Clicking from front end + no 4wd. Disconnect or diff?

[MrSmithsTB]

I've got to crawl under the truck later today to check things out, but I have a fear that my front diff has shit the bed. Went out with Gordinho and mooseknuckle yesterday. Had a blast and everything seemed to be working fine. We were literally taking the last "puddle" before we got back to the street and I managed to land myself in a rut just too deep to power through. I got pulled out and took a different line through some slop. Stuck again! Switch to 4lo and still nothing. Someone noticed a clicking coming from the front end and advised me that my front wheels were not spinning. Pulled out a second time and ran through to the left of the ruts. Now I have a clicking coming from the front end, even when in 2wd. The tc still engages and locks the prop shaft. The actuator still seems to be working and the selector switch will show that it has changed, but only the rear wheels spin. Initially, I was thinking "ok, its long overdue to rebuild the disconnect anyway. Doing reading this morning tells me that the clicking could be indicative of broken gears in the housing, which would suck. There was no crash, boom, bang, of anything like that. I almost think I can recall hearing a rapid clicking as I changed from reverse to park while stuck, but I had the brakes applied and could just be looking for a something to blame. Wondering if anyone has any initial thoughts while I wait to check things out more thoroughly.

[MrSmithsTB]

Pulled off the fill plug, drained a little fluid and stuck my finger in the filler. Couldn't feel or see any chunks and I could not produce any metal shavings. In the daylight the fluid looks to have a very slight metallic tint, but only when it is pooled. Again, I could only be seeing that because I don't want to. I soaked some of the sample I took in to white paper towels and there was no tint or even small shavings, just a dirtier version of gear oil. Changed the fluid @ 20-25k miles ago and it is no more used-looking than expected. Not milky at all, so I know there is no water. Maybe I got hit with a double whammy and my disco and a u joint went at the same time? Maybe the 4x4 wasn't working to begin with and that was the only time I actually needed it yesterday? Not quite sure what else to look for before throwing parts at it.


Edit: There is some slight movement in the pass side CV where it enters the disco, and all of the boots are intact.

[MrSmithsTB]

Sorry for the triple posting!

Next round of tests.
Jack up pass wheel and rotate while in 2HI. Clicking noise present.

Switch to 4HI, noise present. Front prop shaft does not turn.

Keep in 4HI, lower pass wheel, raise d/s wheel. Rotate. Clicking noise present. (D'oh, forgot to check for prop shaft rotation!!)

Switch to 2HI, noise goes away.

So, since the noise comes only from the pass side while in 2HI, I am going to assume that the problem IS the disconnect. Both the actuator and the encoder motor are functioning properly, TC and diff fluid changes are up to date. Someone please feel free to add a different opinion. I would actually welcome the sage advice from a more seasoned individual. I will say, however, that I find the IFS to be a great help in diagnosing the problems, since it can be isolated to one side or the other.

[Trail X]

Sounds like disconnect, but it could possibly be other things.

Often, an indicator of a failed disconnect is that the tripod housing where it enters the disconnect will be loose. You can see this if you crawl under there, and force up with some muscle. The tripod shouldn't move much, but if it does, that could indicate the internal needle bearings went bye bye.

I'd put my money on the disconnect.

When you rotate the wheel... what is the frequency of the clicking? Is it once a rotation? or, say, 10 times per rotation?

[MrSmithsTB]

I just played with it a little more. I would say closer to 10 clicks per shaft rotation. Watching both shafts while turning the wheels, there is definitely playing on the pass side, none on the driver side. I can see it jerking up and down.

There is no prop shaft movement from the d/s when in 4HI, but there is when in 2HI. Also, when either switching from 4HI or after rotating the p/s wheel, the noise is present on the d/s for a few revolutions and the prop shaft stutters briefly before everything smooths out and the noise goes away. Prop shaft does rotate in 2HI with the rotation of the d/s wheel.

[Trail X]

Time to dig into the disconnect.

[MrSmithsTB]

I would rather do that than remove the front diff any day of the week.

[MrSmithsTB]

Well, I got what I thought was an entire spare assy for $50, to find out that it is only the outer half. However, the bearings and the fork are good, so I only need to replace the seal in order to make it useable. With that, I decided to tear into my disconnect to see exactly what is broken. It decided to be stuck in the oil pan. Rather than become a statistic, I figured it best to leave it on the vehicle and service it as it is. Fork is broken and outer bearings seized, there was water inside from the failed seal. I put it back together and left the CV off. Dealer has the outer seal in stock, so I am going to pick it up this week and should have it up and running Saturday morning. Made out pretty good, so I don't have to pull too much from the tires/armor fund I have going.

[Trail X]

Glad it's working out so far for you.

Were the new bearings in good shape? Strange that they sold only the outer half.

Did you check your internal thrust washer? Some of those can get worn pretty good and cause excess slack in the system. Might be worth replacing it if it's worn.

[MrSmithsTB]

Glad it's working out so far for you.

Were the new bearings in good shape? Strange that they sold only the outer half.

Did you check your internal thrust washer? Some of those can get worn pretty good and cause excess slack in the system. Might be worth replacing it if it's worn.

Yep, bearings are almost new looking and free spinning. I have disassembled it and mine and have determined that all of the parts needed are intact and in very good shape. This was a local vehicle that was totalled. I had the owner pull the disco before he sold the motor. I guess he thought he got the whole thing, not realizing it was half stuck. By the time I picked it up, the motor was gone already. But for the price, I made out pretty well. Will be very happy to have 4wd again.