Ctis versus regular axles

[red]

for highway only I'd use the older 5 ton axles because of the cheaper bearings and seals. Remove the outer seal so it will be wet hubs. To get enough oil into the axle (stock fill port by the diff is too low for this) you could drill a new fill plug higher.

 

[Castle Bravo]

On CTIS rear hubs, only the outer bearing would be oil lubed if this conversion was done. You would need to remove both CTIS inner (middle, really) hub AIR seals and then plug the CTIS air passage port in the hub in order to oil lube the inner bearing. Yes, can be done. Not possible to retain CTIS and oil bath rear hub inner and outer bearings simultaneously. There are 4 total hub seals on CTIS hubs. Outer-most and inner-most are oil/grease seals. The middle 2 are air seals for passage of air from spindle to hub as it rotates. No opinions? You're no fun...

There is no outer seal on the M939A2 rear axles, the outer bearing is an oil bath setup in the stock configuration.

 

[infidel got me]

I gutted my ctis, brass plugged hub, and replaced seal with regular drum seal and have no problems. No heat issues and everything seems to be lubed/oiled properly with no leaks to report.

74m hows my pink a/c bracket? It's hawt out and your sister wont ride in my truck till I get my a/c installed!

 

[74M35A2]

First batch of 8.3L A/C bracket kits expected to ship out tomorrow. And sorry, but A/C is not the reason she won't ride in your truck.

 

[Csm Davis]

for highway only I'd use the older 5 ton axles because of the cheaper bearings and seals. Remove the outer seal so it will be wet hubs. To get enough oil into the axle (stock fill port by the diff is too low for this) you could drill a new fill plug higher.

So how high would be high enough?

sent from my decrepit fingers

 

[Csm Davis]

There is no outer seal on the M939A2 rear axles, the outer bearing is an oil bath setup in the stock configuration.

So the A2 housing may have higher oil level than A1?

sent from my decrepit fingers

 

[74M35A2]

Sounds like it. Is that the reason they went with the flat bottom on them, to reduce the quantity of oil needed to tumble down the axle tube? I would guess as long as the ring gear is picking it up, it would get slung everywhere and travel down the axle shaft and tube, eventually reaching the bearings. This explains why my rear outer hubs run cooler than my fronts though. You can tell I have not had mine apart, as I didn't know the A2's were already oiled outer. I'll be doing the opposite, and converting the rears of mine into greased outer, as I am making a trailer from the back half of an M923A2, and pulling the drive axles and eventually differentials out of the housings, and retaining the CTIS, so making them the same as the fronts essentially.

 

[Castle Bravo]

So the A2 housing may have higher oil level than A1?

sent from my decrepit fingers

I do not know. The lube order doesn't differentiate between the different axles and says they all take 3 gallons of Gear oil.