Rear end clunk

[rbbaker]

2002 Explorer, 4.6, with the ls rear end.

Just wondering if anyone else has encountered this issue and if so, were you able to rectify.

We have had the standard Explorer whine since forever and have learned to live with it. We also have a leak from the drivers side rear seal, again, able to live with, I just keep filling the diff. When the truck is driven around the city and on short highway trips all is well. The problem reared its ugly head the last couple of days after making some highway trips of of over 500km. It sounds good on the straightaways and corners on the highway. When we get to a town where we are making low speed turns we get a clunk, almost like something is binding up and then releasing. It is not constant, usualy just once, maybe twice during a turn and that is it. I am wondering if running for such a long time in a relativly straight line is causing the discs to lock together and then they snap apart when we are turning. Any help would be appreciate.

 

[imp]

2002 Explorer, 4.6, with the ls rear end.

Just wondering if anyone else has encountered this issue and if so, were you able to rectify.

We have had the standard Explorer whine since forever and have learned to live with it. We also have a leak from the drivers side rear seal, again, able to live with, I just keep filling the diff. When the truck is driven around the city and on short highway trips all is well. The problem reared its ugly head the last couple of days after making some highway trips of of over 500km. It sounds good on the straightaways and corners on the highway. When we get to a town where we are making low speed turns we get a clunk, almost like something is binding up and then releasing. It is not constant, usualy just once, maybe twice during a turn and that is it. I am wondering if running for such a long time in a relativly straight line is causing the discs to lock together and then they snap apart when we are turning. Any help would be appreciate.

A single clunk, or perhaps a few in succession, then none, are more likely to be caused by a rear wheel bearing, IMO. I had what I swore would be gear noise, which turned out to be a wheel bearing having a large pit in the rolling surface of the outer race.

The most certain way to diagnose location of noise generation is by running drive train with vehicle up on stands, wheels free of the ground. Use a stethoscope to carefully "sound" areas around the suspension knuckles, and wheel bearings, as well as the bottom of the pinion gear area and body of the center section. I pinpointed the noise in a wheel bearing, but could feel absolutely no hint of a fault in manipulating and rotating by hand. The gears were OK!

This procedure is not without risk and danger. It should be done only by someone very mechanically-experienced.

 

[rbbaker]

A single clunk, or perhaps a few in succession, then none, are more likely to be caused by a rear wheel bearing, IMO. I had what I swore would be gear noise, which turned out to be a wheel bearing having a large pit in the rolling surface of the outer race.

The most certain way to diagnose location of noise generation is by running drive train with vehicle up on stands, wheels free of the ground. Use a stethoscope to carefully "sound" areas around the suspension knuckles, and wheel bearings, as well as the bottom of the pinion gear area and body of the center section. I pinpointed the noise in a wheel bearing, but could feel absolutely no hint of a fault in manipulating and rotating by hand. The gears were OK!

This procedure is not without risk and danger. It should be done only by someone very mechanically-experienced.

Thanks Imp. I will prop it up onto stands and give it a listen. Hope that it is just wheel bearings.

 

[LMHmedchem]

Thanks Imp. I will prop it up onto stands and give it a listen. Hope that it is just wheel bearings.

Rear bearings are not expensive (~$50 for a good one), but they can be a pain to replace since the bearing and hub have to be pressed together into the knuckle. The last time I had one done it cost $400, not including the bearing. There was more work done than just the bearing but enough said that it is expensive. The shop I use doesn't have a hydraulic press so they had to send it out which increased the cost even more.

If you are doing it yourself, it is better to replace the entire knuckle assembly. You can get a quality part (SKF or Moog) from RockAuto for $175-$195 here in the US. I don't know what shipping would be to Canada. Replacing the entire knuckle is a reasonable job in the driveway but you would want to watch a video or so first.

LMHmedchem

 

[imp]

Rear bearings are not expensive (~$50 for a good one), but they can be a pain to replace since the bearing and hub have to be pressed together into the knuckle. The last time I had one done it cost $400, not including the bearing. There was more work done than just the bearing but enough said that it is expensive. The shop I use doesn't have a hydraulic press so they had to send it out which increased the cost even more.

If you are doing it yourself, it is better to replace the entire knuckle assembly. You can get a quality part (SKF or Moog) from RockAuto for $175-$195 here in the US. I don't know what shipping would be to Canada. Replacing the entire knuckle is a reasonable job in the driveway but you would want to watch a video or so first.

LMHmedchem

It should be kept in mind that replacing just a wheel bearing pretty much leaves the wheel alignment unchanged, a factor to consider with independent rear suspension. Replacement of the entire knuckle may affect alignment adversely, maybe enough to cause unacceptable tire wear, since various dimension tolerances on the new knuckle are introduced. Replacing just the bearing is definitely not a job for the "driveway" if a hydraulic press is unavailable along with a selection of various diameters of bushings with which to press bearings. I use my 3/4 inch socket wrenches, of which quite a few diameters are available. Some contenders have claimed they were able to hammer old bearings out and new ones in. Be wary of such claim; luck will likely have it once you remove the knuckles to do bearings, they will prove to be tight as hell and immovable by hammering. Good possibility of ruining the knuckle.

 

[BrooklynBay]

Harbor Freight has hydraulic presses, seal drivers, and C clamp style press tools. Check the universal joint on the driveshaft for wear.

 

[rbbaker]

Thanks for all the replys. Bit of an update. A couple of days ago the wife complained about the clunking again saying it is getting "irritating". I took if for a test drive and the clunk in now more of a bang and not just once in a while. It pretty much bangs quite constantly when turning corners and once in a while while driving straight. It almost feels like the truck is bucking and people on the sidewalk look because they can hear it.

I put all four corners up on jackstands and ran the vehicle and got the odd clunk. Pulled fuses a17 and 18 to disable the transfercase in case that was the issue (and so that I dont need all 4 wheels of the ground while testing). Took it for a test drive and it still bangs constantly going around corners. Listened to both sides and the diff with my stethescope and the only noise I heard was a bit of gear whine and the rubbing of the brakes.

Backs story, not sure if related but about 4000k (2500 miles) ago I replaced the intermediate servo before we went on a long trip. Ran like a dream the whole way (except for blowing out a spark plug and having to helicoil it on the side of the highway, but that is another story). Not sure if it could be the tranny since it primarily happens when cornering but you never know, this is why I am reaching out for help. HELP!!!