[DeTomaso] Gearbox singing noise

[ASSHAUER, HARTWIG]

Bonjour from France,

I had been asked by private mail many times to provide an update about my attempt to fix the singing noise of my Pantera gearbox. Instead of answering individually here is the status to all those who are interested in this topic:
Just before Christmas I had removed the gearbox out of my car mainly to change the shaft seals. In conclusion, it is possible to change those seals but you need to be conscious about two important items: 1) When you replace the paper gaskets of the slide flanges you need gaskets that have EXACTLY! the same thickness (in my case 0.15mm). If not you will change backlash (between crown and pinion wheel) and preloading of the taper roller bearings and create quite a mess. 2) Be aware that the two long tension bolts have also an influence on the taper roller bearing preload when tightening those bolts and you do not have the correct size shims installed!

Before having changed the shaft seals I had checked the backlash between crown wheel and pinion gear and the taper roller bearing preload. I found that somebody had already worked on the gearbox before since I found the crown wheel wire locked and the shaft seals where already changed at least once before. In line with the ZF maintenance manual I found the original backlash marked on my crown wheel which is 0.20mm, but I measured a significant higher value. There was also no preloading of the taper roller bearings. I did some measurements and calculations and found that I had to add one shim of 0.18mm to get very close to the 0.20mm backlash and the specified range of taper roller bearing preloading. After I had reassembled the gearbox parts and added the one shim I crosschecked backlash and bearing preload and found them as specified. I installed the gearbox last week and it turned out in my case that the high screaming noise at low torque is gone! There is still some remaining gearbox noise but overall the noise level is significantly reduced and perfect for me. I drove the car during the weekend on a longer trip and there was no issue. The noise from the gearbox did not change and gearbox temperature was as usual.

I almost forgot:  "Bonne annee" (Happy New Year) like we say in France.

Brgds
Hartwig
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-------------- next part --------------
   Bonjour from France,


   I had been asked by private mail many times to provide an update about
   my attempt to fix the singing noise of my Pantera gearbox. Instead of
   answering individually here is the status to all those who are
   interested in this topic:

   Just before Christmas I had removed the gearbox out of my car mainly to
   change the shaft seals. In conclusion, it is possible to change those
   seals but you need to be conscious about two important items: 1) When
   you replace the paper gaskets of the slide flanges you need gaskets
   that have EXACTLY! the same thickness (in my case 0.15mm). If not you
   will change backlash (between crown and pinion wheel) and preloading of
   the taper roller bearings and create quite a mess. 2) Be aware that the
   two long tension bolts have also an influence on the taper roller
   bearing preload when tightening those bolts and you do not have the
   correct size shims installed!


   Before having changed the shaft seals I had checked the backlash
   between crown wheel and pinion gear and the taper roller bearing
   preload. I found that somebody had already worked on the gearbox before
   since I found the crown wheel wire locked and the shaft seals where
   already changed at least once before. In line with the ZF maintenance
   manual I found the original backlash marked on my crown wheel which is
   0.20mm, but I measured a significant higher value. There was also no
   preloading of the taper roller bearings. I did some measurements and
   calculations and found that I had to add one shim of 0.18mm to get very
   close to the 0.20mm backlash and the specified range of taper roller
   bearing preloading. After I had reassembled the gearbox parts and added
   the one shim I crosschecked backlash and bearing preload and found them
   as specified. I installed the gearbox last week and it turned out in my
   case that the high screaming noise at low torque is gone! There is
   still some remaining gearbox noise but overall the noise level is
   significantly reduced and perfect for me. I drove the car during the
   weekend on a longer trip and there was no issue. The noise from the
   gearbox did not change and gearbox temperature was as usual.


   I almost forgot:  "Bonne annee" (Happy New Year) like we say in France.


   Brgds

   Hartwig

   The information in this e-mail is confidential. The contents may not be
   disclosed or used by anyone other than the addressee. Access to this
   e-mail by anyone else is unauthorised.
   If you are not the intended recipient, please notify Airbus immediately
   and delete this e-mail.
   Airbus cannot accept any responsibility for the accuracy or
   completeness of this e-mail as it has been sent over public networks.
   If you have any concerns over the content of this message or its
   Accuracy or Integrity, please contact Airbus immediately.
   All outgoing e-mails from Airbus are checked using regularly updated
   virus scanning software but you should take whatever measures you deem
   to be appropriate to ensure that this message and any attachments are
   virus free.