Recommendations on Lube Oils
The oils listed in LSN 935 1410, ...1420, ...1430 are a selection of lube oils recommended by L + S for use in cylindrical, bevel and planetary gearboxes. CLP industrial gear oils, motorcar transmission oils and HD motor oils meet the requirements specified by L + S as mandatory. These recommendations are based on applicable product information and many years of experience in this field.
The lube oil brands (mineral oil, synthetic oil, or motor oil) are primarily selected by the operator. In this context, logistics play an important role. The recommendations are not meant to provide quality standards for the individual lube oils.
All oils listed are compatible with one-pot paint material (not nitrocellulose lacquer) L+S uses for inside paint coatings as well as the standard elastomers of NBR and FPM (depending on application temperature). As regards mineral based gearbox lube oils an oil bath temperature of +85°C should not be exceeded. For short operating periods peak temperatures of +100°C are admissible, but it should be noted that these may considerably reduce the useful life of the lubricant. Continuously prevailing higher temperatures will reduce the operating viscosity significantly and lead to premature aging of the lubricant. If an admissible temperature limit is exceeded the oil molecules chemically decompose and cause smell, deposits and residues in the system. If higher temperatures are to be expected or higher continuous temperatures are experienced in operating practice, synthetic oils based on polyalphaolefins (PAO) are to be used that feature a considerably flatter temperature-viscosity characteristic curve.
A mandatory requirement specified on the nameplate and/or in the operating manual are the viscosity indication and the special notes.
If the viscosity requirements are not met or a gearbox lube oil other than listed is used the responsibility for technical suitability of the lubricant lies solely with the Operator. The use of lubricants not meeting the equality standard described below may result in L+S' warranty obligations becoming forfeited. It is expressly pointed out that any lubricant manufacturer or supplier is responsible for the quality of its products, eg with respect to impurities or differences between individual batches.
NOTE: L+S' gear teeth calculation according to DIN 3990 (including micro-pitting determination to FVA No. 54) shows the required breakdown-load stage (SKS) for the oil. If a breakdown-load stage SKS of > 9 is determined here, a note must be included in the operating manual saying that the lubricant selection is restricted to brands featuring a "high" micro-pitting (frosting) load carrying property.
NOTE: The maximum and minimum application temperatures of individual gear oils may deviate significantly with regard to the technical parameters of "flashpoint and pour point". Relevant data and properties of the gear oils must always be taken from the technical data sheets issued by the oil producers.
As pointed out by the lubricant producers, the products listed are available under the same tradename on a world-wide basis and have comparable technological characteristics.
1.1 Synthetic oils on polyalphaolefin basis-PAO
Synthetic oils have a higher viscosity index (VI) than mineral oils and are thus able to reduce the influence of temperature on viscosity. Although the polyalphaolefin-based synthetic oils listed (Column LS 3) can be mixed with mineral oil at any desired ratio, care should nevertheless be taken to limit the amount of residual mineral oil in the gearbox casing to 5 to 10% to avoid clouding and additive precipitation.
1.2 Synthetic oils on polyglycols basis-PG (presently not permissible for L+S gearboxes)
NOTE: In view of the fact that synthetic oils on polyglycol basis may be incompatible with the paint coat, standard seals and oil sightglass materials employed, these lubricants must not be used without prior consent obtained from the gearbox maker!
Mixing polyglycols with mineral oils is strictly prohibited.
1.3 Quickly biodegradeable oils on synthetic-ester basis-HEES
Under certain conditions, quickly biodegradeable lubricant oils (synthetic ester-HEES) not listed here may also be employed. Results of various research projects, for example FKM No. 051950, VDMA Data Sheet 24 569 as well as applicable experience gained by seal manufacturers and oil companies indicate that quickly biodegradeable oils may be incompatible with certain seal and gasketing materials and paint materials or may reduce the friction characteristics of multiple plates. If such oils are to be used, special materials (not L+S standard materials) may be needed that have to be tested to ensure they are compatible with the oil.
NOTE: Before using quickly biodegradeable oil (first filling or brand change) consult with the gearbox manufacturer!
2 LSN 935 1410 "Lube Oil Recommendation CLP ISO VG 22-680"
The mineral oils listed in this shop standard specification meet the minimum requirements given in DIN 51517 T.3 for CLP oils. They contain constituents that improve corrosion protection and ageing resistance as well as reduce wear in the mixed friction range (extreme pressure additives). When subjected to normal FZG testing A/8, 3/90 to DIN 51354 T.2 a breakdown-load stage of min. 12 is achieved. When subjected to a FZG micro-pitting test as per FVA No. 54/IV these oils reach the micro-pitting (frosting) load carrying property category "high" (SKS 10) or at least "medium" (SKS 9).
Other oil brands meeting or exceeding CLP requirements are included such as hydraulic oils HLP or synthetic oils HC.
LSN Specification 935 1410 describes ISO viscosity categories. Low-viscosity oils are almost exclusively needed for use with multiplate brakes. They have been tested by the multiple-plate manufacturer for compatibility and friction behavior.
Not all of the lubricants listed in this shop standard are suited for any conceivable application. For that reason, L+S Groups LS 1, LS2, LS 3 were established.
