Rear Main Diff Bush Replacement Cost - Through Ford?

[SavageF6]

Keep us posted Mal

[Power]

How much for the cover Mal?

Edited 07/10/07 12:55 PM by Power

[South]

I have a clunk in my rear end, it only happens when the rear articulates slightly when im reversing off my driveway, then it clunks back into position when I drive off. I dont hear it again until the above is repeated.

Do I have the dreaded rooted bush?

[Full Monty]

The cover cost me $298 from Mal Wood, plus $25 to overnight courier it to me.

Its been a week now since installed, I was under the rear of the car last night to install a new swaybar linkage (bush was worn out causing it to rattle). So had a good look at it all with the torch, certainly a nicely fabricated peice of gear.

The only downside to the Fulcrum Bush is slightly more diff whine is transmitted, I mean negligable and only noticable at 100 - 110kph. Caused by the bush being firmer than standard.

My guess this is why ford went for the soft rubber bushes to prevent NVH, but to have to replace them every 2-3 years at a cost of $600 is a joke. Im happy mine is done and wont have to be done again for the life of the car.

If anyone wants an as new diff cover (standard) let me know (has done approx 5,000 km).

Its easy to tell if your rear main bush is rooted, apart from excessive clunks from the rear end, hop under the rear of the car (from side is easiest, behind rear wheel) and have a look at the back of the Diff where it bolts to the subframe, check the large Rubber Bushing surrounding this bolt, it may show signs of wear and tear, mine was sagging a little, and had a large split under the centre metal sleeve.

Side bushes were replaced also, but generally not necessary, mine were fine, but for an extra $20 each it was worth doing them for peice of mind.

[MUZ580]

What are the symptoms of a broken diff bush? Mine rear end is making a terrible banging and clunking noise when I engage first or reverse. I'm too scared to drive it incase I lose the rear end.

[senna_T]

get someone to have a look at it, generally it will clunk back and forth kind of like driveline shunt but louder (as I've experienced it)

[XR06T]

I got my car on stands, engaged the handbrake, and tried to let the clutch out in gear. my dad was under the car and you can actually see the diff moving and clunking as it takes up the load.

another thing, I have noticed that the big rubber bush that is between the rear of the gear box and the tailshaft has a nice crack in it. anyone ever had to replace one of these? could be causing clunks. I think that the centre of the diff also has a hand in the clunks, as with the car on ramps, you can turn the tailshaft and replicate the clunks. mine has a bit of play in it and I assume so does everyone elses..

Edited 15/10/07 05:43 AM by XR06T

[senna_T]

I've done the rear coupling on mine, but it was under warranty so I can't help you with a cost, I don't hear much about it though

[MUZ580]

Just had mine replaced - cost $900 which included a diff housing.

[Full Monty]

Ok, after a few weeks of having the aftermarket polyurethane diff bush installed, I am not happy with the amount of noise and vibration it transmits into the cabin. My Diff is quite new, and is still breaking in, before I could just notice the diff whine at 100 - 110.

Now it is more noticable, and at lower speeds. (can hear is as low as 65kph, periodically through to 80, then dissapears until 100kph and rises in amplitude and frequency from there on (havent tested over 120).

I am considering going back to a std Ford bush, as the softer compliance of the bush is obviously masking the majority of the noise.

I have spoken to a number of Diff builders, they all say there is nothing that can be done with the Dana m86 due to the curved gear teeth, they all seem to have periodic whine at certain ranges. Which seems evident by the amount of people going through new diffs under warranty, to no avail. There is only so much that can be done with the backlash adjustment, as the centre contact of the gear teeth is whats most important, and the deciding factor in the final setup.

so all in all, if your car exhibits any noticable diff whine with the standard bush, this will be amplified twofold with the firmer polyurethane bush.

=(

Edited 01/11/07 10:34 PM by Full Monty