What busted you box?

[Cosmo Dude]

In an effort to consolidate the knowlege of all the broken gearboxes out there 'WHAT BUSTED IN YOUR BOX, we know that power and or abuse did the damage.

Please contribute pictures were possable.

Rod

[BigBoyLemonade]

According to the gearbox place mine was cause to flat shift or hard release on the clutch which then weakend the teeth and then when I accelerated slowly round the corner it just let go... then made a tinkering noise.. then I drove it a little more and the noise became a clunk then I stopped driving the car

I have 112.5kw @ 11psi on a conservitive dyno (approx 10-20kw too low)

I also have 18" wheels which I have noticed that most ppl that break their boxes have 18's

[Trav]

I also have 18" wheels which I have noticed that most ppl that break their boxes have 18's

It is not necessarily the fact that you have 18" rmis, but the overall diameter of the new rim and tye combination. Take Stock for instance: Diameter is about 596.1mm (185/65 R14). To keep your diameter the same you would need to be running 225/30 R18. If this is not the case, then you start to put all sorts of extra strain on all parts of the running gear, right back up through the gearbox, as it will take more torque (Force) to turn the wheels. This then is amplified when having a turbo, as it really kicks in the force through the drive train.

This is the same for 4x4's, it is all well and good to put bigger rims and tyres on to give you height, but not when you start breaking stuff.

[BigBoyLemonade]

you cant get 18x5.5" wheels that I know of so it is the 18" wheels...

Also chrome wheels are a lot heavier

[pr1mo]

30 profile tyres OUCH! ehehe nah i noticed a significant performance increase going from 18"s back to 17"s taking that step back allowed me to keep my overall diamater the same as stock too :)

cheers mike

[Trav]

you cant get 18x5.5" wheels that I know of so it is the 18" wheels...

huh?? width?? nothing to do with width. Go back to the old physics rule of F=ma and T=Fd

F: Force
m: Mass
a: Accelleration
T=Torque
d: distance from pivit point

d in this case is radius of your wheel (ie haf diameter)

What wheels are you running tony?

[Dogo]

i agree i think the weight would put stress on the gearbox.

i dunno whats affected my box. quick gear-cahnges, split cv boots, very low oil etc i reckon may have played a part. not than mine is broken. It was making a wierd scraping-like noise in 1st,3rd and 5th recently, but after a major service it seems to have gone away.

i have another question tho ...

Do u ppl use gears to slow down ? I wonder if that puts stress on the gearbox ?! i dont do it. Im in neutral when slowing to a stop.

and leaving it in gear when parked ? would that affect the box too ?
especially if like pr1mo u remote-start ur car in gear ;)

[kyra]

Davo... if you can recall, i did the same thing late last year... started with car in gear... new front bar and too much dosh later... :oops:

I do agree in theory that the bigger the wheel, the heavier the wheel, hence forcing the gearbox/clutch combo to work harder due to more stress.

Primo, how much of a difference between 17's and 18's??

[JynX]

I use a combination of gears and breaking to slow down. Never had a problem with my gearbox in the 3 years Ive had the car.

[TURBO MAZDA]

Even these so called Dog Boxes that are aspose to be unbrackable, well let me tell you there not unbrackable, my mate has a 2000 model wrx with a fulldog box in it. and he still broke 3rd.

[ABC]

haven't had a problem with my box yet touch wood.
Don't use the gears to slow down. Stick it in neutral and brake unless I need to really brake in a hurry or have the boat on the back or something.

Much cheaper to replace brake pads or discs than worry about the extra load you are putting on the whole engine and driveline.

my $2c.

[BigBoyLemonade]

I have 215/35/18

Width does matter because you would have more grip (force) because they are wider, if you dont it will just spin the wheels and when you have a turbo it doesnt matter what size rims you have you still spin the wheels but width is where you get your grip from. more grip = more force doesnt it

Correct me if I am wrong

[ABC]

Agreed Tony. more grip = more force ~ to an extent.

The problem arises when you start to turn something that is bigger in diameter though.

Imagine you're the engine and your turning a driveshaft with a 15 inch rim on it (lets forget about tyres for now). Its going to be reasonably easy to turn it around right?

