The SAGA continues.......
As background, I repowered our 1975 Alberg
37 yawl in 2003 with a Phasor P4-37-05 (37.5 Kubota based engine) with the optional Hurth/ZF 15ma
8 deg down angle trans. I´VE HAD 4 TRANSMISSION FAILURES IN LESS THAN 1500 HOURS ENGINE OPERATING HOURS!!!!! I´m now on my FIFTH transmission!! The last failure occurred back in December, 2009 after we had checked into Bahamian Customs
at Green Turtle Cay, in the Abacos, Bahamas
The first (original) trans failed at about 300 hours; the second at about 600 hours; the 3rd at about 250 hours; and the 4th at about 225 hours!! All but the second and last were covered under warrantee by Hurth
- but they won´t talk to me anymore - they say there´s something wrong..... I should say so!!! - even though the previous installation
of a new trans was performed under warrantee by a certified ZF tech, who called his boss in Annapolis
stating ´there´s nothing wrong with this installation - alignment OK, etc. etc. I´ve done the installation on all the other failures myself - (I´m getting pretty good at swapping trans and can do it in about 4 hours (with numerous ´ouch marks´ on my hands and arms!).
The problem in all 4 failures was slipping clutches (in the forward position). The trans specs exceed the engine HP/torque/rpm specs. I´ve rebuilt the trans which was not covered under warrantee, and the forward clutches (8 stack) were considerably worn, along with the ´forward´ thrust washer, which was badly worn.
I´ve been told by a Phasor rep that it appears that Hurth/ZF changed the design of some internal parts about the time we repowered, and that they had ´lots of failures´, and subsequently switched to TWIN DISC transmissions. Of course on my initial failure (and subsequent failures), Phasor told me it was a "Hurth/ZF" matter and take it up with them!!
When I installed the previous transmission, I thought perhaps the original damper plate was too "rigid", and installed a "R&D" damper plate which is a bit more flexible, but it appears that didn´t help much. In my opinion, Hurth/ZF trans are a bunch of ´C--P´
Anyway, anyone have similar failures of the Hurth/ZF 150 down angle trans??? I´m in the Bahamas, and just installed my "spare" transmission, and will probably have the clutch
pack replaced (which are worn along with the thrust washers as in previous failures) in the recently failed transmission so I can (hopefully) get back to the US and home to the Chesapeake in the spring. Have no complaints with the Kubota engine - it runs great!
When I get back home, I plan to install a Twin Disc trans, although they don´t make a down angle trans in my horsepower range, which will take a bit of ´re-engineering´.
If interested, go to the following website for photos and writeup of a previous failure (cut and past the below web URL).
INSTALLING A NEW TRANSMISSION DAMPER PLATE* IN SHEARWATER By Tom Assenmacher
Tom aboard S/V SHEARWATER on Man O War Cay, Abaco