Differential Rebuild or Used? 02 Explorer Limited

[jsmn4vu]

So when under load, different things are engaged inside the differential, which means the ring and pinion are moving, the clutches, etc. And that is NOT the case if coasting in Neutral?

The ring and pinion are always engaged and turning when the truck is in motion, whether in gear or in neutral.

 

[jpoprock]

Ok. So that means the WORST of the noise isn't likely my Ring and Pinion since it's worse when I am in gear and moving.

So what engages to make the noise that much louder and aggressive when I'm under load? He said if the Ring and pinion are toast, you'd be looking a lot of money and labor. I say... is it really all that big of a deal? A new ring and pinion isn't that expensive I don't think. So what makes that a big deal vs new bearings and spider gears. Doesn't it all have to come out anyway?

I'm trying to narrow down whether to have my mechanic rebuild the diff, fix what's bad in the diff, or put a used one in it. The scenario for under $1,000. I don't have time to hunt the nation for a rebuilt one really. The noise gets worse by the week.

And again, if I got 100K out of this repair, I'll be elated.
j

 

[jsmn4vu]

Even though the ring and pinion are always engaged, they can sound different when under load compared with no load (coasting).

The gears themselves are relatively cheap, but the cost of R&R (including correct adjustment of their engagement) can exceed the cost of a new diff from a salvage yard.

Correct setup of the gears is exacting, and not every mechanic is capable of doing it.

 

[sfbayjay]

Even though the ring and pinion are always engaged, they can sound different when under load compared with no load (coasting).

The gears themselves are relatively cheap, but the cost of R&R (including correct adjustment of their engagement) can exceed the cost of a new diff from a salvage yard.

Correct setup of the gears is exacting, and not every mechanic is capable of doing it.

Yes - what he said. Several shops I spoke with wouldn't even offer to replace the ring and pinion - said it was too difficult/risky to get them set correctly. Even some of my local Ford dealers wouldn't do it - their policy was to replace the entire differential assembly, complete with housing, to avoid having to setup the gears.

There are a lot of things that can cause noise in the back of your Ex. If you are hearing noises when you're coasting, my experience tells me that it's something other than the ring and pinion gears, which seem to only make noise when the truck is under load. Possible culprits within the diff are side (carrier) bearings and/or pinion bearing. Clutch pack (also inside the diff) typically makes noises when you're cornering, esp at slow speeds - something like pulling out of a parking space and making a hard turn to the side at the same time.

Beyond that, if you're hearing scraping noises when you're coasting, could be brakes sticking (I've had that problem). For me this was due to horribly corroded steel slides where the pads meet the caliper assembly - basically the pads were rusted in position. Or maybe e-brake shoes delaminated and grinding themselves apart inside your rear brake rotors (very common problem).

The noise you hear when the truck is under load (whining that starts with your foot on the gas and then stops with your foot off the gas) is very likely to be worn ring/pinion gears, so it sounds like you've got that happening. As I said before - I've had this issue for about 50,000 miles and I don't have any problems other than the noise - but I DID have all the bearings replaced.

If your mech is good and you trust him, you should trust him. His opinion is that you need diff bearings - probably he can tell if he runs the truck in gear while it's on a lift - you'd likely be able to hear the carrier bearings grinding away using a mechanic's stethoscope.

 

[jpoprock]

I found a used diff with 93K on it from a 2003, but it has ABS on it. I could have sworn my ABS cables were on the hubs, so I need to check. It would have a 30day warranty. I would have to think that I could get another 60K on that diff easy. That's all I really need since I drive about 20K a year.

I decided to stop driving the vehicle because it seems to be getting much much worse. It sounds like a semi roaring down the road, and it's hard to talk over because it's so loud. I was able to record it with my phone from inside the truck!

I know that crickly sound of when you're holding a speed. that's been around a long time. But this sounds like a really tight gear with no lubrication... and I know my diff case has oil (and metal) in it. I'm thinking the clutches are bad and maybe I've thrown teeth on the gears. That's what is causing the roaring vibration.

Another oddity is that if I feather the throttle just right, I can get it stay quiet for just a second or two. That to me is the most puzzling thing about it. If everything is always spinning, why does it stop for just a second when I let off the gas?

 

[dablack]

Another oddity is that if I feather the throttle just right, I can get it stay quiet for just a second or two. That to me is the most puzzling thing about it. If everything is always spinning, why does it stop for just a second when I let off the gas?

It isn't odd at all. When you go from a throttle on to a throttle off, you are changing what side of the teeth you are in contact with.

Lets say you have your foot on the gas. Friction from the road is trying to slow the ring gear down but the pinion is forcing that ring to turn. When you take your foot off, the friction in the drivetrain is trying to slow down the pinion but the ring gear (which is turning due to the motion of the wheels) keeps pushing that pinion to turn.

See? Simple.

 

[jpoprock]

AH yes... it is simple. I was completely forgetting about the friction working against the gear. You helped me visualize it, so thank you!