Well, lets imagine that you've whacked on a wheel that is now 20 inches (because 20's are full sick). Even if the wheels are the same overall weight, its going to be harder for your to turn the driveshaft because the weight is further from the centre.

Is this making any sense? I'm all confused. Time for a lie down. :?

[pr1mo]

Primo, how much of a difference between 17's and 18's??

bigmal is probarbly the best person to answer this question. feel free to take mine and daves car for a test spin to compare rides

cheers mike

[Rupewrecht]

my car hasnt been turboed long enough on the road for the gearbox to break. LOL :lol: :lol: :oops:

but i must say, it's vastly superior in shifting that my old one. much more positive shifts, and probably less notchy. but then, my old one had done 130,000 kms

fyi old was was aug 95 box (BA 2), current on is a dogbox based on a gearbox from the 97 update astina.

aparently it's a dogbox with close ratio billet gears, but still shifts like a normal one, which leads me to think it's still got the syncros (and wouldn't that make it only a half-dog?). but as 5th is also a close ratio gear, it means i'm doing higher than normal rpms on the freeway, which can be a pain

from memory (what eric told me) was that it was sourced by Protech to some guy that makes them for PAC among others.

whoever built it paints all his gearboxes Ford blue (more or less), as that's his trademark.

oh, and i'm running on 17's. i think i'm glad that the 18's werent available in my rim when i got them now...

[Trav]

I have 215/35/18

Width does matter because you would have more grip (force) because they are wider, if you dont it will just spin the wheels and when you have a turbo it doesnt matter what size rims you have you still spin the wheels but width is where you get your grip from. more grip = more force doesnt it

Correct me if I am wrong

Agreed on the more grip, but force itself will remain the same - _however_...

Force and torque are related to the physical setup at all the turning points. Width does not play a part in this, _but_, what will happen in the case of wider wheel is that the you increase the amount of time that these forces are acting on the system. This relates to the coefficient of friction and the friction content of the two surfaces in contact.

Reverse the system - The amoutn of torque required to _cause_ a wheelspin will be 'higher' on a car with more surface contact (wider wheel), but the amount of torque required to push a wheel of same mass and circumference will be the same no matter the width.

As stated before F=ma, so if you increase you mass (ie more rim and rubber) then yes the force increases. I would be going with one of the original comments that alloys and lots of rubber will a more contributing factor than width.

That said if you increase distance (ie radius) then that would be bad as the forces required to move the wheel now are a lot higher..

Well, that's my Phisics lesson for today, tests will be on Tuesday next week - Have a great weeked, and don't forget to study... :P :P

[JynX]

Well a wider tyre will have more mass anyway.... although probably negliable in the overall system.

[Cosmo Dude]

In an effort to consolidate the knowlege of all the broken gearboxes out there 'WHAT BUSTED IN YOUR BOX, we know that power and or abuse did the damage.

Please contribute pictures were possable.

Rod

I know that grip and rotating mass will put more stress on the drive-train. My box is becomming notchy and I've recently replaced my CV joints, too many full lock and full power turns.
What busted in your box, third gear has been an answer. If I was to go to an engineer I'd need more info. :!:

Rod

[BigBoyLemonade]

Goto http://www.Fordlaser.com/

look in 323

They have heaps of discussions on gearbox stregthening

[pr1mo]

rod,
i was at autostyle last tuesday discussing that very matter. he said hed get back to me and took my details. still nothing tho


cheers mike

[BigMal]

Problem with Fordlaser.com is its 99% regurgatated heresay and only
1% fact. You would probably get as good if not better advise from a
gearbox shop.

Regards

Mal

[ABC]

So what you're telling us Dan is that its a mongrel-box or a bitch-box :lol: :lol: :lol:

[joely]

Both width and height make a difference as it is the area of tyre that is in contact with the ground.

The increase in size creates more traction which is what puts pressure on the gearbox.

Useless fact: Did you know that leaving your hand on the gear knob whilst driving also contributes to wear?

I don't know much about gearing down to slow vs breaking. would like to know more though.