Rear Diff. Information

[DevilYellow]

Well I think I found different rear gear ratio's. Unfortunatly, the retail on the unit is around $1,100. Apparantly they also changed castings right after the first month or so of production. The early ones are heavier but stronger, the lighter ones are having problems holding up and they are trying to go back to the heavier castings. I am trying to get more info and will post as I get it. Knowing the dealer pricing they will problably sell around $900.

[BillyGoatGruff]

Do we know if the rear end is a 8" or and 8.5" ?
Do we know where the casting number is on the rear diff?

[gtofan]

Well I think I found different rear gear ratio's. Unfortunatly, the retail on the unit is around $1,100. Apparantly they also changed castings right after the first month or so of production. The early ones are heavier but stronger, the lighter ones are having problems holding up and they are trying to go back to the heavier castings. I am trying to get more info and will post as I get it. Knowing the dealer pricing they will problably sell around $900.
Please pardon my negative response to that revelation, but this kind of news is starting to get old. So now the much-vaunted Dana rear ends are "having problems holding up"? That's a pretty significant problem, at least in my opinion. Particularly unwelcome news for those with cars having the later lighter weight versions. As if there weren't enough problems with the electrical system/electronics on these cars. Think Pontiac might be planning a recall (fat chance), or will they "fix" them as they fail? Wonder what the next big surprise is? :(

[Adam4356]

Interesting news. I'm gonna hold off judgement until we see what really happens in the hands of owners and more importantly what happens at the track.
Just based on fbody discussion i wasn't planning on expecting to run slicks and not destroy the dana. I just hope the rear is enough to handle some DRs and some hard ass launches.
Price to fix the rear or change gears will probably be alot. Vette mods to the rear are expensive and i don't see the GTO being different.

we'll see

[DevilYellow]

Well, this is all just what is coming back when doing research on the ring and pinons...

I will find out definatly how the different castings effect us. I posted this to see if anyone else has heard anything similar.

[Lumina ss]

Diff is a Borg Warner Hydra track viscous LSD 3.9 gears are about US$670 fitted in Australia. Youve pretty much gotta change the whole damn centre a dozen good burnouts and it will turn into a single wheeler. ford 9" assemblys that bolt to the existing half shafts are available over here for about US$2000

[speed_demon_freak]

Well I think I found different rear gear ratio's. Unfortunatly, the retail on the unit is around $1,100. Apparantly they also changed castings right after the first month or so of production. The early ones are heavier but stronger, the lighter ones are having problems holding up and they are trying to go back to the heavier castings. I am trying to get more info and will post as I get it. Knowing the dealer pricing they will problably sell around $900.


When did the production start?

my build date was 9/03. Does that mean I have the stronger one?

[DevilYellow]

yes, production really started in september. my car was 10/03

[Lumina ss]

some ones spinning stories The diffs have been interchangeable since nov 2000. From nov 99 to nov 2000 a different center was fitted 1 year they are not interchangable ratios avaialable are 3.45, 3.07, 3.73, and 3.91.

VT is 1999 VX is 2000 to present quoted in $AU exchange rate .78 to $US

KAAZ Limited Slip Diff Centre Assembly, VT-VY Commodore $ 1,995.00
9" Diff VT/VX LSD (28 - 31) optional Spline $ 10,995.00
VT 3.91 Differential Gear Set $ 829.00
VT 3.73 Differential Gear Set $ 827.00
VT 3.46 Differential Gear Set $ 569.00
VT 3.46 Differential Gear Set (suit 19mm pinion nut) $ 689.00
VX 3.91 Differential Gear Set $ 969.00
VX 3.71 Differential Gear Set $ 827.00
VX 3.46 Differential Gear Set $ 786.00

[tterbo]

Diff is a Borg Warner Hydra track viscous LSD 3.9 gears are about US$670 fitted in Australia. Youve pretty much gotta change the whole damn centre a dozen good burnouts and it will turn into a single wheeler. ford 9" assemblys that bolt to the existing half shafts are available over here for about US$2000

Do you know who makes the 9" conversion? I emailed Harrop about 2 weeks ago but did not get a reply.

[Lumina ss]

capa performance sell them

[rushhour]

Devil - any way to tell which casting is which?

[COSMO GUY]

These #'s and rear ends sound like my '87 IROC. Borg Warner 9" bolt rear end from Auzzie Land. Posi-rear and rear vented disc ??? G-92 performance set up.

[BillyGoatGruff]

The rear end is a 8.5" rear. This has been confirmed via GM and a supplier from down under.

[gangster1]

Question for the gearheads. It seems to me that changing to say a 3.73 gear would lower your 1/4 e.t. and 60' times. My question is, what would be the drawbacks to doing this (if any)?