new purchase. Big mistake??

[schoop]

I am praying you guys and gals can help me understand and possibly guide me. I am a 30 year experienced auto mechanic but what im not is an experienced 2002 ford explorer limited, auto 4x4 mechanic. Bought this vehicle 5 days ago with what seemed to be a common howling rear wheel bearing,,,WRONG!!!! Every question i google about this brings me here to many unhappy owners of bad rear diffs. Will be surprised if i dont end up divorced over this purchase as it was replacement for my wife! It is a beautiful looking and running vehicle but WOW the noises that are now coming from the rear. It has a limited slip 373 with steady howl. Starting from a stop, the first noise you hear sounds just like worn out brake pads which then slowly and surely begins to hum and howl at higher speeds. Letting off throttle makes no difference. Inspected wheel bearing in all the common ways except to realize i cant just spin tires by lifting the rear in neutral. I found RR wheel bearing recently replaced and all e-brake shoes removed. I changed rear end lube with the purple 75w140 and added the motorcraft additive to it. Removed abs sensor and cleaned. Thats where i found the thin small metal shavings. Was about to remove driveshaft so that i could freely spin axle to feel all bearings. This is when i realized i could move pinion up and down with a large 1/16" -1/8" play. I stopped right there. I am convinced i have issues in differential. What im not sure of is wherher i have multiple issues or just one big one. Seems when driving and i slow to make a turn it has made big pop noise and felt like it shifted vehicle sideways!! Same popping also seems to happen when backing up and turning also!? Other symptom seems to be if make a u-turn using shoulder of road it seems to lock into 4x4 but then stays in until a complete stop and park, or shut vehicle off and go again!! Can someone please elaborate on some of this or send me a link of exactly what i am to expect from these auto 4x4's please!?? I will be checking here frequently to answer any questions or look for answers. Hoping to here from those who like to right these wrongs as i can do the work. Googling just sends me to the haters of these. Also is there anyway to know if these things have automatically locked other than the feel???? There are no lights that i can see to tell you! Help!!!!

 

[TechGuru]

I am praying you guys and gals can help me understand and possibly guide me. I am a 30 year experienced auto mechanic but what im not is an experienced 2002 ford explorer limited, auto 4x4 mechanic. Bought this vehicle 5 days ago with what seemed to be a common howling rear wheel bearing,,,WRONG!!!! Every question i google about this brings me here to many unhappy owners of bad rear diffs. Will be surprised if i dont end up divorced over this purchase as it was replacement for my wife! It is a beautiful looking and running vehicle but WOW the noises that are now coming from the rear. It has a limited slip 373 with steady howl. Starting from a stop, the first noise you hear sounds just like worn out brake pads which then slowly and surely begins to hum and howl at higher speeds. Letting off throttle makes no difference. Inspected wheel bearing in all the common ways except to realize i cant just spin tires by lifting the rear in neutral. I found RR wheel bearing recently replaced and all e-brake shoes removed. I changed rear end lube with the purple 75w140 and added the motorcraft additive to it. Removed abs sensor and cleaned. Thats where i found the thin small metal shavings. Was about to remove driveshaft so that i could freely spin axle to feel all bearings. This is when i realized i could move pinion up and down with a large 1/16" -1/8" play. I stopped right there. I am convinced i have issues in differential. What im not sure of is wherher i have multiple issues or just one big one. Seems when driving and i slow to make a turn it has made big pop noise and felt like it shifted vehicle sideways!! Same popping also seems to happen when backing up and turning also!? Other symptom seems to be if make a u-turn using shoulder of road it seems to lock into 4x4 but then stays in until a complete stop and park, or shut vehicle off and go again!! Can someone please elaborate on some of this or send me a link of exactly what i am to expect from these auto 4x4's please!?? I will be checking here frequently to answer any questions or look for answers. Hoping to here from those who like to right these wrongs as i can do the work. Googling just sends me to the haters of these. Also is there anyway to know if these things have automatically locked other than the feel???? There are no lights that i can see to tell you! Help!!!!

Look up the Brown Wire Mod which people use to add a switch to turn the auto 4x4 off, you could use a variation of this to add a LED indicator to let you know when the auto 4x4 enguages.

Sounds like your messed up differential is causing the 4x4 to engage which is quite possible since the rear speed sensor is on the differential. But the popping could also be the LSD breaking loose if someone neglected to put in Motorcraft Friction Modifier in the diff oil. but since you mention feeling like shifting sideways sounds more like the 4x4. If I drive in a circle on gravel with the 4x4 on it will pop as the drive train binds until the tires slip.

My rear diff has problems too but not as serious as yours. Mine is just loud and gets quieter if I let off the gas. I've put about 5000 miles on it like this and it does not seem to be getting any worse.

Be sure to clean the filler plug well as it's a magnet to catch shavings.

So do you want to rebuild the differential yourself or buy one ready to go?

http://zbag.com/440-1384d.html

Since you are a experienced mechanic I assume you have the ability and tools to rebuild the differential yourself.

Just get a Timken bearing kit and a new ring and pinon. Most of the time the LSD part does not need rebuilding.

Ring & Pinon: http://www.ebay.com/itm/171179716851

Bearing and Seal Kit: http://www.rockauto.com/en/moreinfo.php?pk=2472674

It's around $100 for a clutch plate kit, up to you if you feel it needs to be replaced.

Be sure to fix your parking brake, it's a inspection requirment here at least. Mine didn't work when I got it, the passenger side shoes were missing the pad material.

 

[schoop]

Thanks for your thoughts and the brown wire idea, Guru. I was fortunate to actually find another diff locally for 350. When i weigh the cost, btw thx for links, and time to rebuild it, guess im gonna put used one in this time.
Thinking a switch and led is a great idea....piece of mind anyway.

 

[TechGuru]

Thanks for your thoughts and the brown wire idea, Guru. I was fortunate to actually find another diff locally for 350. When i weigh the cost, btw thx for links, and time to rebuild it, guess im gonna put used one in this time.
Thinking a switch and led is a great idea....piece of mind anyway.

Thing is with used you could be buying one that's about to make a bunch of noise. It's a common problem. And you're saving what? By my calculations you're spending more that way unless you're needing to pay someone to do the labor of rebuilding the diff.

140 ish for the bearings and 160 for the ring and pinon...$300 ish

 

[anthonymtz]

Hey there guys, im wanting to get my rear diff rebuilt, I wanted to know dose anyone know of the "performance" parts for higher hp application's? I'm trying to get a 4.6 s/c engine built for the truck and I don't want to blow the diff out, maybe a different gear setup? I have 3.73's but I have the annoying whine, also the timing chain chatter in the mornings (cold starts) thanks!

 

[schoop]

My thinking is this...i can rebuild engines, troubleshoot problems and very competent mechanic. Until this winter i have always swapped transmissions but i finally rebuilt one and said no more swapping. I was successful and its way cheaper and nice to know what you have when done. I have not set up any rear ends yet but am confident i can do it. I saved the link on here taking you through each step for these. The place dont want the core so im thinking i will put used one in so she can use it for work and commuting and this will buy me time to rebuild this one as my first differential setup. I also have 81 z28 im restoring that needs same so im thinking its good time to conquer this area. More money but i can spread it out over time as the explorer is new to us. They are giving me a 90 day guarantee on the diff so it will then only be my labor vested. I agree with you though about rebuilding because id rather know whats in it.
What is the cause of this problem for all these to be so bad???