerating. Not noticeable in town but very much so at speeds above 45-50. Anyway, it got bad enough to finally, on the freeway, to give a sudden CLUNK and then the sound of a very high pitch whine, which was the sound of teeth stripping against something. I have a new diff on the way already so I'll drop it and post photos.

And yes, I had a hub issue coincidentally with this diff issue.

So to end the saga. I dropped the front drive shaft in a parking lot and went on our way for another three hours home at normal highway speed. Drove great. SO thankful for having a CDL. Also thankful to have a truck that's so simple to work on in the middle of nowhere.