Author Topic: blown diff  (Read 881 times)

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Offline jack67fb

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  • Location: WA
  • Car: 1967 GT S code fastback
blown diff
« on: May 17, 2019, 08:23:58 PM »
Lovely day today so thought I would take the 67 out for a run. Out in the country about 60 mph, BANG..bang bang.....immediate pull over no doubt something significant wrong.Checked suspension etc nothing wrong there, engine fine, still got all the gears.Noise coming from the rear, wheels/brakes all seem ok.Limped home 15km at 20mph.Seems like my diff is in trouble, and my 67 fastback has castings which indicate original motor, gearbox and diff.I have the 9" 3.25 lsd.
How do I best tackle this while keeping my car as original as possible?
I'm not looking for the cheapest way out , or to "improve" my diff, I want to get it back to where it was in 67.
Pull it out and take it to where ???? for a rebuild?(I'm in WA)
Any help much appreciated.
67 gt fastback s code
16 gt fastback

Offline trav68

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Re: blown diff
« Reply #1 on: May 17, 2019, 11:10:47 PM »
Dont want to do yourself? Not rocket science. If I was paying someone in Perth see Phil @ Final Drive.

Have you jacked up and checked driveshaft etc to isolate to diff internals?

Rebuild of internals ( bearings, gears, lsd) wont be outwardly visible



Offline barnett468

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  • Posts: 6795
Re: blown diff
« Reply #2 on: May 18, 2019, 12:28:35 AM »
Lovely day today so thought I would take the 67 out for a run. Out in the country about 60 mph, BANG..bang bang.....immediate pull over no doubt something significant wrong.Checked suspension etc nothing wrong there, engine fine, still got all the gears.Noise coming from the rear, wheels/brakes all seem ok.Limped home 15km at 20mph.Seems like my diff is in trouble, and my 67 fastback has castings which indicate original motor, gearbox and diff.I have the 9" 3.25 lsd.
How do I best tackle this while keeping my car as original as possible?
I'm not looking for the cheapest way out , or to "improve" my diff, I want to get it back to where it was in 67.
Pull it out and take it to where ???? for a rebuild?(I'm in WA)
Any help much appreciated.

Don't worry about it ending up not being original. All the parts you would need to repair it are available somewhere.

One thing I will say is that I have never seen a mustang diff in a car that is not raced to death, blow up, and i have been repairing these for over 40 years, so something odd happened to yours.

As far as parts go, i only use us gear or the italian made (not the ones they have made in another country) motive gears and timken bearings.



.

Offline GLENN 70

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Re: blown diff
« Reply #3 on: May 18, 2019, 10:38:50 AM »
That seems very strange . Check the Uni joints 1 st . Jack the car up with a good trolley Jack under the diff center ,then turn each wheel ,look and listen . Uni joint ,broken axle or something in the diff ,hell a 9 inch doesn't break in a stock car . At worst if you know  how too or can work on the car itself ,pull the axles out and check them then the diff center  and look . LSD is rare in mustangs ,most were open .  Rear Uni joint most likely .

Offline shaunp

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Re: blown diff
« Reply #4 on: May 19, 2019, 07:13:34 PM »
Uni joint I reckon

Offline jack67fb

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  • Location: WA
  • Car: 1967 GT S code fastback
Re: blown diff
« Reply #5 on: May 21, 2019, 11:39:47 AM »
Well good news! Turns out i was being a bit dramatic, the problem turned out to be a wheel bearing lots of little pieces of metal....by the time we worked that out we already  had the driveshaft off and the rear uni did have a tight spot, so replacing both uni joints and of course wheel bearings either side, also the diff oil while at it. My diff is an equa lock lsd, very relieved it has survived.

67 gt fastback s code
16 gt fastback

Offline barnett468

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Re: blown diff
« Reply #6 on: May 21, 2019, 01:26:16 PM »
Well good news! Turns out i was being a bit dramatic, the problem turned out to be a wheel bearing lots of little pieces of metal....by the time we worked that out we already  had the driveshaft off and the rear uni did have a tight spot, so replacing both uni joints and of course wheel bearings either side, also the diff oil while at it. My diff is an equa lock lsd, very relieved it has survived.

That makes way more sense, and glad it wasn't the diff. You would nearly have to shoot that thing with a howitzer from point blank range to do any significant damage to it.

 

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