Author Topic: PLEASE HELP!! Rear differential noise....  (Read 2422 times)

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  • Offline Rock Master
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PLEASE HELP!! Rear differential noise....
« on: Jun 08, 2005, 08:06:35 PM »
To let everyone know before I explain the problem, my Toyota has the original '80 rear axle with 5.29 gears and a Detroit Locker, and has always worked flawlessly until today. Anyway, I was driving home today, on the Interstate doing about 60 mph, nothing out of the ordinary....when my rear differential started to sound pretty bad. The noise is coming from the pinion up near the companion flange and rear drive shaft flange. Then, later, the pinion seal went out, because I've got 80W90 covering the entire back end. Don't be confused though, the noise was there long before the gear oil started dumping, so this noise is not a result of having a low fluid level in the diff.

The noise will NOT happen when I have my foot on the gas, so when there's torque on the pinion it sounds perfect, but the minute I let off the gas, put in the clutch, or am basically coasting or slowing down, it sounds like the whole 3rd member is gonna fall apart. I cannot get it to make the noise in reverse, whether on the gas or off of it. When full-on braking, for say, a sudden stoplight, the pinion is even more noisy and almost starts to ratchet or act like it's getting stuck. I can not only hear, but SEE the entire process in action, because I have no bed, and only a tube cage welded to the frame, so I can look out my rear cab window and down at the diff.

Doesn't this seem like a bad pinion oil seal and a worn pinion bearing to you guys??? I believe this to be true, because of the fact that it is noisy ONLY when off the gas or in neutral. I want some feedback and/or 2nd opinions. Also, I know there are two pinion bearings, the front bearing and the rear bearing (inside the carrier). Would I have to replace both??? If it does turn out to be the oil seal and bearings, I don't have any pullers, anybody who might be in Denver, Colorado want to help me out, or get PAID to do this project for me?? My time is SO limited, I don't even know when i'll be able to get to it. PLEASE HELP!


  • Offline 4WD Legend
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Re: PLEASE HELP!! Rear differential noise....
« Reply #1 on: Jun 08, 2005, 11:48:06 PM »
yep, sounds like bearings.
i had a similar problem in the past and bearings cured it.
hold this. . .


  • Offline The 2K Group
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Re: PLEASE HELP!! Rear differential noise....
« Reply #2 on: Jun 09, 2005, 12:15:25 AM »
sounds like a loose pinion nut,,,letting the pinion walk in and out,,would explain the gear oil...could just be a pinion bearing let loose also..start by pulling the drive line off the rear yolk and see if the nut is tight..if not tight,,pull the diff,you have carnage..
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Re: PLEASE HELP!! Rear differential noise....
« Reply #3 on: Jun 09, 2005, 02:22:33 AM »
Or your $500 paper weight detroit let go and it ratcheting uncontrolably.  Pull the driveline and check for loose parts.  Remember that wonderfull detroit has 1/4 turn of backlash built into it so dont be alarmed if it turns about that far before there is any tension against it.
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Re: PLEASE HELP!! Rear differential noise....
« Reply #4 on: Jun 09, 2005, 07:13:00 AM »
I gave you a point to cheer you up!   :thumbs:

Auto problems are a bummer.  Hopefully you get rolling again soon.   :driving:
1989 4Runner: Dual Ultimate (Inchworm front & Marlin 4.70 rear), Marlin Twin Stick, 1200-lb clutch, 4.88 R&P, Aussie Front, Detroit rear, 30-spline Longs, Long hub gears, ARP hub and knuckle studs & 35x12.50 Cooper STT PRO tires.  Marlin rear bumper & sliders.  FROR front bumper.  SAS with Alcan springs & Rancho 9000XL shocks.  Budbuilt Bolt-on traction bar.  Custom Interior Cage by Those Guys Rod and Customs.

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  • Offline The 1K Club
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Re: PLEASE HELP!! Rear differential noise....
« Reply #5 on: Jun 09, 2005, 09:05:49 AM »
It's also possible you have broken pinion teeth.I have had this happen before and the only time it would make a noise is when i let off the gas and was coasting.Whatever the problem is,sounds like it's time for a rebuild.
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Re: PLEASE HELP!! Rear differential noise....
« Reply #6 on: Jun 09, 2005, 05:28:40 PM »
Loose pinion nut/crush sleeve, when you are under power it lifts the pinion up when you let off the gas the pinion drops and rubs/drags on your locker housing. Get a new crush sleeve and pinion nut and it should fix the problem. Might as well do the bearing while your at it that constant movement will/may mess it up. 
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