LSD Diff internals



I've got my hands on an LSD from an 85 Fairlane. Does anyone know if you can identify from the outside whether it has a two or four pinion clutch centre. I'm fitting it into my blown (250) XF ute untill I have enough cash for a rebuild and a ratio change. A four pinion should be stronger, but I have no proof of this so I am curious as to why Ford (borgwarner) had two types of LSD's (spin resistance diffs) fitted to their fleet. If it was just a factory modification at what stage were they fitted out. :unsure::
Generally, 4 pinion LSDs were fitted to 5.8 Litre Falcons. I dont think your rear-end will fit your ute anyway without cracking it open, since post March '82 Falcon/Fairlane sedans went to a 4-link rear end setup, while utes and wagons retained the leaf-spring setup (still do).
Thats probabaly a 2 pin high ratio (2.77)? diff, and Im afraid wont be much use to you as its most likely a 25 spline as well. BTW the tag on the diff, can tell you exactly what it is, by contacting BTR.
Try to get one from a ef/l there 28 spline and all 4 pinions, LSDs are a bit harder to find.
The ratios including 2.77 and higher(lower numerically) have their own Differential crown wheel carrier, which cant be used in lower gearsets, like 3 or 3.32, 3.5.
late utes might yeild something more usefull.
Thanx for the help guys. The diff is a leaf spring setup as I have checked it for a fit to my ute. The ratio - 2.77. I've got the part number so will contact BWR for information. I'll probably chase around for either an exchange diff (to a four pinion, 28 spline) or a rebuild to upgrade all internals. The ratio I want is around 3.77.
Cheers Duke
Look no further than a Cortina 4 ( Post 71, TC/TD/TE, but not TF) which was always a 7.625" 3.7:1 diff. Just make sure the pinion is matched to a collapsable spacer, cause Cortina ones were sometimes fitted with a crushabel spacer, and some leaf sprung XD's I've seen have had the earlier shanked pinion. Any machinist can convert the two over, just check the two pinions first!

My mate Danny uses one of these Cortina 3.7:1's in his 72 Charger R/T replica, and it's bullet proof. Richard, the guy with the SC12 blown 3.8 VN Commodore, will be running one in his ride very shortly. And I've got one too, just waitng to go in when my BW auto blows itself to smithereens.

MattXF asked similar questions 'bout this a while back. Click on to this:-

NB// The BW 78 is really a 200 mm crownwheel diff, but some ratios are 7 7/8" (200mm) or 7 5/8". I think the rare 3.27:1 ratio used in some Commodores and Falcons, first saw light of day as a Dana service option for Chrysler dealers who had to replace 3.5:1 E49 diffs under warranty.