goffemannen

I wounder if the 6speed prop shafts are the same on all new age STI' between 01-07.

I bought a euro 2006 box and diff. I did get a prop but the rear joint is f"cked.

APIDavid

iTrader: (4)

As far as l know all 6 speed prop shafts are the same. Can you not get the one you have rebuilt?

David APi

goffemannen

Ok.

I don't know if it's possible

APIDavid

iTrader: (4)

It is possible here in the UK, so I guess you must have that possibility somewhere over there, it is not a big problem these days.

Good Luck, David

Arch

iTrader: (59)

I dont think they are all the same.

I have a hawkeye STI prop which has a bigger flange size. It needs a 100mm dia diff flange it is just to big to fit onto a 95mm diff flange. The diff disc could be redrilled in the same way as the PCD redrilling works but it is so close to the outside edge I think it would break through, So I think at some stage they changed the size of the flanges on the 6 speed props and diffs.

I have just organised to have one of the UJ's replaced on mine to fit the smaller 95cm diff flange which my diff has. Some of the R180 diff's come with the larger 100mm disc. I was previously running the rear hawkeye R180 diff but sold it when i went to a diff with a Kazz plate unit. It wasnt until I went to fit the prop to the diff that I realised the issue so the hawkeye diffs def have a 100mm dia disc but exactly when this changed is open to debate.

Arch

iTrader: (59)

Drawing below showing dimensions of the hawkeye prop flange and R180 95mm dia disc on the diff.

goffemannen

I have measures my prop and it's like yours on the picture. And my diff is 100mm.

goffemannen

Another thing. I've seen David from API writing that you could use a GC8 AUT prop shaft. That that is actually a better way then a 6speed prop. Is that true?

Mr J

Yes you can, but I'm pretty sure it wouldn't fit a hawkeye diff as it's 100mm

/Jan

goffemannen

Probably not. Well I have to find a new hawkeye prop shaft then.

but should it be possible to change the flangle in the diff?? Maybe to one from a regular R160 diff?

APIDavid

iTrader: (4)

[QUOTE=Arch;10591308]I dont think they are all the same.

I have a hawkeye STI prop which has a bigger flange size. It needs a 100mm dia diff flange it is just to big to fit onto a 95mm diff flange. The diff disc could be redrilled in the same way as the PCD redrilling works but it is so close to the outside edge I think it would break through, So I think at some stage they changed the size of the flanges on the 6 speed props and diffs.

Agreed, But we have never found out why some have a different pitch. It first reared up when l sent a kit to somewhere in Europe many years ago. It is a simple matter of re-drilling the flange to take the different bolt pitch if you get in trouble. Plenty of 'meat ' to be able to do that and all the people that have done it have never mentioned an unsatisfactory outcome.

I have never seen the 'odd' one here, to be able to advise which prop is right or wrong in relation to which model it comes from.

Sometimes you can use the auto prop, but some of the centre bearing supports are off centre which puts an angle in the driveline. Not ideal. The line from gearbox tail to diff flange needs to be as straight as possible.

Good luck, David

goffemannen

[quote=APIDavid;10591528]

Quote:

Originally Posted by Arch

I dont think they are all the same.

I have a hawkeye STI prop which has a bigger flange size. It needs a 100mm dia diff flange it is just to big to fit onto a 95mm diff flange. The diff disc could be redrilled in the same way as the PCD redrilling works but it is so close to the outside edge I think it would break through, So I think at some stage they changed the size of the flanges on the 6 speed props and diffs.

ok. so what do you advise me to do? Get a 6 speed prop or a GC8 aut prop? How can I see on the GC8 aut prop if it's off center?

It seams I can change the flange on the diff to a 95mm. We got plenty of diffs with that flange here at work. So it seems I don't need a 100mm 6speed prop.

APIDavid

iTrader: (4)

[QUOTE=goffemannen;10591547]Good Luck undoing the big nut on the flange, they are seriously tight. It'll be easy enough [ sort of ] to undo the one on the car, as you can lock the brakes and so on.. But undoing one when the diff is laying on the floor is not easy. as you cannot grip them well enough to get a big long "Snap-on breaker bar" on and keep it still.

The only way to see if the auto prop is right or wrong, is to try and fit it, which is too late because by then you have bought it. Try to get one with a refund offered if it doesn't fit or 'borrow' one.

David

goffemannen

I think I can get it off =).


I think I will get the GC8 Aut prop, it is at our other facility so I can get it here for free. And if it doesn't fit I can use the one with the bad rear joint temporary and buy a prop from UK.

Arch

iTrader: (59)

David you are wrong sorry you cannot fit these Hawkeye props to a 95mm diff flange. In your example the diff flanges must have been 100mm or the 6 speed props having the smaller flange size. From the info I have seen it looks like at some point after the WR1 the diffs started coming with a 100mm diff flange but no one has been able to confirm this.

Goffemannen you can use any 6 speed prop on your car. The problem that I had is the opposite to you. I have the smaller 95mm diff flange and the larger hawkeye prop flange you cannot redrill the smaller diff flange to mate the larger prop flange there is just not enough material there.

Your issue is easier to resolve. You have the larger 100mm diff flange so leave the diff alone and do one of the following.

