any big bhp g40s ever done a gear box like this ?

[Oli b]

basicaly the differntal cage broke up and chucked two holes in the casing :S one in the belhousing and one out near the speedo drive
the box is,nt a atv its a 4 speed polo gear box but i think the diffs are the same any way heres the pic

and it ruined my clutch too

[hayesey]

ouch! good effort getting the diff to explode like that

[Oli b]

yeah was a bit shocked it broke like it did :S turns out 4speeds dont like 3 times the power they were designed to have chucked at them are the 5 speed box's stronger then ? as my atv box is in bits atm i got a 5spd from a 1.0 seat ibiza no idea what code it is

[hayesey]

nope, 5 speeds arent any stronger.  The diff part is the same.

[Oli b]

Yeah thats what i thort hmm might take it easy with this one but thats easyer said than done

[hayesey]

I wouldn't worry too much about it.  It's very uncommon for these boxes to fail like that.  I'd suspect either a manufacturing defect in the diff cage casting or some foreign object inside the box jamming the planet gears or something along those lines.  I don't think that's happened purely because of the amount of torque being put through the box.  

They certainly can fail due to power alone but it normally results in bearing failure or stripping the teeth off a gear.  Although it's possible one of those happened and then that actually caused the diff failure right away too.

But on the other hand, the ATV on my car has survived many track days with a plate diff, 194bhp and about 180lb/ft through it.  And The Hayes driving it - (Edited by peteg40)

[Andy]

I've got a few pics of similar things happening to stockish G40s as well as tuned ones. I think if the pinion gears get mashed up the diff can tear itself to pieces, and then exits through the casing. I've had a diff fail on mine, but the car the 'box came from had been bounced off a few kerbs - which I suspect might've damaged the diff as there was enough force to snap driveshafts.

[Yoof]

Polo DSG (Dam Shite Gearboxes) 

[Oli b]

well i striped the ruined 4 speed today to see how bad it was and......

i think a tooth snapped of and got stuck then caused the diff case to break up as this was the only real evidence of its failure or this could be more damage cause by the diff case just giving up

[ereeiz]

A bit of T-cut should sort that out

I've still to pull my box off yet. Nowhere near as bad as that hopefully. I can still drive mine but can't get 2nd without scary noises.

[vwmk3jon]

T-cut?

Liquid metal ftw