AU Diff ratio

WAS 240 · 08-10-2008, 08:07 PM

Gday just wanted to know where to go to see about getting the diff ratio in my au1 xr6 IRS changed to a 3.9, also what is the standard ratio?? its an auto and what sort of cost is it for this and a 3000rpm stallie?? thanks

bodes-sh · 08-10-2008, 10:15 PM

standard should be 3.45. not sure on cost to get it done as it will vary depending on where you go, but i would say easily $1000+ if not more...better off getting people to tell you what shops are decent and call them to get prices. good luck

The Monty · 08-10-2008, 10:24 PM

For the diff gears and LSD its around $2000 for a properly built unit. Stall is around $300, then install and a full flush, plus a transmission cooler ($200).

BLACKAUXR8 · 09-10-2008, 12:56 AM

i don't know were you went monty but i got my 6 cyl Forte's diff done from disc to disc brand new everything including lsd centre for $1050 at Springwood just up from Moss st

mik · 09-10-2008, 01:07 AM

thats a good price i reckon, is that installed and everything?

The Monty · 09-10-2008, 06:53 AM

Is that including diff gears? If so, can you give me the name of the place? (

)?

bloggs24 · 09-10-2008, 02:09 PM

theres a bloke on ebay selling 3.89 diff gears for $250. for the diff gears alone for installation i was quoted about $550, but then i told him it was lsd and he wont do it so when i get the time, im gunna pull it out myself and save a few hundred. theres also a bloke selling 2800rpm torque convertors for $395

The Monty · 09-10-2008, 03:09 PM

You really have to watch out for the ebay ones. They are usually from the old R31 skylies, so would be going on 20 years old, in a most probably thrashed car. Getting them installed also isnt as easy as out with the old, in with the new, you should do all seals and bearings, otherwise they wont last at all. I went through all this a couple of months ago, and to get it done the way it should be done isnt cheap. You can do it the otherway but it wont last.
Three words, choose two : Fast, Reliable, Cheap. You cant have all three.

blackers10 · 09-10-2008, 03:47 PM

also from what i was told the other day.. to set the lap of the gears uses a machine thats about $2000 or more.. so its your money your throwing away if you do it your self

XR6_4EVA · 09-10-2008, 03:57 PM

I was quoted by a melbourne joint 700 bux to completely recondition my LSD then a ratio upgrade to 3.89...

Didnt seem to bad to me. They said they would only do because the place next door had some blue power boys.

WAS 240 · 09-10-2008, 05:12 PM

So whats the verdict on keeping the 3.45 gears and getting the stallie?? 3.45 seems alright would you notice a big difference going to a 3.89 i was looking at the 4.11 but wanted to retain drivability and fuel economy also what sort of cost to get the stallie installed or can i DIY it??

blackers10 · 09-10-2008, 05:18 PM

depends what your after later on. i dont have any issues with 3.45s . some guys have run 3.7s and think they feel quite good
if your planning to turbo the car at all id stick with 3.45s

you can DIY a stall but its much easier to get a shop to fit it
i paid 330 for a gearbox swap.. which would be similar to a stall install as they have to remove the box to fit it.

bloggs24 · 09-10-2008, 07:45 PM

Quote:

Originally Posted by The Monty

You really have to watch out for the ebay ones. They are usually from the old R31 skylies, so would be going on 20 years old, in a most probably thrashed car. Getting them installed also isnt as easy as out with the old, in with the new, you should do all seals and bearings, otherwise they wont last at all. I went through all this a couple of months ago, and to get it done the way it should be done isnt cheap. You can do it the otherway but it wont last.
Three words, choose two : Fast, Reliable, Cheap. You cant have all three.

The quote included seals and bearing etc.

I know im taking a risk by buying the ones of ebay, but i hope it work out :hihi:

Chris :: Why not get both?

WAS 240 · 10-10-2008, 10:15 PM

i deffinatly want the 2500-3000 rpm stallie but im just not sure on the diff ratio upgrade, just because i dont know which ratio to choose for the people that have done it can you tell me about the drivability on the highway with the 3.9 gears?? i think thats what i want the 4.11 is a bit extreme i think

5.0 ED · 11-10-2008, 02:38 AM

a lapping machine for gears is totally unnecessary for installing diff gears, lapping in gears is done in factory before you buy them and if you buy 2nd hand gears they have already done km's and are well and truely lapped in, to add to this it is something that by many diff experts is in fact frownd against as lapping in, is inheriently wearing them out.

When you install used diff gears if you study the gears closely you'll see marks of where the gears run from standard, when you install them in a different diff housing you use bearing blue and copy the location of where the gears have already run. Have done it many times and have never had a noisy one, even after 300,000km's.

Also if you look at the ford workshop manual, it says about installing diff gears, doesn't mention anything to do with a lapping machine and shows diagrams of getting correct alignment with using bearing blue.

Workshops start all sorts of storys to stop people doing things themselve's, why? cause if we do it ourselves they make no money.

blackers10 · 11-10-2008, 10:16 AM

fair enough