1. Have the UJ's on your own prop replaced. (cost around £100 over here per UJ)

2. Buy another 6 speed prop (cost £100-£150). What you may then have to do is redrill the diff flange to match the prop unless you can source a hawkeye prop which should be the same as you currently have. This is simple to do and is done all the time when the PCD is wrong. The PCD issue often arises when you fit a 6 speed box and prop but have a classic R180 diff. The PCD for the 5 speed props are different. It is simple to do and can be done insitu. I have done it loads of times or it can be done with the diff off the car. Offer the prop up to the diff flange and locat the spigot, spin the diff flange round so that the prop flange holes are approx half way between the old holes in the diff flange. Carefully mark the first hole, centre punch it accurately then pilot drill it. I use a 7.8mm drill and if needs be open it out with a 7.9 then 8mm drill but you want to keep the hole a tight tolerance to the shoulder on the bolts. Once the first one is drilled fit the nut and bolts and then carry on round for the next 3 using the same method.

If you look in the wanted section where i was looking for a 6 speed prop you will see 3 on offer there.

Arch

iTrader: (59)

Also drop stealthy55 a PM he has a low mileage on from an 05 STI available. If you ask him to measure it you may be lucky and find its the same as yours.

goffemannen

I have a flange from a WRX 2000 diff now(R160 i suppose? ) it is 95mm and have the same PCD as the diff in your picture. So any prop except the hawkeye 100mm prop should fit that flange right?

Hmm..go GC8 Aut prop and see if it fits. And if it doesn't fit I can use the one i have with the bad rear joint temporary and buy a prop from UK.

or should i buy a new 6 speed directly? If the GC8 Aut fit it will save me at least £50, depends on how much the seller wants and how much the delivery cost.

Arch

iTrader: (59)

I dont know if an R160 flange will fit an R180 diff never heard of anyone doing it.
Although the pinion shaft position on the diff is set by spacers and shims on the pinion shaft, the torque on the flange nut must have an effect on the position of the pinion shaft in relation to the crown wheel. Unless you are able to accurately retorque the nut I would suggest leaving the diff as it is.

What prop you go for is up to you. David has highlighted a small issue with the autoprop if it was me I would be going for a 6 speed prop.

APIDavid

iTrader: (4)

The pinion pre-load spacer is a fixed length lump of steel. Not a crush tube like some diffs have. so it is not a problem to swap flanges from one to another. Providing the torque is set on the big nut all else falls into place.

David APi

PS it my be that the auto prop from a GC8 won't fit a GD series chassis. And vice versa. I would expect that manual / auto on like for like models to be swappable.

goffemannen

I have already tried to fit a R160 flange. It fits like a charm. No problem changing it. I just used a air wrench to get it loose and to mount it. Can't see why it should be mounted with a specific torque. If it should have a specific torque I think I can get that torque figures. I have a buddy who works on a Subaru workshop.

I got a GC8 Aut prop on it's way here so it should fit fine on my GC8 chassis than David.

The auto prop should be a bit shorter than the manual right? Because the 6 speed box is longer than the 5 speed. Or am I wrong?

APIDavid

iTrader: (4)

6 speed is longer than 5 speed so auto being shorter fits.

David

Arch

iTrader: (59)

David totally agree with the logic ref shims and washers in the diff build up and in theory it should make no difference but a recent thread discussing this very issue gave the torque figure which from memory is 140 lb/ft and also found that one person had an issue with a plated diff after replacing just the diff flange and not applying a torque, I assume using a rattle gun. May just have been unlucky tho.

David only the front section of of the 5 speed prop is a different length.
Again a debate recently said that you can fit the rear half of a 5 speed prop to the front section of a 6 speed prop. I have tried it but both the 2 piece props I have (both from early RA's) have a 57mm spigot at the prop centre split and a 50mm spigot at the diff end where the 6 speed hawkeye prop I have uses a 50mm spigot both ends of the rear prop section. So unless some 5 speed two piece props come with a 50mm spigot both ends then even this may not be possible but in terms of length it would work.

goffemannenare are you interested in selling your 100mm flange.

goffemannen

I would like to keep if for now. I might consider selling it later.

140lb/ft is a lot!! Its 190nm.

stealthy55

will measure it tomorrow

Arch

iTrader: (59)

Looks like I was wrong its actually 134lbft

goffemannen

it's still a hole lot!! =)

Arch

iTrader: (59)

The advice is there for you take or ignore as you choose. The torque setting is 134lbft and the manual also says to lock the pinion shaft and crown wheel in two places before tightening.

NOTE:
• Be careful not to give excessive preload.
• When tightening the drive pinion nut, lock ST1
with ST2 as shown in the figure.
ST1 398507704 BLOCK
ST2 398507702 DUMMY SHAFT
Tightening torque:
181 N·m (18.5 kgf-m, 134 ft-lb)

goffemannen

and that means what? That i should put the driveshafts in before i tighten the nut =)?

sorry for being stupid.

Arch

iTrader: (59)

I am unsure but from the diagrams it looks like a locking tool placed inside the diff somewhere to lock one side and a drive shaft clamped to lock the other and then torque it up. This is why i suggested changing the prop and leaving the diff alone.

You may get away with rattling it tight given that the plunge of the pinion shaft is set by the shims and sized washers but the torque will have a finite effect whether its significant or not would be a question for someone like David who does this day in day out. Personally i would want it torqued correctly.

goffemannen

hmm okey. if ju just need to lock up both sides on the diff its no big deal. Just connect the driveshafts and torque the nut. That is the only way I will be able to torque it anyway, it's when it's on the car