M35 Rockwell Axle Cutaway Training Aid pics

[rustystud]

Anyone know how the ring and pinion get their lube? I thought it just splashed around in there, but it would have to make its way through a small or-face to do so. Is that top section supposed to have its own G.O.? I have trashed 2 ring and pinions with both having the same issue(pinion slop from bearings going bad, I think). I'd like to keep the third one in good shape if possible, I'll only have one more spare!

I've rebuilt tons of these units, (literally tons ! get it ? tons ?) Anyway the ring and pinion get there oil from splash. The oil is carried up the Bull gear and is squished out by the Drive Bull gear (the smaller straight cut gear). It works quite well actually. You can take a complete pumpkin unit and suspend it over a pan of oil. Then turn the input shaft and you will see what I mean about the oil riding the bull gear up to the other gears.
The picture is me in 1982 rebuilding a "2 Speed Double Reduction Rockwell Differential". I cannot remember the truck it came out of. I never took the units out. They came to me on pallets. I had to rebuild 2 of these units a day and a small transmission (like a SM465). Complete tear down and cleaning and rebuild.

 

[Floridianson]

Thought the bull gear pulled up the oil to the upper housing. Then from there the upper has a hole and it returns down that hole past the pinion and back to the sump. That is why you must be careful how you put the gasket on the input side of the pinion seal housing so as not to block off the hole. Also the pic shows the old type of CV joint and if you have that old style then you pack the knuckle. If you don't have the CV type you don't need to pack the knuckle.

 

[Recovry4x4]

Lucas oil had these little display dodads that had gears in it that you crank. These were designed to let you see hownlube climbs a gear abd how theirs climbed better. It's facinating and amazing at how well gear oil can climb straight cut gears.

 

[gimpyrobb]

I believe the G.O. creeps up the gears, not sure it creeps sideways through this big bearing! Rusty, know how this assembly comes apart? Press fit?

 

[DavidWymore]

I replaced my center third member with the bed off. I ran the new one with the top cover off in the shop with the wheels up and the rear axle disconnected to test. Vid in link below is 2nd gear idle. Any higher gear, and a lot of oil went everywhere in a hurry.

http://vid142.photobucket.com/album...E-1B1D-424F-B7BE-DBB8FDA96EDA_zpsudnlubez.mp4

I also filled the axle with oil by dumping it in the top cover hole. It drained down into the diff more slowly than I poured it in, I could see the top part of the diff fill up, I would have to stop pouring, then the oil would drain down into the housing, and there was a delay between the top being full and when it ran out the fill plug on the side.

So to sum up, those gears pump a lot of oil up to the top, and it drains down pretty slowly, so lube shouldn't be a problem....unless mine was just that way because the drain back hole is restricted...which might be a good thing for upper gear and bearing life.

 

[gimpyrobb]

Thanks.

I guess I'll have to fill a diff and make a video to see if it pulls the oil up from the housing. These gears were pretty dry compared to the other parts in the housing.

 

[DavidWymore]

Thanks.

I guess I'll have to fill a diff and make a video to see if it pulls the oil up from the housing. These gears were pretty dry compared to the other parts in the housing.

Hmm...maybe something is wrong...maybe a shim washer to large in OD or a bearing shield/seal left in place blocking oil flow...?

Mine pumped lots of oil quickly, and when I shut the engine off, it took a bit for it to drain down. I believe that when it's running, the top is basically full, or should be. I haven't had one apart yet, but that will likely change before long.

 

[rustystud]

I believe the G.O. creeps up the gears, not sure it creeps sideways through this big bearing! Rusty, know how this assembly comes apart? Press fit?

Yes, it is pressed on and off. The military used a special puller, I always just used a bearing splitter and a press. The oil doesn't just creep it sprays ! Believe me when these units are running oil is going everywhere !

 

[welldigger]

Yes, it is pressed on and off. The military used a special puller, I always just used a bearing splitter and a press. The oil doesn't just creep it sprays ! Believe me when these units are running oil is going everywhere !

These lube themselves just like my mud pump does. The angle and direction of the gear teeth isn't by accident. They spray the gear oil to a specific point.

 

[gimpyrobb]

We'll see, I plan to look into this much further. I have found other sites that guys have had issues with this top section being dry. I'd just like to find a reason why. Its such a pita to pull these and swap them out!

 

[welldigger]

We'll see, I plan to look into this much further. I have found other sites that guys have had issues with this top section being dry. I'd just like to find a reason why. Its such a pita to pull these and swap them out!

Inspect the shafts and housings for weep holes. Maybe they get clogged sometimes. Can't say for sure since I haven't torn one down this far.

 

[gimpyrobb]

Yup. I plan on taking the ring gear/spur gear apart to look-see around. That is where the oil will have to flow through to get lube to the pinion bearings.