NOTE: The Design Department hast to specify the required L+S group! This group will be indicated in the operating manual and/or on the nameplate. When selecting an oil brand care must be taken to ensure that all requirements of a given L+S Group are met. In the event an oil meets requirements of additional L+S Groups this lubricant can be used as well.
LS 1: Aggravated FZG test:
Even when FZG tested under aggravated conditions (test A / 16,6 / 90-double peripheral speed) these oils have reached the properties of breakdown-load stage 12.
L+S Identification for a lube oil passed aggravated FZG testing of viscosity ISO VG 100 CLP 100 LS 1.
LS 2: Lube oils compatible with multiple plates
These oils have been tested for friction characteristics and can be used without friction value impairment in gears fitted with wet multiplates.
The maximum viscosity with wet multiplates has been restricted to ISO VG 220 because higher viscosity values negatively influence actuation.
L+S Identification for a multi-plate compatible lube oil of viscosity ISO VG 100 CLP 100 LS 2.
LS 3: Fully synthetic oils (polyalphaolefins PAO)
When replacing mineral oil by polyalphaolefin-based oil 5 to 10% of the mineral oil are allowed to remain in the casing after draining. Mixing both lube oil types is perfectly allowable if this mixing ratio is observed.
NOTE: However, PAO oils tend to foaming when mixed with residues of preservation oil as used by L+S. Therefore, prior to initial filling of a preserved gearbox the unit must either be flushed out or a mineral oil is to be used as running-in oil.
L+S Identification for a synthetic lube oil of viscosity ISO VG 100 CLP 100 LS 3.
3 LSN 935 1420 "Recommendation for Motor Lube Oils HD SAE 30, 40, 50"
The motor oils listed are unigrade oils to DIN 51511 (non-doped or just moderately additive-treated) that will not lower the friction value in multiplate couplings (sintered linings or organic lining). The FZG load stage (DIN 51354 T2) is min. 11 and the micro-pitting (frosting) load-carrying property of these oils correspond to breakdown-load stage of min. 9.
L+S Identification for a motor oil of viscosity SAE 40 HD SAE 40.
4 LSN 935 1430 "Recommendation for Motorcar Transmission Oil HYP SAE"
This shop standard specification lists unigrade and multigrade lube oils for motorcar transmission units to DIN 51512 and assigns them to API classification GL 4 and/or GL 5. The selection of these lube oils is based, inter alia, on a defined, 'actual' viscosity (ISO viscosity) because the SAE viscosity parameter commonly applied to motorcar transmission units may appear in several ISO viscosity categories (see following diagram). It is to be noted that micro-pitting (frosting) test results are not yet available for these oils so that they must exclusively be used for L+S mobile gears.
NOTE: When selecting a HYP lubricant brand the viscosity specification on the nameplate and/or in the operating manual is to be compared and adapted to the lubricant specified included in the operating manual.
L+S Identification for a motorcar transmission oil of viscosity SAE 80W-90 HYP SAE 80W-90.
5 Viscosity Classification Comparison of Various Lubricants
6 Oil Change/Topping up Oil
The life and operational safety of a gear unit is greatly dependent on the purity of the oil employed for lubrication. For the first oil change after commissioning of the gearbox as well as further oil changes the instructions given in the relevant operating manuals are to be followed. The oil volume remaining in the gearbox should be kept to a minimum.
NOTE: When topping up oils or if oils are to be mixed the quality and viscosity have to be carefully observed. Mixing lubricants of different makers may bring down the quality standards even if the viscosity properties coincide. In such a case the lubricant supplier should be consulted in advance to check if there are compatibility problems.
The lubricants listed must never be mixed with other substances. Flushing/purging media or petroleum or other agents used for cleaning the gearbox have to be thoroughly removed without residues left. The unit must again be flushed out before it is commissioned.
7 Abbreviations and Symbols Used
- AGMA American Gear Manufacturers Association
- API American Petroleum Institute
- DIN Deutsches Institut fur Nomung
- EP Extreme pressure
- FKM Forschungskuratorium Maschienenbau e.V.
- FVA Forschungsvereinigung Antriebstechnik
- FZG Forschungsstelle fur Zahnrader und Getriebebau, TU Munchen
- GfT Gesellschaft fur Tribologie
- GL Gear lubricant
- HD Heavy duty
- HYP Hypoid oil
- SAE Society of Automotive Engineers
- VDMA Verband Deutscher Maschinen-und Anlagenbau e.V
- VG Degree of viscosity (viscosity at 40°C in mm2/s
- VI Viscosity index
- API American Petroleum Institute
8 References, Co-applicable DIN Standards
- DIN 51502 Abbreviation used for the lubricants
- DIN 51511 SAE-viscosity categories for motor lube oils
- DIN 51512 SAE-viscosity categories for motorcar transmission lube oils
- DIN 51517 T3 Lube oils "minimum requirements"
- DIN 51354 T2 FZG-gear test rig "method"
- FVA-Nr.54/I-IV Micro-pitting (frosting) load-carrying property category
- DIN 51511 SAE-viscosity categories for motor lube oils
Recommendation of Lube Oils
Viscosity Class ISO VG 220 at 40°C mm/s (cSt) DIN 51519