kt_Engineer

I am not clear on the question. You are right with your statement ""vapor bubble" is both created and destroyed at the liner itself and not the result of being moved about by the circulation of the coolant." As I explained the bubble is formed due to static pressure (vacuum) drops below the vapor pressure of the coolant. Coolant will start bubbling up due to this and will collapse as soon as vacuum/static pressure exceeds the vapor pressure of the coolant. This occurs in couple of milli seconds and is not caused by the circulation of the coolant. Cavitation can also occur in the water pump itself but the cylinder liner cavitation is much more severe.

I did my entire Master's research thesis on trying to simulate cavitation on wet line Diesel Engine cylinder liners at ~1500 Hz in lab conditions. As you mentioned the phenomenon occurs due to cylinder vibration (due to combustion) causing the liner to move away from the coolant for milli-seconds creating a vacuum like condition. The static pressure dropping below the vapor pressure of the fluid causes the coolant to form micro-bubbles (cavitate) which implode when the cylinder liner moves back to its original position. The micro-jets from the implosion travel at high-velocity impinging on the cylinder wall damaging the liner. The additives in coolant thinning out starts cylinder line corrosion eventually. The dual action of corrosion and cavitating bubble collapse accelerates the damage. The biggest Engine OEM in US (who funded the research) created the cavitation in their lab using ultrasonic transducer vibration at 20,000 Hz on test specimen. They tested out different additives to see the improvement of wear on test specimen. Since actual Engine vibration occurs at 1500 Hz the fluids (with additives) developed in lab were not showing identical life improvement (on liner) as was seen in the lab (on specimen). I was tasked with creating cavitation at 1500 Hz and testing out different coolant additives to see the improvement. This was something I worked on over 25 years back.

Unusual to see fatigue failure on the helix thread side of the thru-shaft. The helix thread pumps oil to the powerdivider through the hollow tube that goes around the thru-shaft. Thru-shaft is the easiest part to install. Mack Road train trucks in Australia carry couple of these in the cab as they sometimes snap them in out-back going over dry river-beds. The slipping inside you felt was power-divider doing its job. The cam power-divider is designed to send 3 times the torque to non-slipping axle when it senses slip on one axle. The inner and outer cam are spinning at different speeds when you hand-spun the yoke. I would recommend checking the inter-axle shaft/angle and U-Joints and make sure they are in good condition and will not fatigue the shaft again.

There are different variations for axle housing rating & suspension rating. Mack makes 11mm & 14mm wall thickness stamped steel axle housing along with 3 versions of cast iron axle housing (23k lbs with Mack proprietary spindle obsoleted in 2012-13 also one with R-series spindle, 26k lbs with Mack M2 series spindle and 32.5k lbs & 42.5 k lbs M3 series spindle). The 11mm is typical for on-highway usage but can be allowed at different ratings with different suspensions based on applications. 44k lbs was a special version allowed for some Municipality with a tag axle that allowed 11mm housing to be used at higher rating (taking loads and others into consideration for that application). It was later allowed for some other applications with the 11mm lighter weight axle housing.

You are always rated at lowest rating of the axle housing GAWR, Suspension and tire rating. In this case you are good upto 38k lbs GAWR (assuming your tires are rated to 38k lbs too - which should not be a problem IMO). This a 11mm axle housing and cannot be loaded to 46k lbs.

Depending the vintage of CRD92/93 (the diff side gears have different version of splines) you might need to change the axle shafts. axle shaft lengths are identical.

Yes. CRD150/151 will bolt on to the axle housing on CRD92/93. Depending on vintage of CRD92/93 you will need to change the axle shafts.

Yes, CRD921 can be used in combination with CRD93. "1" in CRD921 & CRD931 stands for Inter-Wheel Power Divider/Limited slip differential between wheels. You will need different axle-shafts if you are mixing and matching.

It is proprietary Mack axle based on CRD95/96 carrier series. It is identical to S652 axle but with upgraded GAWR capacity to 85,000 lbs (tandem; 42,500 lbs/axle). The new Link/Raydan 85,000 lbs suspension is matched with this axle.

93"1" is designation for IWPD - Inter-wheel power divider i.e CAM limited slip differential. 93 is standard differential. Since CRD92/93 did not have inter-wheel diff lock, the IWPD is better choice for slippery conditions (though it is useless if one of the wheels is spinning on ice).

CRD202/203 is interchangeable with CRD92/93 and fits in the same axle housing. CRD202/203 is higher load carrying axle series (upto 180,000 lbs for linehaul) while CRD92/93 is good upto 130,000 lbs.

Mack did not introduce diff lock until 2009 so this definitely doesn't have one.

CRD92/93 is old version that has been in production for 40+ years and replaced with CRD150/151 in 2009. The newer axle has slightly better design and rating and capable of pulling upto 150,000 lbs for linehaul applications. You can try to find closest ratio CRD92/93 but will need to ratio match with smaller or bigger tires so as to not burn up inter-axle powerdivider.

CRD150/151 was introduced in 2009 to replace CRD92/93. This is the first Mack axle series with Differential Lock option (i.e fork/clutch to lock left and right wheels). CRD921/931 is the Interwheel power divider/Limited Slip Differential (identical to Inter-axle differential with peanuts and cam differential) between wheels. CRD92/93 doesn't have differential Lock. CRD150/151 is also offered with Limited Slip differential option and referred to with CRD1501/1511 designation. Interwheel Power Divider differential does automatic torque biasing with 3:1 torque sent to non-slipping wheel but if other wheel is one ice with zero traction then you are going nowhere. With diff lock you should be able to move even if one wheel is on ice. Diff Lock is extremely inexpensive compared to IWPD (Inter Wheel power Divider) version

If you rebuilt T318 and T318LR then T2180 is not a bad choice. T318 is evolution of T2180 with some improvements. Gear ratios should be very identical.