Clutch housing, stress cracks or mfg. defects??

[JMBT]

Hello all I got my transmission out the other day. It was covered in 810,000 miles worth of throwout bearing grease. When I got it all cleaned up today I noticed what looks like small cracks in various places all over the inner bell. (see pics)

I am looking for your opinions as to whether they are stress cracks or just manufacturing defects in the cast aluminum.

Thanks, JMBT

[Aussie Steve]

(03-03-2021 )JMBT Wrote:  Hello all I got my transmission out the other day. It was covered in 810,000 miles worth of throwout bearing grease. When I got it all cleaned up today I noticed what looks like small cracks in various places all over the inner bell. (see pics)

I am looking for your opinions as to whether they are stress cracks or just manufacturing defects in the cast aluminum.

Thanks, JMBT

Nothing to worry about. You'll those marks in a brand new housing. Most of them look like small imperfections from the casting method. I don't ever recall seeing one fail unless somethings gone wrong - clutch flying to bits from abuse, loose bolts etc.

[Rawze]

Aussie Steve has it right ...
A lot of that looks like the typical crazing of an aluminum or cast-iron part that cooled too rapidly, or in an uneven fashion. - It seems to be fairly common.