I left home this morning for work. I noticed driving in the neighbor hood the bronco was running real rough. (like a flat tire) I got out on the main street and then all of the sudden my truck started shaking like crazy. The drive shaft felt like it only had one bolt holding it on and was clanking and poping and binding like it was going to twist off. (this is only how I can discribe what happen) I turned around and made it home and it just got worse and worse.

At lunch I crawled under the truck and it seems like it is the differential. I could not visualy see or shake and feel anything wrong with the drive shaft. I am just assuming. i could turn the drive shaft back and forth in netural just a little but it seems I heard the same typ of noise in the diff.

I know I need to jack the rear end up off the ground and turn my wheels to see if I can hear the noise in my dif. I am pretty sure I am going to hear and feel it?

I don't know anything about difs. Will I need to replace the whole thing, or can the difs be rebuilt while on the bronco? Tell me what kind of job I have in front of me. This is my daily driver so I need to fix this fast.

I was also thinking I could remove the drive shaft and drive on my front dif until I get the money to put it in the shop. Is this an Option?

I have posted this on the section "transmisions differentials etc" but have got no response.

Thanks
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This is just stuff I've heard, so let some other guys chime in before you take it as gospel, ok?

First, check all the u-joints to eliminate any problem there. Check your pinion nut. I've heard they can work themselves loose.

Put the truck up on stands and pull the rear cover and see what you can see. This is what I found when I pulled my cover:



You may of broke a side/spider gear (like above), which can be replaced easy enough if you prepare yourself for it. As long as the carrier didn't crack, and the ring/pinion set is ok, it's a DIY type job.

 

Got all the ear marks of a pinion nut come loose. The Pinion nut holds the pinion gear into the differential housing. It is buried behind the u-joint at the front of the differential. The u-joint will have to be removed to get at it. It can be tightened however, the only torque specs given for it that I am aware of are for initial installations which require a pre-load torque spec followed by a final spec once the pre-load has been achieved. I know this has been met with much discussion here in the past and there may be a consensus as to how to "re-tighten" a pinion nut without going through the entire installation process.

DO NOT assume that my "diagnosis" is correct here! My initial response is based upon only what you posted. Something like this bears close inspection and in-depth scrutiny.

As to the idea of driving around with only the front driveline in place, it can be done. HOWEVER, if the problem is not a u-joint or something OUTSIDE of the differential, you will just continue to damage the differential innards if you drag it around behind you because there is no way to disengage the differential from the wheels like the front axle.

 

I will speak from my experience (which was exactly the same as yours) and will take my guess at saying that either the pinion or ring (or both) lost a tooth and you will need to replace them. If what i say turns out to be right (i hope it isn't because this is a spendy repair), you have some options: replacing the pinion and ring (and probably the bearings and tone ring if it got hurt), to do so you will need a kit with a relation that matches the front differential (if you have 3.55 in the front, the rear has to be matched at 3.55 - 3.54 or you'll destroy your transfer case once you engage 4WD), other cheaper option would be replacing the whole axle with a similar unit from a junk yard (yet you have no way to be sure this one isn't already ready to fail, just check the internals and replace the gear oil).

 

Thanks you guys. I will tear into it this weekend. Wish me luck.