I've got a scrubbing noise at very slow speeds (5-15 mph).

It's coming from the front of the truck and I can feel it a tiny bit in the steering wheel.

It doesn't change when I turn in either direction or press the brakes.

I also have a hum and very slight vibration at around 70 mph.

I pulled the front shaft and the slow speed noise continued, but the high speed noise stopped.

I jacked up each front wheel, put the transfer case in N, and spun each wheel by hand. I heard a the noise no matter which wheel I spun, but couldn't successfully locate it.

I'm thinking the diff is failing, but is it a bearing or the gears themselves? When I changed the fluid a year ago, it had metal shavings in it.

If it is the diff, how likely is a catastrophic failure? I'm planning a 1400 mile road trip next week.

 

Hi Dr M,

Diffs usually deteriorate progressively and make the most noise, usually, on overrun. They rarely fail catastrophically but it's been known to happen when they are really worn or defective and a piece of bearing or a broken helical tooth jams between the pinion and crownwheel. I've only known of one major failure in 40+ years on an LR where it went 'bang' big time and cracked the cage completely but this is rare.

The later diffs are more prone to failure typically the LR3 but I believe it isn't overly common.

Sorry I can't be of more help as this is such a rare occurence.

 

Mine failed, I was on the highway and heard a crunching/grinding noise which was intermittent. Was in New Hampshire so I got it towed to a local shop. Mechanic first thought it sounded/felt like a stuck brake he said. Turned out to be the front diff.

Was able to get it towed to Cityside (AAA+ rules) and they replaced it, but I recall they said they don't see diffs failing much. I can say it was much more obvious than what you describe - it was a sound that made me stop driving right away.

 

Feel the pumpkin after you drive it, if its hot, its the diff.

 

Should have dealt with it when you found metal shaving on your last fluid change.
Drain the fluid, what color is it, does it smell burnt and what about checks of metal on the magnet?

 

At least salvage diffs are cheap.
When my front one went it was a couple loud cracks and pops...

If it implodes you would prolly be able to lock it and get to where you are headed. Done that a couple times

 

The diff definitely gets hot when driving. As in, touch it and get burned. I didn't know that was a symptom of diff failure.

I'll have to do this when I get back. As I recall from a year ago, there were no chunks but there was plenty of ground up metal.

I already pulled the front shaft to diagnose it, so I'm hoping that will reduce the stress on the system until I can swap it.

Thanks for the help, fellas!

 

If it turns out you need a diff let me know. I have plenty.

 

Your pumpkin will be hot to the touch if your diff is bad, because a bad bearing will create a lot of friction. I've had to front diff failures; one I sheared 4 teeth off the ring gear and one I had a vibrating driveshaft. The job isn't hard, its just labor intensive.


Also, fwiw, I found a front diff for 70$ shipped with a 3month warranty here from Marty, it came in a bucket, it was dirty (I had to flush it out a few times), but after I cleaned it its working fine now.

 

yep they usually come, fully lubed (nasty). $60-$70 with shipping is what I have paid on a couple of occasions. if your 1400 miles brings you buy my place, you can get one for $2.75, $5.50 with bucket.