879172A39 Mercury SHIFT SHAFT ASSEMBLY

769D (5TR1-UP),
771D (6JR1-UP),
773D (7ER1-UP),
775D (6KR1-UP) OFF-HIGHWAY TRUCKSReference: Diesel Engine Oil SPEC Sheet - CG-4, Form PEHP6046 - 1997Caterpillar CG-4, Preferred Engine Oil, Form LEDQ7315 - 1997Applied Failure Analysis, Principles of Lubrication, Form SEBV0567Problem:
It is becoming more and more obvious, that certain "Fighting Grade " CF-4 engine oils from some oil suppliers, do not seem to be capable to do their job in the above mentioned HEUI engines for 250 Hours, even at a "Low Load Factor". - For the definition of "Load Factor" please refer to ET and the Performance Handbook (Load Factor based on Engine Fuel burn Rate).- For the definition of "Fighting Grade" engine oil versus "Premium Grade Oil", please refer to SPEC Sheet - Form PEHP6046.It goes without saying, if an engine oils service life span is shorter than the oil change interval, hence, if an "Additive Package Crash" occurs before the oil is changed, the result can be devastating and very expensive.I.E. the engine oil has to be changed before it's additives are depleted, plus, the oil has to be able to withstand the temperatures etc. as experienced in these engines for at least the entire 250 hours, and at any given Load Factor.Solution:
We strongly recommend, that if your SOS/infrared analysis indicates that your CF-4 oil does not fully protect your engine for 250 hours, to first shorten the oil change interval until you are sure, your Additive Package is doing it's job fully all the way to the oil change. A far better solution however, is to "push" your end-users to start using CG-4 engine oils, which have a much improved Additive Package, can withstand much higher oil Temperatures before causing any problems in the piston ring are, i.e. - are far superior when it comes to Dispersant, Anti Foam, Anti-Oxidation, etc., Engine Oil Additives. Another obvious advantage of using a Higher Grade/Quality Engine Oil, is the gain in total Engine Service/Wear Life, Optimize Oil Change Intervals etc.. CautionWhen changing to a higher hrade/quality engine oil in a "used" engine, hence, an engine that is neither new nor rebuilt, we recommend the following procedure due to the fact that the higher grades oil more aggressive Additive Package may "clean up" the inside of the engine:- Cut the oil filters open after already 50 hours of operation. Have a good look at possible "sludge", "carbon", in short plugged filters.- Install new oil filters.- Cut them open again after another 50 hours of operation. Look for possible filter plugging. - Repeat this procedure until you are sure the filters are doing their job, hence filtering, during the entire oil change period. Omitting to do this, may result in a worse SOS oil analysis reading after 250 service hours with the Higher Grade Oil then before with the Lower Grade, due to lack of filtration !If you have other, relevant questions in this matter, please do not hesitate to contact the LWL/SOHT Tech. Rep. in 3LCP1, COSA Geneva, Ext.: 4826.COSA LARGE AND CORE PRODUCTS DIVISION COPYRIGHT 1998 CATERPILLAR ALL RIGHTS RESERVED