Which LSD Will Fit Auto V6

[sweefu]

Just as the title suggests, i'm looking at buying a second hand LSD for my VY V6 Berlina - Auto. On ebay there are a fair few SS diff's though will these fit? Or what difference is there in fitting a 6 speed ratio ss lsd to an auto v6?

Cheers.

[Sean880]

I would suggest you ONLY buy a diff from a VY - don't just buy any old LSD from a late model commodore.
"
I have an LSD fitted to my VY supercharged V6 auto as I ordered the car with this option.

1. Make sure when you inspect the diff it has a metal tag attached to the rear FILLER PLUG with the words imprinted on it as follows:
"LSD USE APPROVED LUBRICANT + FRICTION MODIFIER"

If the diff does not have the metal tag attached then do not buy it even if the seller swears it is an LSD.

2. The LSDs and standard diffs set up for the VYs have an identifying code.
There must be a white sticker on the driver's side of the diff housing. This contains various codes, the diff serial number and the diff ratio. The sticker does NOT say if it is LSD though. Only the metal tag has this info. Do NOT buy a diff if the white sticker has been removed or if it is damaged and unable to be read.

The diffs fitted to the VYs have code "FH" imprinted in large letters on the white label together with an 8 digit number. This sits above the Serial Number.

Below the serial number on the white label is the diff ratio. The autos with LSDs all had a diff ratio of 3.08 or 3.07. (Mine is 3.07). So did the auto/manual V6 and the auto V8 cars with the standard non-LSD diff so you cannot identify whether a diff out of an auto is LSD solely from the diff ratio.

(The 6 speed manual V8 VY cars came with a much lower diff ratio at 3.46. Fit this on an auto and you will be running the engine too fast in all gears at normal road speeds and your economy will really suffer).

I would be very wary about buying a used LSD off ebay or from a similar source. There are many damaged and clunky noisy diffs that have been removed from thrashed commodores and sold off to unsuspecting amateurs on places like ebay. Unless you are a diff expert you will not be able to identify a good one from a dodgy one when it is off the car. Diffs are expensive to repair so if you buy a bad one you will be throwing away lots of good money.

I would contact a reputable diff specialist in Sydney and discuss your plan with them. These people are much more likely than you to locate a good serviceable diff for your car, fit it up for you properly and guarantee their work.

A diff is a critical and major section of the driveline and if you cannot afford the cash to have it done by a professional I would leave it alone.

[nick_]

You gotta be stupid to not want to upgrade the diff ratio from the standard 3.08 unless you do heaps of highway/freeway kms.. Upgrading the diff ratio to 3.46 or even 3.73 will give you the most bang for buck on a mild v6.. A 3.46:1 lsd from a manual v8 is the best all round compromise but you will need to have the 'speedo settings' changed with tech2..

[Sean880]

3.46 final drive ratiois not a good compromise for the auto which is why GM did not use or offer this lower diff ratio in the automatic cars or the 5 sp manuals.

The 6 speed manuals used in the v8s have completely different gear box ratios to those boxes used in other vehicles so the 3.46 diff is specifically matched to that 6 speed gearbox.

All you will largely achieve with a 3.46 final drive in a V6 auto is your engine running faster at all road speeds in all gears and an increase in fuel consumption and hence fuel cost. (And you will have to pay for the speedo to be recalibrated to keep the vehicle legal). If people think that result is an improvement for a minor increase in acceleration then good luck.

If you want more performance buy a V8 and be done with it. It's a cheaper and easier way to go in the long run. You get the LSD as standard whichever gearbox you choose.

Used VY commodore sedans are not worth that much now unless you have an exceptional low mileage higher spec car that's been unmolested. So they are not worth throwing a lot of money at in terms of mods.

[soop]

Mate, if everyone had that opinion no one would spend a dime on cars.

Most people arent fussed about economy when they're talking about "performance mods" everything has a downside.

[TMM]

3.46 is pretty mild. I really doubt that a 12% increase in engine speed (3.46 vs 3.08) is going to cause a lot of difference in fuel economy. The largest factor will be the drivers increased tendency to lead foot it everywhere with the high ratio LSD

At 100kmh instead of cruising at 1800rpm you're cruising at 2000rpm. Not a terribly large difference imho. In fact a V6/4L60E in 3rd gear @ 100kmh (2600rpm~) isn't even that bad.

[one_and_only2004]

3.46 final drive ratiois not a good compromise for the auto which is why GM did not use or offer this lower diff ratio in the automatic cars or the 5 sp manuals.

The 6 speed manuals used in the v8s have completely different gear box ratios to those boxes used in other vehicles so the 3.46 diff is specifically matched to that 6 speed gearbox.

If you want more performance buy a V8 and be done with it. It's a cheaper and easier way to go in the long run. You get the LSD as standard whichever gearbox you choose.

Used VY commodore sedans are not worth that much now unless you have an exceptional low mileage higher spec car that's been unmolested. So they are not worth throwing a lot of money at in terms of mods.

Strange, My V6 5 speed came with the 3.46 LSD fitted factory - sits at about 2400rpm on the highway before i swapped the M35 out and put a T5 in. I know at least 3 other people who own VU-VY V6's running a 3.46 ratio factory - so stop pretending you know everything.

You seem to be quite a boring person - no offense intended there, but the fair majority of people on here are all about making their cars poke around a bit harder than what they do from factory - if we worried about fuel costs and resale value I don't think any of us would have bought a commodore.
Speedo recalibration costs a whopping $50 so it's hardly an expensive affair.

[VTPREDATOR]

wouldnt 3:46 actually improve around town economy????

[soop]

Nope, the engine does more revs to do the same RPM.

[Adam_88]

I've just got a try-trac with 3.9.1 gears and it didn't change it to drematicly it's definately more fun driving around town. I wouldn't get one off eBay because you won't know how worn it is. If you don't want change the ratio I found it cheaper to get the hemisphere changed to an LSD one, tru-trac's ($800) are a pretty good bang for your buck but if you want to go better there are kaaz ($1300just for the hemisphere) beacause the stock LSD's aren't that great

[sweefu]

Thanks for the help with this. Do you think buying an LSD from an SS second hand with <100 000km on it would be okay? Or alternativly buying a reco'd SS lsd?

If i did get an LSD out of an auto ss would it bolt straight in?

Cheers.

[Adam_88]

Yep it would bolt straight up but if you went with the second hand one I'd get it tightend first