Gearbox casing broke off.

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JAP63

JAP63

E III Recaro Pilot
Joined
Oct 9, 2005
Messages
2,073
Location
Gold Coast
Ok this is weird people.

The other week im driving,go through a roundabout a little quicker than i should have perhaps,i straighten up,smell gearbox oil burning and stop.

Get out and look,underneath the car is pissing out Gearbox oil,i tow it home thinking ive popped the drive shaft out.

Get underneath for a look and next to the crossmember theres a hole in the gearbox,i can see the bottom Front diff gear..hole was around the size of a 20 cent piece but oval...

So wat the F*ck happened?

i have the piece,found it on the road,it was in one piece,i have a feeling it was pushed from the inside out..as i feel if anything were to hit it it would have shattred the piece and it wouldnt have been in one piece still.


anyone had this happen to them?
 
when my gearbox had a hole in the casing it was caused by a gear tooth breaking off and floating around untill it got caught and wedged and then blew a hole in the casing whan it seized.

another reason given to me by ralliart is excessivly lowered cars can have the gearboxes crack open from the stress of the driveshafts at the incorrect angle from being too low
 
Ditto the last post. Lost count over the years where split/broken casings have been caused by a broken tooth dropping down into the diff ring gear , and trying to fit thru a 20 thou gap ! In our rally boxes, a special insert seems to stop most of the debris from dropping down. In the majority of cases, 4th gear had broke. Usually it was only a problem if we ran more than 1.2 bar boost on a stock box. Keeping on top of shimming and the correct preloads on the input/intermediate/output shafts kept the boxes alive a fair bit longer. Most stock boxes I pull apart leave a lot to be desired in their preloads.

Cheers Mike
 
blackvr said:
Ditto the last post. Lost count over the years where split/broken casings have been caused by a broken tooth dropping down into the diff ring gear , and trying to fit thru a 20 thou gap ! In our rally boxes, a special insert seems to stop most of the debris from dropping down. In the majority of cases, 4th gear had broke. Usually it was only a problem if we ran more than 1.2 bar boost on a stock box. Keeping on top of shimming and the correct preloads on the input/intermediate/output shafts kept the boxes alive a fair bit longer. Most stock boxes I pull apart leave a lot to be desired in their preloads.

Cheers Mike
Click to expand...

Are you saying the boxes have a problem of chipping edges of teeth because of inadequate clearances/preload?

If this is what happened to my car should i expect the gearbox to fail majorly sometime soon.

Is the breakout usually in the same spot every time..? ie. under the diff casing in the centre..

Thanks for the help.
 
Yep yep....

This happened to me........ So much so that my gearbox was pushing off the motor when ever i pushed the clutch in and the car stalled...... This was because the previous owner had some gearbox work done and the was only 2 bolts holding the gearbox on........... Most old team4g members would remember the Heathcote cruise when I blew my gearbox. Shat itself in a big way.

Chris
 
Yes I remember, and thank your friend for me...... I drove clutchless from Heathcote to Bendigo (about 40kms or so) to my mum and dads place and then to precision brake and clutch in Bendigo which lead to a 2.5k repair bill. New clutch, gearbox, bell housing and all the other shit that goes with it....

DjB
 
YUP! :(

It happened to YOUDA's gsr when the centre diff blew.

See the thread " The launch is mightier than the gearbox" :wink: :lol:

Hmmmm memories :p
 
Hey mate,

Im in the same boat as you..my gearbox was buggered to start off with, but I never knew why..

A few days ago I went to take the box out from the engine...took off the bolts for it to drain - but funny enough..nothing shot out. Anyway, thought we would top it up and GOD damn F&*KN...all the fluid just pissed out from the bottom...had a good look and jesus..there was a 7CM long X 1CM wide crack. I guess the reason for the crack was pretty evident from the turbo setup and happy go launches lol
 
phaser said:
Hey mate,

Im in the same boat as you..my gearbox was buggered to start off with, but I never knew why..

A few days ago I went to take the box out from the engine...took off the bolts for it to drain - but funny enough..nothing shot out. Anyway, thought we would top it up and GOD damn F&*KN...all the fluid just pissed out from the bottom...had a good look and jesus..there was a 7CM long X 1CM wide crack. I guess the reason for the crack was pretty evident from the turbo setup and happy go launches lol
Click to expand...

7cmx1cm...well f*ck me dude,u couldnt have described it better.
seriously,it sounds exactly the same size as mine,right next to the crossmember and you can see the botom diff gear yeah?

i have a bloody standard turbo and i have this problem....
Mind you when i drained the oil just before it happened it looked like champagne coloured mettalic 2 pak paint,no shit,i pulled particles out of it with the magnet off the back of a speaker.
:!: :!:

bit of nulon teflon and now its like new... 8)
 
Pull the box out, open it up and have a look.

Mine cracked the box by the front diff, right round from the back to the top, with a large hole on top.

Upon further inspection discovered one of the bearings on the intermediate had completely disintergrated - all that was left was a mangled piece of the bearing cage, and 3 rollers, the rest was spread throughout the box as a champagne coloured paste (as you mentioned) and small chunks of metal.

One of the rollers had (as blackvr4 said) tried to go through the gap between the crownwheel and the casing, scored a deep groove round and punched it's way out at the top.
 
If you dont have the right preload/bearing crush ( usually results from bearings wearing over time), then under heavy load ie ballistic launches, the gear cluster shafts tend to move apart. The gear teeth arent meshing as the designer intended, and consequentlly more load on a smaller gear surface area. Then bang, a tooth fractures , drops off, and much unhappiness follows ! Obviously, if a bearing fails, the above happens in a more extreme way.

Cheers Mike
 
So in no few words my box is on the way out.
Great. *tears well up*

i repaired the hole.
i used a file to size it back into the spot and used Devcon Aluminium Casting repair agent.
worked a treat.
 
when mine cracked open i used sellys needit putty for steel repair,put new oil in and the car amazingly drove untill i hit the motorway where it must have overheated the box and at 100kph the gearbox broke the bottom casing off and the box locked up straightaway sending my car into a violent 360 spin

be careful if your attempting to drive it,theres a reason there is a crack in it
 
NZVR4 said:
when mine cracked open i used sellys needit putty for steel repair,put new oil in and the car amazingly drove untill i hit the motorway where it must have overheated the box and at 100kph the gearbox broke the bottom casing off and the box locked up straightaway sending my car into a violent 360 spin

be careful if your attempting to drive it,theres a reason there is a crack in it
Click to expand...

I tried the same thing! :lol: didn't take it on the highway though...

drove/shifted fine aside from the whineing noise (sounded like straight cut gears) - upon opening it up, bearing surface on the shaft was chewed up to hell.

If the case has a crack/hole innit, something inside is broken, pull the box and fix it now before you end up having a scary moment like NZVR4 - or at the very least trash all the other parts in the box. :?
 
Yes i agree.
Thing is,it is driving fine.
Changes fine.,has absolutely no noise at all.
I wouldnt even know there was anything wrong.

I do get ur drift though.

I think the Devcon is a fair bit stronger than that selleys stuff too
 

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