Construction Equipment in General and Gear Lubrication

While one should  not go contrary  to the  recommendations of the  supplier of construction equipment, practically all enclosed gears  on such  machinery  can  no  doubt  be  serviced with SAE 80  or SAE 90  EP or  MP gear oil. An  exception  are  worm  drives which should be  lubricated with a  compounded  oil  of SAE  140  grade. The use of certain mild EP oils is permissible for the lubrication of worm drives provided the oil supplier so advises. Air and oil filters require the same attention as in the case of tractors. Also drain periods on any construction equipment should be established at a maximum of 1000 hours. It is best to drain immediately after operating and while the gear boxes are warm. If the discarded lubricant is very dirty, flushing of the gear compartments before adding fresh oil is desirable. Open gears will be found on many pieces of construction equipment. For example, large shovels, cranes, drag lines, concrete mixers, etc. The  recommended lubricant for  such  gears is a residual  type  having  a  viscosity of 1000 SUS  at  210 degree F for cold  weather  and 2000 for  warm  weather. If the machinery  is to be used  under wet  conditions, the lubricant should  contain additive which  will  insure that  the oil  adhere to gear  surfaces  when  water is present. Better  still  these  open  gear lubricants  should contain both  EP  and  rust  inhibiting additives. Exposed gears are lubricated as required, often on each eight hour shift. If  railroad  equipment  is used  in  construction, the  tractor  motor gears  can be lubricated  with  the heavier  grade of open  gear oil. 

Wheel Type Tractors and their Gear Lubrication

According to  Caterpillar, transmissions of a  few  models of wheel  type  tractors  require series  3 motor oils in an  SAE  30  grade above 32 degree F  and  in an  SAE  10W   grade  for  lower  starting  atmospheric  temperatures. The  transmission  lubricant  suggested  for  most  models of  wheel  type tractors  is a multipurpose type  gear oil conforming to MIL-L-2105. An  SAE 90  grade  is  recommended for  starting  temperatures above 32 degree F and  an  SAE 80  grade  for lower  temperatures. Below -10 degree F it may be necessary to dilute this latter grade with kerosene.

The  same MIL-L-2105 type of gear oil  and like  grades  are  suggested  for all models of wheel  tractor differential  and final  drive  compartments. It is recommended that transmission oil filters be changed every   250 hours, except in the case of three models where the period is 500 hours. The  suggested  oil  change  period  for both  transmission  and differential  and final drive  compartments  of wheel  type  tractors is 1000 hours.

 Similar tractors of other makes, as well as allied equipment, such as motor grades etc., will probably require similar types and grades of gear lubricants. However, it is better to follow instructions furnished by the equipment manufacturer or supplier.

Troubles Connected with venting of gear cases

Vents are necessary on practically all gear cases. However, such openings may lead to trouble. Thus, with  a  humid  atmosphere and  considerable  change  in  temperatures  of  gear  boxes, moisture will  enter and  condense, thereby  increasing  the possibility of rusting. Also dirt may enter through such openings. On  automobile  manufacturer actually  experienced  the  entrance of  both  dirt  and moisture  through the vents  in  differential  housings. The  correction was  to  extend  a house  from  the  vent  forward  with  the open  end  placed  on the frame, under  the  body and  facing  toward  the side  of  the car. A location for  the  opening  was chosen where  the  least  throw off from  the  tires  would  the present. If  the  intake  of  dust  or  dirt  is  material, the  use of air  filters is  suggested. Such precautions are taken in the case of machines operating in very dusty atmospheres. Thus, most tractors use filters on vents of gear cases. However, this adds another problem in that such filters must be kept clean. Suggestions have been  made  that  gear  cases  be kept  under  slight  pressure, thus  preventing  entrance of  contaminants. However, this is impractical in most cases. Installation of  filters  containing  silica  gel  on  vents  from  gear boxes has  been  suggested. While this would remove moisture, the value would depend upon the frequency of renewal of the absorbent.