Getrag Input Modification

[ellis93]

Ok I was talking to Mr Mark the other night, inquiring about a used input before I bought a china unit. In our conversation he brought up the idea of enlarging the lube orifice for the pocket bearing,which I thought was a grand idea. As I've tore into and rebuilt my rag I've thought about doing something a little more radical.

If you look here,you'll see a fairly tiny slot,ONE slot for lube to reach that horrid pocket bearing. I'm GOING to at least open it up on the inside to match the outside machining grove
Inside pic


Ok here's my thought,if ya'll think its crazy say so.
I want to turn the input 180 degreas and cut another slot in it.


Only possible down fall I can see is maybe weakening it for fourth gear,seeing as fourth is direct.
Any thoughts?

[ahale2772]

I think its a grand Idea

[CumminsPower59]

I would say go on the second opening, since it's going to be 180 degrees from the orginal, and if its going to be the same size, I don't see why that would be an issue. From the looks of it, there shouldn't be any structural issues with doing so, I believe only good can come from it with more lube going to the pocket bearing

[ellis93]

So you don't think I'd rip the butt end off when I tow with it I haul some mean loads.

[ahale2772]

I dono... no way to tell really.

When you increase the radius, of any circular piece, it is inherently stronger. hence I think it is still going to be stronger than the input shaft (splined part) itself.


I coullllllllllllllddddddddd work up a FEA on solidworks, and actually virtually test it.... but that would take a few serious hours, and im bogged down with work untill next week, I dont know if you want to wait that long...

but im willing to give it a try...

[ellis93]

I appreciate that alex but I'm putting it together tomorrow night cause I've gotta go get a new old tractor sunday. I'm in the thinking it would twist that nose in two before that back would break

[ahale2772]

I agree... I say you try it


whats the worst that could happen? you get stuck in the middle of nowhere, on a hill, towing a huge load?!?!?! no big deal....

[ellis93]

Shoot, with this trans,I take that risk every time I pull.

Don't sound like your very sure of my idea

[ahale2772]

I do like the Idea, and I still think the input would twist off before the back half.

if you want to give me some quick measurments, I can do a few silly calculations to make you feel better.

if I had a aproximate cross sectional area of both areas, I could figure out which would take longer to break... even under shock loading

[ahale2772]

thing is, the splines on the input dont provide much strength at all, besides just shear strenght so that the clutch splines dont shear them off.

all the strength is in the base of the splines, and thats not much more than 1 inch...if that....keep in mind the center of a solid bar Bears NONE of the rotational strength under torsion




hence why a willys jeep has a solid shaft for a driveshaft, and a new pickup has a large diameter hollow tube... the bigger the radius, the strongger the piece.

[ellis93]

I'll take the measurments in the morning when I'm around it. I'll post it up asap. Thanks alex

[ahale2772]

Yup, no problem.

try and get me a measurement of what it would be like if you sliced the input at both points, Know what I mean?

thats some pretty easy stuff thats right out of the book, force over area, yet the big issue is shock loading, which is also in my textbooks, so I should be able to get you a Max rotational tourque that each piece should handle

[ellis93]

Alex, the shaft diameter is 1.230,measured here:


The outer diameter of the surface were the slot is, is 2.770. Measured here:


Inner measurement is 2.275 measured here:

[ahale2772]

Ellis, just remembered I have an input here that I can take measurements off.

[Horus]

Great topic. I have a few thoughts/questions.

So nobody is producing an American made input shaft anymore? Does that go for the nv4500 and 5600 crowd too?

I've seen the idea of machining the input to accept a race for the pocket bearing. Does anyone have a part # for a pocket bearing and race? Seems like a great way to keep an original German shaft in place after a rebuild.

I cannot wrap my head around machining more oil grooves into the input. If anything I would be more motivated to weld up the one it comes with. If I'm not mistaken we overfill our Getrags to keep the upper bearings submerged partially in oil. This includes the pocket bearing. The input shaft is always spinning. I don't see how any oil could make it through the slot and into the bearing before it is wicked away by centrifical force. The oil has a far better chance of getting into the bearing if it is pooling against the bearing assembly on the mainshaft side.

Maybe if you spotted and drilled some small holes in the saame area and angled them through the shaft at about a 45 degree angle. If they were angled toward the direction of rotation they might act to pull the oil through as the shaft spins, like an impeller.