Rear Diff Grinding Noise. Car:GC8 '99 Turbo 2000.

CMX70

Member
Guys,

Seeking advice on the best course of action to repair the rear diff on my car

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Problem Description:
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Audible grinding noise from rear diff, it sounds like a bushing "type" noise to my untrained ear. It has a cadence to it with the rotation of the wheel. Local garage put the car on the lift and with the car in drive and wheels turning it is obvious that the noise it coming from the diff, hard to be specific but sounds like the front of the diff, where the drive shaft enters.

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Recent Repair History:
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19th June 2018: Near Side Rear wheel bearing worn, grinding audible when driving. Local Subaru garage replaced, the replacement was reported to be difficult, it was not possible to press the bushing from the hub, the driveshaft and hub were too badly corroded. I gave them permission to proceed with replacement of rear shaft, hub and bearing.


Q1. Ye guys know what spec rear diff is in my car?
Q2. Can the bearings be replaced independent of the diff? or must the whole assy be replaced?
Q3. Can a reliable rear diff be bought from a dismantlers yard or is the risk to high the diff will be moisture/water damaged?
Q4. What is the most economical approach, buy and replace the complete diff? or disassemble the existing diff, replace bad
components and reassemble & test? Would the garage man hours involved make this more expensive than a straight swap?
Q5. It is an unhappy coincidence that this failure follows soon after the N/S/R bearing/hub/driveshaft. What do ye guys think about
that? Did one thing lead to another?

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Car Spec
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Model: GC8KD3 Impreza Turbo 2000, Irish Model. .
Year: '99
ODO: 165K
Engine Mods: None


FYI:
Attached image of identification stamps on the underside of the diff. This stamp may mean something to somebody.

"814".... [unsure about this one, it's very faint, hard to read"
"8Z"
"KN9"



Thanks & Regards,
Ciaran20180727_200832.jpg
 

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Hard to tell without looking at the car . But did the grinding noise go away after wheel bearing was done .

i sounds like the Front propshaft bearing on the rear diff if your sure the noise is coming from there .
Cost wise would be cheaper swap the differ over unless you can do most of the work yourself
 
It was the spider gears in my diff that went. I got a spare diff with a different final drive and swapped the spider gears keeping my own crown and pinion. First step would be to pull the diff and see what the issue is - I have a good 4.11 crown and pinion if they are your problem, other than that you could just get a replacement diff - bear in mind that backlash etc need to be set correctly
 
Rear diff replaced, problem unchanged.

Guys,

A replacement diff was installed yesterday but the problem remains, I have the original diff on the bench at home and the movement by hand feels frictionless and smooth. What is the level of diagnostics required to be sure of the next steps? Is it basically using the human ear to track the source of the noise or is there further technical actions that can be performed to isolate the source of the grinding noise? The next proposed step is gearbox bearings swap, cost = 884.00 [replace clutch at same time]

Ciaran
 
Im after getting a grinding/scraping from the rear since changing rear discs pads handbrake shoes im putting it down to all bedding in!? Have any of these been replaced in yours lately?
 
Im after getting a grinding/scraping from the rear since changing rear discs pads handbrake shoes im putting it down to all bedding in!? Have any of these been replaced in yours lately?

Had the same, very common with aftermarket discs apparently, small lip that needs to be ground out - have a google on nasioc
 
Get it to a good garage who know what that are at ...probably save you in the long run
 
Yeah the handbrake shoe lip on the disc is rubbing the back plate , very common.
A specialist will usually offer to machine 2-3mm off for an extra fee .
It’s not dangerous but obviously needs doing
 
Yes.

We insist if we are fitting rear discs that allow approval fir rear disc lip to be machined.


If we are supplying only. We highly advise you get it done.

Let me know if we can be of help to you on sorting

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