Are there such things as "Best Oils"?
Well after many years in this business I can only allude to "in service" performance rather than Specification Sheet numbers and postulations over base oils and additive package formulations
Many years ago when using RoadRanger-RR-heavy truck gearboxes it was a requirement to "re-race" the box and replace selector components at regular intervals. A debate at the time raged over which oil to use, a SAE 90 GL5 gear oil or an SAE 50 engine oil. The maker recommended SAE50, but truck operators used both and with almost equal results
The main RR wear indicators were;
a) "noise" for the bearings
b) gear lever "slop" and mis-selection for the selector mechanism. Most selector wear was caused by the Driver's -collectively- habit of resting their hand on the knob of the 4ft long gearlever for hours on end! This multiplies the load on the selector components which are usually free of load until used for gear selection
Castrol's Synthetic Gear oils and synthetic ATF
A - I commenced using Castrol's Syndrive 50E in RR gearboxes in 1992
B - As well I commenced using Castrol's excellent Syntrax, either 90w-140 and latterly 75w-90, in Rockwell & Eaton axles at the same time
C - I started to use Castrol's Syntrans a GL4 too in various vehicles in 1992, and when Transmax Z ATF appeared commenced using it too
Over the last 12 years I can report a tale of success;
1 - we have never re-raced a RR gearbox since 1992*
2 - we have never replaced any RR oil seals since 1992*
3 - we have never replaced any selector components since 1992*
4 - we have never had a differential failure since 1992*
5 - we have replaced the odd wheel hub oil seal at around 500k - usually a regular job at
IN EACH CASE THE GEARBOX AND DIFF LUBRICANT WAS CHANGED FROM THE MINERAL FACTORY FILL OIL DURING THE FIRST 3K on average
IN EACH CASE THE OIL WAS NEVER CHANGED AGAIN* - SOME RANDOM UOA's WERE TAKEN
* Up until vehicle disposal at 700k
Admittedly RR's technology has improved since 1992 as well
We now use Mobil SHC50 and SHC 75-90 in some vehicles too
It should be noted that the operating range of ambient temperature is from -10C to 50C
I hope this is of interest
Regards
Well after many years in this business I can only allude to "in service" performance rather than Specification Sheet numbers and postulations over base oils and additive package formulations
Many years ago when using RoadRanger-RR-heavy truck gearboxes it was a requirement to "re-race" the box and replace selector components at regular intervals. A debate at the time raged over which oil to use, a SAE 90 GL5 gear oil or an SAE 50 engine oil. The maker recommended SAE50, but truck operators used both and with almost equal results
The main RR wear indicators were;
a) "noise" for the bearings
b) gear lever "slop" and mis-selection for the selector mechanism. Most selector wear was caused by the Driver's -collectively- habit of resting their hand on the knob of the 4ft long gearlever for hours on end! This multiplies the load on the selector components which are usually free of load until used for gear selection
Castrol's Synthetic Gear oils and synthetic ATF
A - I commenced using Castrol's Syndrive 50E in RR gearboxes in 1992
B - As well I commenced using Castrol's excellent Syntrax, either 90w-140 and latterly 75w-90, in Rockwell & Eaton axles at the same time
C - I started to use Castrol's Syntrans a GL4 too in various vehicles in 1992, and when Transmax Z ATF appeared commenced using it too
Over the last 12 years I can report a tale of success;
1 - we have never re-raced a RR gearbox since 1992*
2 - we have never replaced any RR oil seals since 1992*
3 - we have never replaced any selector components since 1992*
4 - we have never had a differential failure since 1992*
5 - we have replaced the odd wheel hub oil seal at around 500k - usually a regular job at
IN EACH CASE THE GEARBOX AND DIFF LUBRICANT WAS CHANGED FROM THE MINERAL FACTORY FILL OIL DURING THE FIRST 3K on average
IN EACH CASE THE OIL WAS NEVER CHANGED AGAIN* - SOME RANDOM UOA's WERE TAKEN
* Up until vehicle disposal at 700k
Admittedly RR's technology has improved since 1992 as well
We now use Mobil SHC50 and SHC 75-90 in some vehicles too
It should be noted that the operating range of ambient temperature is from -10C to 50C
I hope this is of interest
Regards