Cracked Gearbox - disaster!

This was a Ford Escort gearbox which had been cracked underneath & was leaking oil. It was brought to us complete (just the gearbox, not the whole car!) & still with oil in it
Could we weld it up?.......
One problem was that we didn't know how thick the casing was so couldn't run the risk of using too much power & burning a hole through the casing & couldn't grind out the cracks for fear of going through. That exacerbated the main problem, that the cracks were dirty/oily & that though the outside of the casing can be cleaned, the inside of the casing was still oily. Welding over the cracks just drew the dirt & oil out & contaminated the weld.



This can be seen here as sooty discolouration & holes in the weld.

Sometimes you can get away with it by cleaning the surface again & grinding the weld off and going over it again. The "dirt" floats to the top of

the weld pool so it gets removed when you grind the weld off (in theory - if it's not too bad).

In this case, the contamination just kept coming through.

The weld continues to grow & still keeps cracking.

The final complete mess! Full of holes & craters. Still cracked, still leaking - a complete waste of time.

The correct way to do this would have been to strip the gearbox completely so that the casing could be thoroughly cleaned inside & out, the cracks could be ground out to remove any dirt/old oil in them & it could be welded on both sides to ensure a good weld. Then rebuild the gearbox.

But that would have cost more than buying a secondhand gearbox, which is what the customer ended up doing & we should have told him to do in the first place!

You live & learn.