Is this gearbox casing scrap ?
Turbo Mini Forums

I think I already know the answer, but I thought I'd run it past the knowledge here first...
Stripping down a friend's gearbox to put in a SCCR gearset, two of the three center bearing retainer bolt holes are lightly cracked.





Is this a scrap casing, or will it live to fight another day ?

Metric is for people who can't do fractions.

The crack can only get worse. I'd find another if you can.

I figured as much - as this is to go under a warmed 1330 I've got another case to use.

Wonder if it would be okay for a std 998 ?

Metric is for people who can't do fractions.

i wouldnt for the same reason Tom said, maybe it could me tigged up and re drilled and tapped?
but how much would it cost for another case? not alot if your re building it anyway

Yes i moved to the darkside

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The cracking in the lower hole only occured as a result of the top one cracking first.

It may not be scrap just yet.

I have them welded and completely fill in that top hole (It usually ends up with that section choped out then filled in with weld). They can be difficult to clean prior to welding, but it can be done.

Then The casing is re-machined for the Third Motion Shaft Bearing, squaring off the transfer case gasket face and clocking it up from the First Motion Shafte Bearing Tunnel (hope that makes sense).

The old guy that used to do them for me had a mutha of a lathe and he spun the whole casing. Regretably he's dead now. The 'new' guy does him in his 5 axis mill - so far so good.

I have found that the casings actually end up considerably stronger than any standard casing.

I've done probably 25 or 30 casings this way now and never lost one yet.

The other thing I do on re-assembly is I NEVER use any of the stupid shims for the 3rd Motion Bearing and I use Bearing Grade Loctite on the bearing itself. Everthing possible to anchor that bearing from even thinking about moving.

Good luck with it.

Edited by mowog on 2nd Apr, 2010.

mowog, its scrap considering the wealth of A+ gear casings available at a cost that doesnt justify the time, effort and expense in what you suggest. Perhaps in Australia, yes.

I agree with you Sprocket. Maybe in 10/15/20 years time it will be worth the effort. But not at the moment in my eyes.

As I'm not really restricted on storage space I think this one will be going to the back of a shelf, to get covered in dust and dug out in 20 years time when there are none left.

Thanks for the advice guys.

Metric is for people who can't do fractions.

Send it to China and get someone there to make more of them in special Chinese Aluminium lol


Well...you never know, they might be able to re-produce the casing in a stronger material for a sensible price. How much would a billet that size cost ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

about £2000