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Sierra Diff 7" 3.92 LSD I think


samfransisco

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As per the locost link I posted Rab - see the photos in the thread, they clearly ID it as an LSD

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It is a Ford viscous lsd, I suppose it is possible that if it's had a hard life that it might not be working to normal levels, but they are serviceable at places like Bara Motorsport.

However, do before you go tieing yourself up in knots, make sure that you are testing correctly, if you start testing. Viscous LSD's don't perform like plate/clutch type LSD's and nor do they behave like the torque biasing ATB's.

 

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I think I am already tied in knots. I don't want to misrepresent an item I am selling. I’ll try and contact Bara and see how much a ‘service’ would cost.

Thanks for everyones feedback.

 

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Spoken to BARA motorsport and he was very straight forward that it is an LSD. Service costs about £280 and an updated LSD costs about another £280 more.

 

I can get a proper breakdown of this cost from them in an email. will update when I get that.

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Sorry, had a quick search on the bench test for the viscous diff, but ended up on various Ford/Pistonheads threads and lost the will to live VERY fast. I just had no idea there was such a complete lack of understanding and so, so, much misinformation about them out there!

Bara know what they're doing with these and you're in safe hands with their advice.

But as we've repeatedly said, you can see the viscous module casing in your photo! (Had a look on a proper computer monitor last night), so there's no debate about what it is. It just may be that the silicon fluid in the viscous pack is a bit tired.

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OK. Sent the same info to BARA and got the following response.

 

Hi Mark

 

Yes the diff you have is a Viscous LSD Unit

 

Service & rebuild Axle Inc Dyno Test £200

Service & Reset Vc 120Nm Inc Additional Plates £280

1 x Service Kit All bearings,seals,o rings & C/Spacer £130

 

Total £610+VAT

 

Let me know

 

Regards

 

Bara

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I bought a viscous LSD (mine's a 3.6). When I went to collect it I found that I could twist the flanges in opposite directions by hand, same thing you've found here, but as I'd been planning to get it serviced anyway I went ahead and bought it.

I had mine done by Phil at Road and Race in Sevenoaks, he had it finished the next day, great service. From memory it was about £550 inc VAT for a rebuild with new viscous unit.

And now it passes the twist test!

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IIRC, the standard lsd is only set at around 25 N anyway, which isn't huge, certainly achievable turning a wheel by hand, or on the bench without the need for huge breaker bars.

Can R&R do changes to the viscous pack settings? (Only a few places can).

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Mine had very little resistance just by hand. R&R just replaced it. I think they're sealed units, aren't they?

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They are sealed units, which is why there aren't many transmission specialists able to work on them, Bara is one, well known in our neck of the woods, though there are a small handful of others! :d

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4 hours ago, Chris King - Webmaster and Joint North East AO said:

As per the locost link I posted Rab - see the photos in the thread, they clearly ID it as an LSD

:t-up:

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3 hours ago, Dave Eastwood (Gadgetman) - Club Secretary said:

Sorry, had a quick search on the bench test for the viscous diff, but ended up on various Ford/Pistonheads threads and lost the will to live VERY fast. I just had no idea there was such a complete lack of understanding and so, so, much misinformation about them out there!

Bara know what they're doing with these and you're in safe hands with their advice.

But as we've repeatedly said, you can see the viscous module casing in your photo! (Had a look on a proper computer monitor last night), so there's no debate about what it is. It just may be that the silicon fluid in the viscous pack is a bit tired.

:t-up::t-up:

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Hi ALL

I'm appreciating all the info and comments on here - BIG thanks to y'all! I've got a Westfield Courier Service thread on the go too, to get it up to sunny Scotland:

Mark, you have PM :)

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