Diffs, FAQ

[The Harvester]

Just got hold of a BW80 series 3.46 LSD diff centre which came out of a VX SS series II so it has got the triangle pinion flange and the large rubber donut. Obviously this won't bolt straight up to my round yoke tailshaft in my IRS VS auto.

I want to use the later type triangle flange and rubber donut so I bought a matching VX series II sedan auto-trans tailshaft complete with the triangle yoke and rubber donuts at both ends and also the triangle yoke shaft that slips into the tranny.
I am hoping that the VX tailshaft can be modified to fit my VS or have the ends chopped off the VX shaft and welded to my VS tailshaft.
Does any one know if this would work and does anyone know of a competent business in Melbourne that can do this job for me?

Also will the 2 drive axles in my VS that are on either side of the diff bolt straight up to my new BW80 diff centre?

I have ABS on my VS diff and the VX diff I got also has ABS. My VS diff uses the ribbed cast alloy sensor readers that are straight cut on the diff and the VX diff I got uses the ribbed metal sensor readers that are more rounded like a corrugated roof (If that makes any sense) does anyone know if they are compatible?

 

[Immortality]

you could use the later model driveshaft if it's complete and the yoke fits the transmission output shaft and it's the correct length

for the ABS unit, as long as the number of peaks on the interuptor wheel is the same i don't see a huge problem with compatability. i think you will need to use the VX shafts with the VX diff

 

[Bz Kn33z]

Hey, i have a mate who has a diff he said its out of a holden ute doesnt know what sort, it has leaf springs and the gears are HOLDEN 7421478 3.55 ratio A S
Thats whats printed on the crown wheel. will it fit into my VN BW diff? with a mini spool. thanx really need to know quick

 

[Bz Kn33z]

To my knowing Banjo just springs to mind

 

[padrickz88]

id assume hz or earlier.... because vn+(well vg) had springs in the arse end so a no go to fitting in your housing

 

[Bz Kn33z]

Damnit that really sucks

 

[VR38]

wrong. the crown wheel and pinions are machined as a set and you should never mix em. you can interchange any BW78 gearset, so 3.08, 3.45, 3.73, 3.89,4.11 will all fit using the same center (keeping the crown wheel and pinion together of course)

I was talking crown wheel fitment onto the hemisphere, not mixing gear sets.

 

[Immortality]

I was talking crown wheel fitment onto the hemisphere, not mixing gear sets.

but you were still wrong as you can swap any set of gears into BW78 diff without needing to change the hemisphere. i have 3.45's others have 3.73's, 3.9's fitted without needing to chagne anything other then the gears. i may soon throw some 4.11's into mine for a laugh to see what the car will do with those. i won't have any problem fitting em with my current LSD center or maybe i'll use my open centerwith minispool. don't know yet. one day.........

 

[The Harvester]

you could use the later model driveshaft if it's complete and the yoke fits the transmission output shaft and it's the correct length

for the ABS unit, as long as the number of peaks on the interuptor wheel is the same i don't see a huge problem with compatability. i think you will need to use the VX shafts with the VX diff

I got in contact with Melbourne Drive Shafts & CV's in Campbellfield and they said that to use the later type shaft with the rubber donut you have to be sure that the shaft runs perfectly straight from the diff to the tranny otherwise there would be severe vibrations. They could chop off the rear VX shaft end and weld it to my VS shaft and balance it etc. would be the better option instead of doing both ends. The VS shaft uses a replaceable centre bearing and the VX II onwards shafts use a uni joint and a centre bearing and the bearing can't be replaced. They would'nt fit the diff so they put me onto Preston Auto's and Diffs in Campbellfield.

Preston Auto's said it's best to stay with the round flange and they can swap over the triangle flange and replace it with the round flange so I don't need to modify the tailshaft at all. The pinion needs to be shortened to do this though. The CV's should bolt up to the diff and the ABS is no problem either. I was quoted $350 to replace the flange and modify the pinion and check the backlash on the gears and check the clutches are good then reseal the cover fill with oil and fit the diff centre for me so I thought that was a good deal and so now she's booked in to get done this Tuesday. :yeah:

 

[rubaduckee]

got a small question, i have a vp non irs, 19" rims, and had the single spinner changed and put ans lsd in, problem is the speedo is out (i know is would be) but i was told it had the 3.08 ratio but but now instead of being harder off the line it is much much more doughy, no hard acceleration at all, and the speedo is reading the oposite to what it would be if there were different diff gears in eg 3.45 etc.

i have a feeling they put the wrong gears in, speedo is out by about 10%

thanks for any help