I just talked to my mechanic and he said once again that if it were him, he'd go with the USED diff. Though he's not afraid of rebuilding and setting a diff, he said that if I were pulling a boat or if the truck wasn't as old, he'd suggest a rebuild. But at this point he thinks a used diff would be fine. I have a 30day warranty, and he inspects them before he installs them anyway. He said it may or may not have a little whine, but I can live with that. My diff has been whining for YEARS anyway it seems.

There was some question about the ABS Sensor and if it was on the knuckles or the diff. I think it's on the diff. I looked at pix of my hub swap years ago, and there wasn't an ABS sensor present on either side. So it has to be on the diff case.

So it looks like i'll be getting a 2003 Diff with 93K miles on it for $350, and a little less than that for labor.

Final question: Does a transmission have moving parts that roar? I sure hope not! I don't want to mess with the tranny ever again. My fear is that the diff is shot and the tranny is somehow making noise as a result. I'm quite paranoid about things all the sudden, because everything hit at once.

He said I should have the front driver upper ball joint replaced, and the left rear tie rod end, and that would pretty much cover all of the obvious things that could leave me stranded.

Jason

 

[jpoprock]

Update: I hate it people don't follow up with their resolutions, so here is mine!
Bought a used diff with 93k miles for $350. Installed for $250. My old diff had a blown pinion bearing with tons of backlash. There weren't any missing teeth from any of the gears, but the wear pattern wasn't good. By the time I had new bearings installed, etc I could be every bit into it for $600.

My new diff hums a little at about 60mph, but I don't think that's uncommon. My mechanic said if it doesn't quiet down we could try a fluid change and more additive, but I don't see that as helping. Said it could just be the nature of the clutch plate design.

Honestly, I've had this veh since 19k and have 227k on it now... and it's always had a little chatter. It's quieter now then I can remember! New hubs, rotors, brakes, diff... I think I'm good for another 75k at least! I can I only hope anyway.

Thanks for the advise!

Jason

 

[5whiskey]

Thanks for your post and resolution update jpoprock. I just purchased an '02 that has a LS differential. When I test drove it all was well. I crawled up under it and checked tranny, motor, and transfer case for leaks. I didn't find any. I've heard some "chatter" when I start out making a sharp turn today (only put about 100 miles on the truck). I looked and noticed there is a lot of old caked up oil on the rear end. I think the pinion seal may be gone and the chatter I'm getting is from the differential fluid being low or someone added some without using the friction additive. Either way, I'm hoping I can replace the pinion seal and throw some fresh fluid in there and all will be well. It may be shot from previous abuse, but I hope not. If it is, I'm probably going to go with a used differential plus a self install. Good post and follow-up though.

I've done some reading and I believe the drive train past the motor in these explorers are a little on the week side. I was aware that 3rd gen explorers tend to have tranny problems, but I didn't know that the rear end was an issue. Oh well. The beauty of having an explorer is the fact that I can go to LKQ and there are rows and rows of them, probably a hundred or so, and used parts are plentiful. Even if there were some issues with them it's pretty easy to get parts on the cheap.

 

[Sock Puppet]

I've done some reading and I believe the drive train past the motor in these explorers are a little on the week side. I was aware that 3rd gen explorers tend to have tranny problems, but I didn't know that the rear end was an issue.

There are issues with every vehicle; you simply may not be aware of them until you either own one, or really research them. A guy could drive himself crazy worrying about "weak links" or "possible failure items", or you can enjoy the vehicle and address the issues when they come. The internet is great for many, many things, but one of the negatives is all of the bad things you can read about any particular item, and how it can convince you anything is a piece of junk.

 

[jpoprock]

There are issues with every vehicle; you simply may not be aware of them until you either own one, or really research them. A guy could drive himself crazy worrying about "weak links" or "possible failure items", or you can enjoy the vehicle and address the issues when they come. The internet is great for many, many things, but one of the negatives is all of the bad things you can read about any particular item, and how it can convince you anything is a piece of junk.

Yes, that is so true. You can't always predict what will happen with a vehicle. I'm not worried about much going wrong my vehicle anymore. Heck, it's got 225K miles on it. Why wouldn't i need to replace the upper ball joints, or whatever? Things wear out.

My left passenger window has somehow come out of the motor that lifts it, but the motor still works. There is a thread on how to do that, I know. I would also like to see about replacing the door seals because i hear a lot of air coming in (like the door is ajar slightly). I'm sure there is a thread for that too. Little things like that would make my truck seem as good as it was when I brought it home (except the paint job is a little worn in spots).

This forum has saved my butt many many times. You guys are all just fantastic!

Jason

 

[Kathryn barry]

If you at least install new bearing in the diff it will quiet it up a bit. The carrier bearings wear really bad for some reason.

I have (2) 3.55 open diffs if your interested in a used one. One with 143k and one with no cover w/60k, send me a pm if interested.

Hello was reading your comments do you still have rear diff 02 explorer