Loud banging noise coming from my front pumpkin

In continuation of my other thread...

Out doing some wheeling the other night, went over a big bump/hill in the road, turned around, came back over it again.

I how have a loud noise coming from my pumpkin. It's a banging noise that increases with speed. If you place your hand on the differential cover you can feel the banging pulse.

It's a 96 XJ RE long arm 5.5" lift. Front diff is a Dana 30 with 4.56 gears and an ARB air locker. Stock steering and running a 33" tire.

Any idea what's making the noise before I pull the cover plate?

pull the cover... sounds like you crapped some teeth or something. did your locker engage while it was "banging"?

Locker was not engaged. Bangs in 2wd and 4hi

256offroad said:

pull the cover... sounds like you crapped some teeth or something. did your locker engage while it was "banging"?

Click to expand...

If its banging and you can actually feel it hit the cover, there is only one way to fix it, and it will involve removing the cover to see why.

Same thing happened to me. I also have a dana 30 with 4.56 gears, ARB, and at the time 33inch tires. I will put money on it being a snapped cross pin for the spider gears.

If you have the older generation ARB "the RD30" the cross pin has machined grooves for gear oil to get into and lubricate the spider gears. The grooves were machined too deep and cause a weak spot that will eventually crack. The cross pin also only has 1 retaining pin holding it in so if the cross pin snaps one end can come loose and then hit your pinion everytime it roates around. Pretty shitty!



You can see in the picture that one end of my snapped cross shaft is chewed up from hitting the pinion. You will also want to check the ARB carrier where the cross shaft goes through it, I bet the holes are egged out as well. If it hit your pinion I bet the ends of the theeth are a little chewed up as well but probably not that bad.

The new dana 30 ARB air locker, "the RD100" has an upgraded cross pin with much shallower cut oil grooves. It also has a retaining pin for each side so if it does break it does not backout and hit your pinion.

I would pull your diff cover and inspect before you do any driving!

If it is the cross shaft pin be sure to order another cross shaft retaining pin and two more o-ring seals while you are at it. The RD30 airlocker was designed for 2 cross sgaft retaining pins but for whatever reason they only drilled out the cross shaft for 1 retaining pin.

Here is the parts manual if you have the RD30 air locker, notice that in the picture it shows the cross shaft with much shallower cut oil grooves.
http://dedq15.mindfly.com/uploads/PDF/onlineManualsGuides/2-RD30.pdf

Pull the cover and youll see the broke parts of what ever is broke.

I broke 5 consecutive teeth on my ring gear and I had a banging that increases with speed to a point, did it in 2wd and 4wd.

DONT DRIVE IT! If a broken piece gets lodged wrong you could lock up your front end.

i'm with everyone else. pull the cover. could be the cross pin, or maybe even spider gear teeth have bent. gears only work when they're shaped right. and misshapped gears make noises.