Scooby Luke

thats an intresting bit of info mate...

the scoob is un-driveable at the moment and is sat on my driveway... i cant take corners properly... Was you car this Severe??

I have got the wheel off tonight to get the tyre replaced tomorrow. Ill give that a go round the block, if no diffrence (which im sure it wont be) ill give dave a ring and see what i can do about it. Maybe i could try a rear diff first before looking at getting the box out to look at the center diff.

The mechanic i use says that a rear diff ratio miss match could cause the problems im having but how can that be if the center diff is open?? surely that would allow the rear wheels to turn at diffent speeds to the front and wouldnt affect turning?!?

Any diff experts want to clarify?

911

Bloody hell!

500

The problem does sound like it is a ratio difference. My understanding is that the wheels will always turn at the same speeds in a streight line, the centre DCCD is like a clutch, either sending more or less power to the front wheels, not different speeds. by driving it as it is, you are going to break somthing pretty quick.

Before you take the diff and box out to check the ratio's, do you have the same tyre size on all 4 corners?

If you do, take the diff and box out asap and check

Scooby Luke

Yes i do have the same size wheels on all four corners.

I had an idea while i was laying in bed last night...

If i get the car up on axel stands to do a John Style test but this time put some white tape on the tyre i should see if the ratios are diffrent buy how far the tape has moved on the front & back wheels.

Weather or not this test would hold up in practice i dont know... Worth a try??

John Stevenson

Luke that wouldn't work, any difference in load, even slight, with the wheels in the air will mean they will turn at different speeds.
I have to say that a ratio mis-match sounds more than plausable to me. I recently bought a V4 Type R box (broken one) and the rear diff that came out of the car it had been installed in. Box was as it should be at 4.44, rear diff was 4.11.
Before doing anything rash like taking things out, what model is the box ? TY75xxxxxx number on the bellhousing next to the starter.

---john---

Jay m A

iTrader: (2)

Yep I have to agree, I've also been missold a rear diff that according to the gearbox model and car it came off - was supposed to be a 3.9 lsd, turned out to be a 4.4 lsd

It was a good job I span the prop flange and counted the revs before installing it

911

It is easy to count-out the rear diff for the ratio using tipex on the crown (drain oils obviously) and turn the prop till the tipex shows itself again through the drain hole, but the front is impossible without a strip?
Graham

RRH

went with quite a bang during a sprint at Aintree; i'd just gone through the speed trap at and indicated 140 (so probs about 120 ) but it did show all the symptoms mentioned by the thread starter.

It was my own stupid fault for trusting third party info, I thought it was just a nice tight diff. fortunately I had a spare box, and the RA gearset really was too short for 350/350ish

Scooby Luke

Hiya John… Just been out to look at the number on the box. It’s a TY754VB1CA.


Had a look on a couple of websites and looks like this is the stats…

Code 1st 2nd 3rd 4th 5th FINAL Diff Code
TY754VB1CA 3.083 2.062 1.545 1.151 0.825 4.444 F,G (RA)

Diff codes:

F,G (RA) :

front helical LSD (R160)
Mechanical cable type 2way LSD (R180) Rear
DCCD Center


Are there any numbers or anything on the diff to tell me what type/ratio it is?

Scooby Luke

Update:

I have spoken to Dave at API who thinks the rear diff maybe to tight. Im going to get the diff off at the weekend and check to make sure its the right ratio using 911's trick of counting the teeth through the oil drain hole. If it is ill send it off to API for them to look at.

Will keep you guys posted on the outcome.

Scooby Luke

911

You will be in safe hands.

Scooby Luke

Update:

Had a look at the diff today and it would seem that the rear diff is the right ratio. Going to get the diff taken off over the next week and sent over to Dave at API.... hope he can work some magic on it and get it working for me.

Will let you know what happens.

Scooby Luke

Update....

Rear diff is now with API so im kinda hoping dave can sort the issue!!

911

Dave has a transmission guy Rob. He /they will resolve the lot and you will be back on the road in no time.
Fixed all my probs for me!

Scooby Luke

API had the diff apart on friday.... seems that some how it has a plate missing!!!

Although this is a big problem and will need to be replaced it may not be the reason for the issues im having. The plan is to fit the diff and see if that solves the issue. if not i guess the box will have to go off to API.

APIDavid

iTrader: (4)

This is a tricky one to try and second guess what might be going on.

The plated LSD involved here, is a very early version that we have not seen before. It has an unequal amount of plates inside and at least one plates- worth of slack inside it. IE., one plate is missing. We have no spare plates.

What I am thinking is that; As-is the diff should not work, because it cannot generate any pressure to lock the drive shafts side to side. Therefore, it should just be slack and not locking, unlike the complaint on this car, that suggests that it is too tight and permanently locked.

What may be happening is that the slack is allowing the planet gears to move out of mesh and jam, creating the fully locked sensation.

Anyway, we are going to fit a replacement later style LSD with a known torque setting and see what happens. If the lock up still persists, then it must be the gearbox rather than the diff.

What cannot be escaped is that the original diff has a part missing inside it and cannot be right if left alone. So no money or time wasted.

Time will tell whether it was the diff or is the gearbox

David APi

Shark Man

Perhaps the plate was removed in a vain attempt to make the diff more open to try and resolve the locking up problem now mentioned? - Which could suggest that the symptoms were there before it was taken out the donor car, and the diff was fiddled with to try and fix it......

Time will tell

... I presume the 'box doesn't have a front LSD fitted?.....

Scooby Luke

Cheers for the Summery David.

The diff is being fitted on thursday evening so i will report back on friday and let you guys know what i find.

APIDavid

iTrader: (4)

Probably not, but by no means certain. You can tell by jacking the car up and rotating a front wheel. If the other wheel goes the opposite direction to the one being turned - No LSD. if they both rotate the same way then LSD fitted SIMPLE.

David

LUKE, I guess you mean summary? The weather is anything but summer -y

Sorry about that

Scooby Luke

LOL.... thats the one David

Scooby Luke

Got to the garage on friday evening expecting the car to still be broken after the diff was fitted from API.... BUT... Its Bloody works!!!!!!!

Cant belive it... i was sure it was the gearbox that was giving me the problems! Still cant really explain why the car was doing what it was doing but obviously it had somthing to do with the fact the rear diff was screwed.


Thank you so much for everyone who posted and helping me understand what was going on and thank you to API for getting the diff sorted.

Now i need to learn how to use the DCCD... allready have had the back end go up a hill in the wet. lol. Any tips??

911

Easy:
Talk to John F on 22B.
I did and he sorted the sweet spot to say the least.

APIDavid

iTrader: (4)

Phew!!, another one we got away with, how long is our luck gonna last ??

Good luck Luke, enjoy it now.

David APi

swisstonihasher

Hope dont mind me jumping in here but I'm about to go down DCCD route and wonder that location on the box, is it the same wiring location for all DCCDs? If so, you can wire it without having to get underneath the box yes?

Scooby Luke

Didnt see this post before. We wired it when the box was in but up on a lift. Not sure about gettin access to the wires from on top.