Spicer Speciality Axle Division - Technical Publications
OVERHAUL INSTRUCTIONS FOR TYPE D66 DRIVE HEAD UNIT WITH DIFF LOCK
(AS FITTED TO REAR DRIVE AXLE)
The drive head features an overhung spiral bevel pinion mounted in widely spaced taper roller bearings
which are adjustable by graded spacers.
Drive is transmitted through a heavy section crownwheel and differential assembly, again running in
taper roller bearings, and adjustable by special nuts, running in differential straps.
A variety of pinion and crownwheel combinations are available, covering a wide range of ratios.
A differential lock, operating on the drive shafts, is available as an optional extra.
Very often noises and vibrations originating in other parts of the machine, are mistakenly believed to
eminate from the drive head, with the result that time and effort is wasted on an unnecessary
dismantling operation. Therefore, before fixing suspicion on the drive head, investigate all other possible
sources of trouble. Where a drive head is definitely suspect however, draining the housing and
examining oil for metal particles will aid diagnosis and help to pinpoint any malfunction.
Check following defects and note possible causes :-
Loss of lubricant
Spiral bevel gear adjustment tight, seized bearings
Noise on turns
Worn side gear and pinions
Worn or damaged trunnions
Loss of lubricant
Worn drive shaft splines
Loss of drive
Broken drive shaft
Stripped splines on drive shaft
VITON 'O' RINGS AND SEALS (FLOURO-ELASTOMERS) - SAFETY HAZARDS.
It has been brought to our attention that 'Viton' material used in manufacture of oil seals and 'O' rings,
produces a highly corrosive acid (hydroflouric) when subjected to temperatures above 315° C.
Resulting contamination can have extreme consequenses on human tissue since it is almost impossible
to remove after contact.
We therefore recommend the following procedure when it is necessary to inspect any equipment that
has been subjected to a high temperature i.e. fire.
Visually inspect for any gaskets or seals which have suffered from heat ; they will appear
black and sticky.
If this is affirmed :- Do Not Touch.
Any flouro-elastomer (Viton, Flourel or Tecmoflon) should be considered dangerous but
natural rubber and nitrile are non-hazardous.
If flouroelastomer seals have been used, then the affected area MUST be
decontaminated before undertaking further work.
Disposable heavy duty gloves (neoprene) MUST be worn and the affected area
decontaminated by washing thoroughly with limewater (calcium hydroxide solution).
Any cloths, residue and gloves used MUST be safely discarded after use.
Burning of discarded items is NOT RECOMMENDED, except in an approved
incineration process where gaseous products are treated by alkaline scrubbing.
Manual No. 1785 Issue A
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