Odd crack in 6.0 FF housing

Bruce Amacker · March 6, 2013

I'm teaching in Oregon, and a student has multiple 6.0 FF housings cracking where the "strut" between the OH and FF housing attaches to the OF housing. Trucks are '05 ish F550 manual trans (no DMF), one truck broke 4 of these housings. Any idea why? I'm thinking a harmonic imbalance, but student says they run and drive fine.

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Brad Clayton · March 7, 2013

That's a doozy. Is it cracking in such a way that things are leaking?

lmorris · March 7, 2013

I have seen one do that and was leaking oil. No running concerns or abnormal vibrations. Not sure on what trans was in it though.

Bruce Amacker · March 7, 2013

Yes, seepage leaks are the first sign, then wet leaks. The multiple failures are the odd thing- it's a PTO bucket truck and runs the PTO an hour at a time on higher idle speed....

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lmorris · March 8, 2013

I have also seen an intake manifold crack where the alternator mounting is. Get it hot enough and it would whistle under full boost.

dieseldoc · March 9, 2013

I have seen two housings crack like this, in that spot. Both were F-550 service trucks with 6 spd manual trans. They had hydraulic drive air compressor and cranes on them. They would seep oil when the truck was running and hot.