Thanks for the advice all.
I did speak to ZF again, they said that oil
color would suggest the clutch
was overheated. They said that this is usually because the shifter is not configured to completely engage the gear. I was fully aware of this as a potential problem when I put the gear in in May, and set the shift lever up to that it over-compensated in forward and goes well beyond spec.
My flexible coupling doesn't allow for testing with a feeler gauge because the shaft coupling part nests inside the flexible coupler.
The alignment tests I did were to rest a knife on top of the shaft and put it in gear, I did not discern any vibration or movement at all.
I did not try this at higher RPMs, and the possibility that under load my engine mounts might move and create wobble did occur to me. Honestly the only test I did on that was visual, I just stared at it for a long while while underway. At least visually I could not detect any wobble. I know it's not a proper test, but I felt the alignment would need to be visually discernable for it to be the cause of problems considering the flexible coupleing.
I do shift fast into gear.
The cutless bearing is quite new and in good shape, the prop had nothing on it. I just had it taken off and re-pitched, so now it is totally clean and polished.
ZF are going to send one of their technicians to look at the installation
. Although the poster who went through 5 ZF15s had them out to look at it a couple of times.
I last changed the ATF oil
, and I think I only put 5-10 hours on the transmission since then and the oil is already burned. Unless I'm wrong about the alignment, or the shifting adjustment , the only other thing I could think of was that it just candle handle the load of pushing my heavy boat around. So I am praying that my de-pitching the prop might lighten the load and spare me having to replace yet another transmission.
If it does break again I'll probably put in PRM 80.