Grinding in rear end...

hshawn31 · #1 02-16-2008, 12:06 PM

i have a grinding sound in the rear of my 1995 roadeo 3.6l 4x4....it does it while backing up, and worse while driving. when you let off the accelerator, it makes a sort of whining sound and goes back to the grinding. i checked the brakes and they're fine. Is the rear end low on fluid? ( i hope!) i lubed the driveshaft and brakes and everything else and still the grinding is there.

FL 3.2L · #2 02-16-2008, 02:40 PM

I'd get a couple of quarts of gear fluid a new gasket, some gasket shellac, and pop the cover off the pumpkin and have a look.

hshawn31 · #3 02-16-2008, 11:21 PM

how hard is that?

hshawn31 · #4 02-16-2008, 11:22 PM

by the way, the gasket WAS leaking about a month ago, then it stopped. last week i used my 4x4 just about everyday, so maybe the fluid got used up an/or leaked out?!

Ramblin Fever · #5 02-17-2008, 12:12 AM

Sounds like it ran out of fluid, thus the leaking stopped.

Hate to say this, but you may be looking for a new rear-end if it was ran completely dry your gears are probably shot.

FL 3.2L · #6 02-17-2008, 05:27 PM

It'll take a couple hours if it's your first time. Be careful with the brake line on the cover. Remove all but the top most bolt with a catch basin and newspaper underneath. Loosen the top bolt. Crack the cover off and let the fluid drain. Take the cover off. Clean everything up. Put the cover on with a new gasket. Torque the bolts properly. Refill. Hopefully that does it for you. Post some pics of the innards.

hshawn31 · #7 02-17-2008, 08:07 PM

UPDATE: well, i decided to buy some fluid and fill it up just to see if it was indeed the differential. it took me an hour to get the fill/check bolt out, and when i did, sure enough it was low and maybe even out. i stuck my little finger in the hole as far down as i could and no fluid. I put in about 1qt and a half ( by the way those big fluid bottles are stupid...pita to fill the pumpkin with such huge bottles ) i cleaned everything up and just got back form a test run.

"grinding" sound did deminish ALOT, but is still there. I can mainly tell at lower speeds and when the tranny is downshifting. ( rodeo shifts fine, i made sure of that ) Its also very noticeable as soon as i let off the accelerator. So, is it something else, or are the gears f'ed? The grinding sound is very similar to spent brake pads on the rotors....

thanks for your help guys!!

FL 3.2L · #8 02-17-2008, 08:27 PM

You'll have to peak, but it doesn't sound good. You really should pop the cover and clean any debris out of there. Any chance water got in there while offroad?

Gizmo42 · #9 02-17-2008, 11:03 PM

Since you ran it dry you can pretty much bet the LSD is toast if yours has it (look for G80 on the options plate on the firewall). And a pretty good bet the bearings arent in very good shape either as well as the gears.

Ramblin Fever · #10 02-18-2008, 01:11 AM

All else fails, if you're not able to open the pumpkin, get yourself a good suction pump, and go at it again....sucking the fluid out you just put in, and put more fresh fluid in there....do it again SOON. Like tomorrow, you need to get that debris out and away from the bearings/gears.

hshawn31 · #11 02-18-2008, 12:22 PM

i dont think water could have got in there. i used the 4x4 on the roads during snow storm. the rodeo is sitting idle and will. i'm gonna take the advise and open it up as soon as i can.

what do u joints sound like when they go bad?

Gizmo42 · #12 02-18-2008, 03:47 PM

Quote:

what do u joints sound like when they go bad?

They clunk and usually you get a vibration when driving.

hshawn31 · #13 02-19-2008, 10:20 AM

no vibrations....

hshawn31 · #14 02-19-2008, 10:22 AM

UPDATE 2: just opened up the pumpkin. alot easier than i thought...the oil was very dark gray colored with silver specs in it. i almost wanna think someone added that no leak crap...but no large metal pieces. the gears actually look good. i'm gonna let the oil drain for 24 hrs to get it all out before adding new.

also, i found where it could have been leaking. there's another seal where the drive shaft meets the pumpkin. thats where its leaking. Pinion seal?....

pinion seal leak??

Gizmo42 · #15 02-19-2008, 08:18 PM

Yup thats the pinion seal. Try wiggling the pinion and see if it has any movement, shouldnt feel any. With the noise you are getting it may be possible the pinion bearing is bad or the nut backed off.

Some tiny silver flakes is fairly normal especially if the oil has never been changed and there's alot of miles on it. Before closing it up and refilling, get a couple cans of brake cleaner and spray everything inside really good to clean out all the junk.

Kinda hard to see the shape of the carrier in the pic with all the sludge (and my monitor is kinda dark) but looks like an open carrier, not limited slip.

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