Rear end noise

[devhawes]

I have a whineing sound that I think is coming from the rear differential on my 91 Explorer. I here it at all speeds when driving. I jacked up the rear end and put it in gear, throttled up to about 2000 rpm and I can hear it well so I no it is not tire noise (Tires only have 6000 miles on them anyway). The dif is a non traction lock. Only one wheel spins at 2000 rpm (jacked up). When I let off the gas I get a on/off grinding sound and I can see the stopped wheel trying to move. Took off the dif. cover and the ring and pinion gears look to be in excellent shape. The small gears in the dif. are marked up a bit but not excessive. Oil was dirty but no metal or anything.

How can I be sure if the problem is in the rear end? I would hate to change it for nothing. Any tips on pinpointing the problem?

Thanks
Devin

 

[ExplorerEddie]

I don't know much about this but I can share my experience...I got my oil changed at a in and out shop and they checked my rear diff, but the plug or something came out a few hours later while driving and drained all my oil out from my gears. I ran it for a month without realizing it until I heard a whinning sound whenever I pushed on the gas, It started after 25mph and got worse as the speed increased. when I slowed down at low speeds I heard a awful grinding/ rubbing sound until I stopped. I brought it into a service center and they showed me how the gears were messed up. They told me that they had to replace all the gears and practically the whole rear axle because of the heat of running it for so long. It is costing me about $800 to fix and I don't get my X for a few days. I think its about time to learn how to change my own oil!! Anyways check the for sale section someone is selling a rear axle if you need it, a little too late for me though.
I hope my experience hellps

 

[BExplorer]

Alomost same

I to have a rear end noise, and I dont know if it is the drive shaft u-joint or the diff. When I push the gas it make a couic,couic,couic noise that follows the speed and it goes out at 30 mph(or it is to fast and I cant ear it anymore??). What should I check, and how do I check it?? I'm going to do my brakes, so might has well check into it before it breaks.

 

[ExplorerEddie]

I should have had it checked out right away because this could have been prevented, I just kept on putting it off until it made the noise, both of you should get it checked out quick.

 

[TDG]

BExplorer: Could be the motor mounts or the U-joints. Generally the drivers side motor mount will let loose first because it is on the tension side. The one on my 92 came off in several pieces when I went to change it and it had the same sound going through 1st gear, when then trans hit 2nd it would go away. The good news is that the drivers side motor mount is the easiest to change as long as you are a contortionist.

 

[devhawes]

I pulled off the dif cover and both axles. Everything looks in pretty good shape. The oil was pretty bad. I put it all back together with new oil. I think the noise maybe coming from somewhere else but I am not sure what to check next.

 

[LukeDog3D]

BExplorer: I believe it is your u-joints. I had the exact same symptoms as you describe. If its not that then I dunno, but I have a good 8.8 for sale if anyone is interested.

 

[o6tnineo]

i had a problem just like this, my 96 X would whine when i would accelerate, all the while getting more and more high pitched as i went faster, then while decelerateing it would really whine, i thought that it was my rear end too, well, it was and it wasn't, i took it to my dad's shop and put it up on a hoist and reached up and grabbed the drive shaft and could move it up, down, left, right, took the rear end plate off and everything looked great, only one thing it could be, the rear bearing, yep, it was beat to ****.

there is a front and rear bearing there between the axles and rear U-joint and let me tell you the front bearing looked alright but the rear one was scary to say the least

 

[drnaline]

Check the Axles

After running the truck up to temp. With your hand fell by the axle tubes for heat. if one side is hot and the other cool, your noise may be an axle bearing.

 

[ExplorerEddie]

I have to get the rack and pinion(???) fixed today, he already did the gears and crap but they had to order this part. he gave me a deal, grand total was only 735!!

 

[devhawes]

I have determined that the sound is definatley coming from the rear end. The gears look good and so do the outer axle bearing. I think it must be and inner axle bearing or pinion bearing. I guess I will look around for another rear end and just swap the whole thing.

 

[devhawes]

Turns out it is the pinion bearing. Anybody change one these?

 

[drnaline]

new rear

Yup, Some times if you catch it early you can just replace the bearing. Which bearing was it the inner or outer? How much sediment was in the gear oil? If the bearing or pinion is out did you have to nock it out or did it fall out?