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**nib** · 28 February 2016, 18:25

I had that happen to me on a stag I owned in the 80s, the noise it made when it snapped I thought what the heck is that,same as yourself one of the gears had broke in the diff causing it to lock up.

**thebadleys** · 28 February 2016, 18:31

Originally posted by thebadleys View Post

Decided to give the car a good road test yesterday after the suspension rebuild, so, off to the daughters just past Leeds, 42 miles on the M62. Ran very well at speeds up to 80 mph (when overtaking).

Set off back and still going well, frightening a couple of people with its acceleration when overtaking, dropping down towards Manchester from the highest point cruising at 75 mph, lifted the throttle and immediately a loud rotating noise, WTF!!!! Pull over to the hard shoulder noise still going, sounds like I've got something round the prop, switch off, check under the bonnet looks OK, start up,noise returns, look underneath at rear and I can see the diff flange resting on the silencers lazily spinning (it's an auto).

Well that's not good, so call Carole Nash Breakdown and within 45 mins recovery truck comes to recover me and take us home. Stripped down this morning and this is what I found.

[ATTACH=CONFIG]36659[/ATTACH]

Quill shaft sheared, ( you can see on the dirt shield where it was bouncing on the exhaust) this doesn't look good, so drop the diff with suspension, remove the rear cover and look at the damage.
[ATTACH=CONFIG]36660[/ATTACH][ATTACH=CONFIG]36661[/ATTACH][ATTACH=CONFIG]36662[/ATTACH][ATTACH=CONFIG]36663[/ATTACH]

Not good, quill shaft obviously sheared when I think the planet gear shaft must have locked the diff and gears burst, not a good sight.

Anyone got a 3:45 diff ??

Further examination it looks like the roll pin that hold the planet gear shaft must have initially failed to allow the shaft to move

**milothedog** · 28 February 2016, 19:19

Nigel, whilst its bad news that your diff decided to commit suicide you should look at it another way. Imagine what could have happened at 70+ MPH if the the rear wheels had locked up or the prop had let go completely and come in to contact with the road surface.

Maybe buy a lottery ticket this week

Ian.

**thebadleys** · 28 February 2016, 19:26

Originally posted by milothedog View Post

Nigel, whilst its bad news that your diff decided to commit suicide you should look at it another way. Imagine what could have happened at 70+ MPH if the the rear wheels had locked up or the prop had let go completely and come in to contact with the road surface.

Maybe buy a lottery ticket this week

Ian.

Thanks Ian,

You are right, the consequences could have been disastrous, I think that because I was going down quite steep section of the motorway and I had a head of steam up lifting the throttle pedal probably save considerable damage, also being a auto I think may have reduced the torque.

Oh, I did buy 2 Lottery tickets whilst waiting for the recovery and guess what ? I didn't win !!!!

Nigel

**wilf** · 28 February 2016, 19:42

+1 on Ian's comments, a very lucky escape.

Last time I saw anything like that, the sheared propshaft dug in and catapulted the car into the air.

**nib** · 28 February 2016, 20:42

Originally posted by milothedog View Post

Nigel, whilst its bad news that your diff decided to commit suicide you should look at it another way. Imagine what could have happened at 70+ MPH if the the rear wheels had locked up or the prop had let go completely and come in to contact with the road surface.

Maybe buy a lottery ticket this week

Ian.

I think Ian the quill shaft will go first especially going at some speed before it locks the car up, my prop from what I can remember was bouncing about on the exhaust which could be dangerous cutting into the fuel line and sparks.
Mark

**thebadleys** · 28 February 2016, 20:47

Originally posted by wilf View Post

+1 on Ian's comments, a very lucky escape.

Last time I saw anything like that, the sheared propshaft dug in and catapulted the car into the air.

One of the benefits of the Stag in this situation is the double silencer which need to be removed to gain access to the prop shaft, they are what save my newly reconditioned shaft from hitting the road with whatever consequences.

Being a BW35 with a sliding front joint it may have been possible for the shaft to slide out of the transmission with the consequential loss of transmission fluid.

Hells Bells, the more I think about it I realise how VERY lucky I was.

Nigel

**E-LAD** · 28 February 2016, 21:38

Hi Nigel,
wow that was scary! You were lucky whilst being unlucky! Hope you can get sorted soon.

Dale

**flying farmer** · 28 February 2016, 21:50

I have had a couple of diff explosions in my 3.9litre RV8 engine Toledo when the small gears have shattered (Sprint Diff and TR7 diff, but the small gears are the same)
On the first occasion the diff locked solid while giving it some welly out of a junction. The propshaft twisted through 180 degrees before shattering the rear joint and attempted to gnaw its way through the floor, the three back seat passengers all had their feet up on the seats!
On the second occasion the diff locked while accelerating out of a corner which caused a rather interesting opposite lock moment, then the shattered gear was ejected through the diff casing freeing the diff. Fortunately I was only a mile from home this time and was able to drive the car home leaving a trail of EP90 behind me!

Both these instances it was the actual gear which shattered, but as you say it rather looks like the pin has come out this time.

Neil

**thebadleys** · 28 February 2016, 21:51

Originally posted by E-LAD View Post

Hi Nigel,
wow that was scary! You were lucky whilst being unlucky! Hope you can get sorted soon.

Dale

Thanks Dale, as I said before the more I think about it !!!

**Rubce** · 28 February 2016, 23:57

Hi Nigel

"YIKES"

Glad your okay though. Good luck sourcing a replacement diff.

Regards

Bruce

**hmarsh** · 29 February 2016, 00:21

Hi Bruce, I have the Stag in Brereton Green, and my quill shaft tube snapped in Derbyshire last summer. Got new diff. and new quill shaft assembly, and had gussets welded to the tube to give extra strength and stop it breaking again. I suspected a problem it the diff. as it had far to much free movement when the prop. shaft was turned to take up the backlash. Car is much better now the all the play in the transmission removed. The main thing is that you were OK ! It happened to a friend of mine and he did three spins before he came to rest; and missed everything !

**thebadleys** · 1 March 2016, 20:35

Decided to put the original 3.7 diff back until I can find a 3.45, so started a bit of a recon, new seals, output shaft bearings and set planet wheels to zero backlash along with new quill shaft bearing.Difficult to find a method of holding the diff to work on so thought about ia and came up with this

IMG_2307.jpg
IMG_2308.jpg

(can't get photos correct, but the diff doesn't fall off !!)

Upside down axle stand clamped in my vice, works a treat Nigel

Attached Files

IMG_2307.jpg (77.2 KB, 52 views)

**StagJonno** · 1 March 2016, 22:17

Originally posted by thebadleys View Post

Decided to put the original 3.7 diff back until I can find a 3.45, so started a bit of a recon, new seals, output shaft bearings and set planet wheels to zero backlash along with new quill shaft bearing.Difficult to find a method of holding the diff to work on so thought about ia and came up with this

[ATTACH=CONFIG]36676[/ATTACH]
[ATTACH=CONFIG]36677[/ATTACH]

(can't get photos correct, but the diff doesn't fall off !!)

Upside down axle stand clamped in my vice, works a treat Nigel

Surprised it's not rolling off - is bluetack your secret ingredient?

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