T5OLF

iTrader: (4)

So you don't need to use an LSD type oil in a dccd box? some of the stuff I've read says you do.

johnfelstead

No, you use a non LSD oil in the box. If you read the service manual for the STi5 RA it tells you in there, the only difference between the classic DCCD box and normal box regarding oil is the service interval goes from 40,000km to 20,000km. The factory spec is a 75W-90 GL-5 oil in the box, a 75W-90 GL-5 LSD oil in the rear diff, rear diff has a 40,000km service interval.

The new age car has the same oil requirements in the 6 speed DCCD box and plated rear diff. The only info i have service wise on that is the USDM model, which doesn't have a shorter service interval for the trans or diff oils to VC equipped models.

danny-goddard

ok so if my dccd should be running free @ 65/35 how come when i drive round and round the inside wheel is skipping?? like the dccd is engaged

T5OLF

iTrader: (4)

I would buy a controller other wise no real point in having it, you may as fit a normal centre diff to the box.

These are worth a look at, I bought the dual auto one but you can get a manual for little money.

DCCDPro.com

danny-goddard

nice one yeah the hole point of fitting the dccd was to have it all working i just havnt got round to it yet i only fitted the box on sat are the controllers easy to conect?

T5OLF

iTrader: (4)

Those are very easy to fit, just a few wires. Pos, neg, throttle pot and two wires to the box, job done.

I would spent a little more and get the dual one rather than the manual one.

Another thread, spiider is the guy who makes them.

http://forums.nasioc.com/forums/show....php?t=1366253

http://search.asterpix.com/cy/242254...ioc.com&t=site

Fat Boy

Danny

Glad John has updated re the oil as he does know his stuff.

Is the diff definitely not wired up? Just wondering if there's a the possibility that its wired up the wrong way around and locked instead? Although that would make horrible clonking noises and grabbing effects when manouevring at slow speeds

danny-goddard

No mate the only thing that is wired up on the box is the reverse light and one other plug that I'm not sure about. the two wires that come from the dccd are just left disconnected

johnfelstead

Inside rear? if so rear diff preload may be set high.

johnfelstead

Your first statement is not true, the DCCD centre diff setup is well worth having even without a controller, most of the time you drive with the diff open anyway in a none active DCCD car.

The statement in the link that "Running without a controller risks breaking expensive drivetrain components" is also a nonsense.

danny-goddard

yeah it is the inside rear how do i sort this i hope your right many thanks

johnfelstead

Try a different oil first, some oils give the effect of having a tighter LSD.

If that doesn't work then you will be looking at removing the diff and checking the plate stack in the LSD, it may be setup with more friction faces in contact than normal, or it's using a lot of preload. You can buy a diff service kit with different thickness plates to enable you to soften the preload off if you find it's too tight for you to get on with.

danny-goddard

ok thank you what oil would you recommend to try is it the 75/90 lsd oil?

danny-goddard

how much of a job is it to do the work on the diff i take it you mean the rear diff? ive done all the work myself ie-new clutch, fitted new box, rear diff and shafts. by running it the way it is now would you say its dangerous??

T5OLF

iTrader: (4)

Cool, just thought fitting a dccd and not using it seemed pointless. So would you say running it using the manual controller has no advanages over running it open with no controller?

Are there any advantages using the auto controller or should he just leave it open with no contoller at all?

johnfelstead

If you are a competant mechanic you can do it yourself, but it involves removing the Crown Wheel from the diff, stripping the internals of the diff, checking the plate stacks and changing them, then rebuilding it all.

Without seeing the car i cant comment on how bad it is or if it's even a problem at all. With a tight rear diff you tend to have some low speed understeer built into the car, but it can help with traction and can be a nice setup for high speed.

In winter you do notice the rear diff tightening up as the oil viscosity is efectively thicker which has the effect of increasing the diff preload. I can certainly feel the rear diff binding slightly at low speed when exiting a T junction, thats normal.

Any decent quality oil to the right spec should do, i only use the motorsport spec stuff because i might do the odd sprint or trackday, so it gives more protection at high load, it's not needed for normal road use.

johnfelstead

But you are using it, you've just changed the diff from a 50/50 split with a Viscous coupling to a 66/33 split diff with no Viscous coupling, which alters the cars balance significantly.

I didnt say running the controller gave no advantage, i said you can use the car without one. If you want to pick up traction in the wet or want to alter the balance you use the controller to alter the centre diff preload to do that.

I wouldnt bother with a pre MY05 Auto controller setup, it's not very good and builds in a lot of understeer, the MY05 Auto setup is very good and worth fitting, but that needs a lot of work as you have steering position, G and Yaw sensors to install and you have to interface it to the engine ECU for throttle input and also the ABS for brake and wheel speed inputs. You might be better off fitting an aftermarket controller if you want to go Auto, but i've no experience of the budget Auto controller linked earlier so no idea if it's any good and has enough inputs to do the job well. A manual controller is normally good enough for most peoples needs.

I've found with DCCD equipped cars, tyres makes a huge difference to how the cars drive. Low grip tyres dont work that well for most people because they are too ham fisted with the throttle and then wonder why the've just spun when exiting a slow corner, especially in the wet. Buy good quality grippy tyres and you can get away with being an animal most of the time. For example I found the OEM fit Pirellis on the P1 apauling when fitted to an RA, way too hard a tyre for the wet with the more rear biased torque split.

Fat Boy

The pirellis were appaling on the P1 as well - in the wet, but they weren't bad in hot and dry conditions, due to being hard as you say. Having said that they were a hoot on track in the wet if you just wanted to hoon about sideways.

thoughto

iTrader: (1)

Sorry to butt in, I have a version 4 STI (non-RA, no DCCD), and want to change my diff oil. Would I want 75W-90 regular gear oil or some sort of LSD specific type? My tranny serial is TY752VBCAA, last owner thought it might have been some kind of "special diff", but looks like the one on my 2002 US WRX.
It has been suggested I keep away from synthetics with moly additives as they might be too slick. Thanks for any advice.