Problems in Connection with Flushing of Gear Cases

 Different problems may arise in connection with flushing gear cases. First the used oil should be removed from the case as  completely as  possible so that  contaminants  are also  removed  and none  of the Oxidized  oil  remains to act  as a catalyst  for the  fresh oil. In so doing, if a volatile solvent is used, this should also be removed completely. Very little of a solvent is required to reduce the viscosity of gear oil, and naturally this is undesirable. Further the  gears should not  be left  without  a coating  of oil  for even a short  period because  rusting  will take place  under  such  conditions. Also  the gears should  not  be  operated  without  a coating  of oil,  even though there  is no load. Troubles have been encountered when gear cases were washed out with chlorinated solvents. 

                                                                 

After fresh oil was added, corrosion developed because some of the solvent was trapped in the case. The best correction for this problem is not to use such a solvent. In fact the safest course in flushing gear cases is to use prepared flushing oil. 

Reduction of noise,vibration and shock by gear lubricants

Gear lubricants, particularly those of high viscosity, will act as cushions and thus reduce noise, shock, and vibrations of meshing gears. However, it must be kept in mind that even the most viscous products are not correctives for poor mechanical conditions.

Mention might be made that Cardillo,^14 in an analysis of “Initial Axle Noise” in automobiles, concluded that it is a resonance problem and apparently lubricants or lubrication plays  no part in abating  this noise .A different noise effect has occurred in automatic transmission and limited slip differential mechanisms of vehicles and in both cases has been corrected by the use of oiliness additives. The degree of oiliness must be carefully controlled since, if deficient, the clutch operation will be rough and cause chattering or squawking but, if excessive, the clutch may slip. Mention will be made of some of the suggested additives for this purpose in a latter section