Toyspeed.org.nz Message Board

by **cat007** » Sun Sep 12, 2010 11:15 pm

Ok so I was a little bored last night, launched at the lights in the wet in a GTT ST215. It felt like I might as well have been in a FWD.

And then there was a burnt oil smell - not clutch, but smelt a like gearbox oil, but I could be wrong.

What's the center diff in these things like?

by **cat007** » Wed Oct 06, 2010 5:41 pm

No-one has ever had this?

I've noticed that if I go WOT in first gear, when the boost kicks in (other than my head hitting the head-rest) I sometimes get a tiny squeak from the front wheels.

What's the front to back ratio on these things supposed to be? How do you adjust them? I'm guessing it's a matter of pulling the engine/gearbox/diff out and checking the center diff?

Maybe some new fluid might help? We put fresh stuff in when we did the clutch, that was December/Jan 2008.

Santa's TardMe Listings · by **Santa'sBoostinSleigh** » Fri Oct 08, 2010 1:54 pm

im sure the back wants to go around before the front on mine

by **sergei** » Fri Oct 08, 2010 2:03 pm

The centre is a viscous.
You cannot adjust it anyway.
It is 50:50.

by **cat007** » Fri Oct 08, 2010 2:05 pm

sergei wrote:The centre is a viscous.
You cannot adjust it anyway.
It is 50:50.

Hmmm so perhaps I should be using a more specific type of fluid? As I said, the fluid's not old but it was pretty generic.

Any suggestions on what fluid I should be using?

Thanks again

by **iOnic** » Fri Oct 08, 2010 2:09 pm

Pretty sure they're a sealed unit with silicone oil and not really serviceable?

by **cat007** » Fri Oct 08, 2010 2:21 pm

iOnic wrote:Pretty sure they're a sealed unit with silicone oil and not really serviceable?

ohhhh - so they don't use the diff/gearbox oil? The have their own setup?

by **iOnic** » Fri Oct 08, 2010 2:33 pm

I can't confirm it for a Caldina as I'm not 100% certain but I know the ST205/185/SW20 viscous couplings are sealed units and have separate oil to the gearbox. They can't be (easily) drained/refilled with new oil after the original oil has degraded.
This is the 205's viscous coupling

by **strx7** » Fri Oct 08, 2010 5:29 pm

the naming on those parts isn't actually correct, what is labeled as the 'centre diff' is actually the front diff as the side gears etc inside that diff are the ones which drive and allow slip to both front axles.
what is listed is the 'transfer' is technically part of the centre differential which also houses the viscous coupling. the small shaft at the RH end of the viscous coupling goes right thru the centre of the VC and gives drive to the RF axle.

by **cat007** » Fri Oct 08, 2010 5:52 pm

strx7 wrote:the naming on those parts isn't actually correct, what is labeled as the 'centre diff' is actually the front diff as the side gears etc inside that diff are the ones which drive and allow slip to both front axles.
what is listed is the 'transfer' is technically part of the centre differential which also houses the viscous coupling. the small shaft at the RH end of the viscous coupling goes right thru the centre of the VC and gives drive to the RF axle.

So the part that actually controls the 50:50 split between front and back....how can you make that work betterer?

by **sergei** » Fri Oct 08, 2010 6:30 pm

cat007 wrote:
strx7 wrote:the naming on those parts isn't actually correct, what is labeled as the 'centre diff' is actually the front diff as the side gears etc inside that diff are the ones which drive and allow slip to both front axles.
what is listed is the 'transfer' is technically part of the centre differential which also houses the viscous coupling. the small shaft at the RH end of the viscous coupling goes right thru the centre of the VC and gives drive to the RF axle.

So the part that actually controls the 50:50 split between front and back....how can you make that work betterer?

you cannot it is that sealed unit that labelled as VC on the pic.

by **iOnic** » Fri Oct 08, 2010 6:56 pm

strx7 wrote:the naming on those parts isn't actually correct, what is labeled as the 'centre diff' is actually the front diff as the side gears etc inside that diff are the ones which drive and allow slip to both front axles.
what is listed is the 'transfer' is technically part of the centre differential which also houses the viscous coupling. the small shaft at the RH end of the viscous coupling goes right thru the centre of the VC and gives drive to the RF axle.

It's not my picture

It came from a google search but yeah only posted it so that he could see which part is the viscous coupling and how it's a sealed unit. I think the naming is to show which gears mesh where more than which part is which.

OMG so shiny! · by **Dell'Orto** » Fri Oct 08, 2010 9:03 pm

I read the thread title as Center diff in ST215 welding? and I think its the best option tbh :lol:

by **GTTpower** » Fri Oct 08, 2010 9:26 pm

Dell'Orto wrote:I read the thread title as Center diff in ST215 welding? and I think its the best option tbh

Ha plenty of drag evo's do it, why not :lol:

From watching quite a few caldina's launch at the drag strip, most of them spin the fronts due to the massive weight shift unloading the front.

by **strx7** » Fri Oct 08, 2010 9:46 pm

the viscous coupling is what controls the torque split between the front and rear wheels. If you launch any of the modern 4wd cars with east/west layout, and even wrx's (without adjustable DCCD) have front bias, and if you launch you will get front wheel spin unless they have a locked centre diff

you cant really adjust the split

by **cat007** » Sat Oct 09, 2010 10:48 am

strx7 wrote:the viscous coupling is what controls the torque split between the front and rear wheels. If you launch any of the modern 4wd cars with east/west layout, and even wrx's (without adjustable DCCD) have front bias, and if you launch you will get front wheel spin unless they have a locked centre diff

you cant really adjust the split

That's fine, except in the wet, and I take of pretty hard in 1st gear (not a full boost launch, or even close to it), the fronts will spin to the point that it pulls like a fwd, i.e. doesn't pull at all, rears don't spin and it just does a massive 'skid'.

Surely it's not supposed to perform that badly? And I'm guessing the only option would be replace that viscous coupling? Which, other than the mission that is pulling the engine/box out of these things, will be a very expensive part...?

by **iOnic** » Sat Oct 09, 2010 3:19 pm

They degrade over time. If yours is that bad then it's probably had a hard life. There are places around that can drain (cut) them and refill them with new silicon oil and reseal (Weld) them but it's not a cheap exercise either.

Ring ATL driveline in Hamilton and have a chat to them - they may be able to give you some advice on what to do. They do some work on viscous units from the Land Rovers at work.

(07) 847 9182

by **sergei** » Sat Oct 09, 2010 3:21 pm

I wander if this viscous unit can be replaces by torsen or mechanical unit (generic retrofitted?).

by **BZG Wagon** » Sun Oct 10, 2010 10:12 am

In mine (at least in the wet and on gravel) the rear kicks out.

Can't say it's ever felt like a FWD.

by **sergei** » Sun Oct 10, 2010 11:20 am

BZG Wagon wrote:In mine (at least in the wet and on gravel) the rear kicks out.

Can't say it's ever felt like a FWD.

I can confirm this with mine ST205 and ST165 (which runs ST205 transmission)

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