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Another diff question. Sorry!
owelly - 25/6/12 at 05:45 PM

I know you'll all tell me to do a search but I'm chasing myself round the bend! I've read through dozens of threads and been here sierra data but there's nothoing that quite matches what I'm looking at!
I bought a XR4x4 diff a few years ago and have just built a de-dion to use it. When I bought it, I checked the little tab on the diff and although I can't remember the letters and numbers, it had AA on it and according to the info I could find at the time, it was an LSD.
I accidentally poked a hole in the diff back cover the other week so I've taken it off to weld up. And to my horror, there's an open diff looking back at me! I thought it seemed veru much like the open Atlas I'd just taken out!
Anyhoo, the figures on the crown wheel are as follows:
362 83BG 4210 SD
I thought it was 362 83B6 4210 SD but its hard to read.
Written in painty-pen on the crown wheel is: 1256 362
Thanks in advance chaps/chappesses.

[Edited on 25/6/12 by owelly]

jacko - 25/6/12 at 05:58 PM

I have a lsd diff and it looks just like you say and from what i remember the nombers etc ar the same as yours
362-83bg
mine came out a 4x4 too
there is some info in my photo archives if you have a look
have you looked at the link below
Graham
http://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=85080

[Edited on 25/6/12 by jacko]

phelpsa - 25/6/12 at 06:00 PM

It is a normal open differential with a viscous pack on the other side of the crownwheel. There's nothing fancy about the differential part of it.

mark chandler - 25/6/12 at 06:13 PM

It does fool you, the bit that mounts the crown wheel is a bit fatter as the LSD half is contained within this, it works by binding the halfshaft to the crownwheel on one side thereby locking the centre planet gears, simple but effective

owelly - 25/6/12 at 06:14 PM

Cheers guys.
Jacko, I had a looksy at your archive stuff but could'nt find a match.
Phelpsa, what the heck is a viscous doofer doing on the crown wheel? Whats the idea of that?
And another thing: as I understand it, the 7" diff has one long bolt through the top mounting, like mine has, yet there seems to be 7 1/2" diffs for sale that have the same bolt arrangement as mine. According to the 7th heaven data stuff, the 7 1/2" should have two bolts for the top mount. I'm confused.com. Whats right?

jacko - 25/6/12 at 06:21 PM

http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=7vs7.5diffs2.jpg
Jacko

owelly - 25/6/12 at 06:28 PM

Goodo. Mine is a 7" (fnarf fnarf) and those advertised as 7 1/2" are wrong. So as long as I get one with the single bolt top mount and lobro shafts, and an LSD, I should be OK?

owelly - 25/6/12 at 06:30 PM

Here's what I'm looking at..


jacko - 25/6/12 at 06:34 PM

http://www.locostbuilders.co.uk/viewthread.php?tid=126868
this looks like mine

owelly - 25/6/12 at 06:38 PM

quote:

The sierra LSD is a viscious coupling type so it looks like an open diff but the back of the crown wheel and the carrier are thicker than on an open diff to accomodate the viscious bit.


Muh? So Sierras didn't have a proper LSD? They just have a viscous pack on the crown wheel? Blimey, every day's a school day!

snapper - 25/6/12 at 06:52 PM

One on the left is an LSD

owelly - 25/6/12 at 06:59 PM

My brain hurts.......
So I DO have what FoMoCo call a LSD. Goodo, but it doesn't actually work like a LSD.....

jacko - 25/6/12 at 07:34 PM

To baffle you more look at Google images put in
sierra lsd diff

mark chandler - 25/6/12 at 09:38 PM

quote:
Originally posted by owelly
My brain hurts.......
So I DO have what FoMoCo call a LSD. Goodo, but it doesn't actually work like a LSD.....


Yes it does

Normal diff the half shafts locate in the planet gears, so to lock up you can weld the planet gears up so now the halfshafts are effectively tied to the crown wheel.

All this is doing is locking 1 x halfshaft to the crown wheel, effectively the same thing.

owelly - 25/6/12 at 10:10 PM

But Shirley, that means that only one drive shaft has the limited slip and the other doesn't?

Chippy - 25/6/12 at 10:35 PM

The diff that you have will work just like any other LSD, its just that Ford took a differing aproach to getting the same result. I had one fitted to my V6 and it worked just fine, I now have a Quaffe one due to changing to a 3.14 diff with push in shafts, and that doesn't seem to work as well. Cheers Ray

gunman - 25/6/12 at 10:49 PM

I had the same moment of horror when I took the cover off my xr4x4 diff. It is an LSD from your pics. I have mine fitted now and it works great.

mcerd1 - 26/6/12 at 07:44 AM

quote:
Originally posted by owelly
But Shirley, that means that only one drive shaft has the limited slip and the other doesn't?

no, the other shaft is effectively locked too…

forget the crown wheel for a moment, now you've just got the 4 small gears in a square which can all spin freely together - so if you then lock one to the housing none of the rest can turn

takes a minute to get your head round it but trust me it works - I conducted several hours of 'testing' a sierra donor with a ford LSD just to make sure


I had the same moment of panic when I opened mine, but I also had an open diff at the same time - the only visible differnces I could find were the lump in the middle of the crown wheel (as per snappers's pic) and the axle stubs are unequal lengths on the LSD

if your still not sure, hold the propshaft still and try turning the driveshafts in opposite directions - if its a working LSD it will be hard work....




[Edited on 26/6/2012 by mcerd1]

owelly - 26/6/12 at 08:59 AM

PING! Got it! I've got my fuzzy little head round it now.