diff identity help

[Rusty]

Need help identifying diff and diff centre.

Numbers read 0575-026 GH 3.91 BTREng2 7f25

Appears to be a 10 bolt Borg Warner with vl 3.91s and some form of locker? I'll add a pic soon

 

[Rusty]

Bump please

 

[Rusty]

 

[WazzaVN]

It is an lsd from what i can tell, so it won't be a locker. Check the crown wheel to see if it has the ratio written on it. it's hard to tell what ratio it is from pics lol.

 

[Rusty]

Thanks mate. Numbers in first post were from the crown wheel so I think the 3.91 part is ratio? It definitely doesn't feel like a standard vs ute diff.

Engine an box etc is worked. Previous owner recalls spending heaps on the diff but had too many head knocks to recall details.

I really appreciate the help

 

[Rusty]

 

[WazzaVN]

I throw this pic around a bit but I'll put it here too for future reference

You can tell an lsd from an open centre from where the split is.

so yeah you got yourself a 3.9 lsd man. Not bad!

 

[shadetreemechanic]

Pretty sure that is a BW75 LSD (same as commodores) from a series 3 R31 Skyline auto that has 3.91 gear ratio, the older series had a 3.89 that had some problems so they changed it.

 

[Rusty]

Interesting. Thanks mate. It was built late 90s if that helps. The diff and ute has done little to no work though.

So it would appear that it's definitely an lsd just a matter of which one. I am pretty sure I came across them in vl turbos or some fords or something similar.

I'll do some research on the r31 diff when I get some time

Thanks again guys

 

[shadetreemechanic]

I think all the borg warner LSDs are the same - cone style setup.
The only difference across all that used the series 75 diff (LSD and non LSD) is the gear ratio...commodores, falcons, skylines and pintaras all used the same diff.

This is a ref i found online from a guy who worked at Dana/borg warner

MODEL 75
HOLDEN VK - VT - all models
VT - VZ - V6 only
NISSAN R31 Pintara & skyline
FORD All Cortina 6cyl
All Falcon up to early AU


MODEL 78
HOLDEN VT- VZ ute with beam axle
VT - VX V8
FORD Late AU - BF 6cyl - with bigger pinion bore.


MODEL 80
VX - VZ all V8 with IRS. Inc ute.

MODEL 86
HOLDEN All Crewman & 1 tonner with V8
FORD BA - BF XR6T & XR8


Easy way to check which model you have ..the pinion stem will have a serial number on it...starting with 0575 depicts its a model 75 & 0578 a model 78. They actually stand for the dia of the crownwheel..... 75 being 7.5" dia.... & 78 being 7.75" (7.8" close enough) dia.