Transmission input shaft bearing

Thu Dec 27, 2007 5:11 pm

I just received a new needle bearing for the later style transmission case. This is the one that the end of the input shaft sits in in the rear of the transmission. The bearing is lubricated by splash oil that sits in a pocket and runs down a hole to the bearing. Since it is a caged needle bearing, a hole is provided in the bearing to allow the oil to come in and provide lubrication to this bearing that sees full engine speed from the input shaft. Being the upper shaft, this needs all the help it can get.

Problem is, the replacement bearing from CNH no longer has the lube hole. These bearings were always a little starved for lube, according to what I was told, and I can't imagine they would survive long without the lube hole. In fact I was cautioned that installing a bearing without the hole lined up would be certain death.

My old bearing was not pretty. Visible chunks are missing on some of the needles. So I decided to make a weep hole for the oil. I scribed the center of the case and tried to drill a hole but that was pretty much hopeless. Can't prick punch it and I think the race is case hardened anyway. I used a thin cutoff wheel to grind a slot and then I could use a drill bit. I put a small dab of grease on the bit to help catch the metal. i broke through gently and could not see any damage to the needles. They are caged and there is just enough room in between the bearings so the bit pushes them out of the way. The bearing was catching a little so I took an ultra-small jeweler's screwdriver and "picked" at the edge to bring any flash up and out of the bearing race. it seems to have worked.

i have 4 choices now. Use the shot bearing, use a new one and hope that lube will get to the needles, use the one I modified and hope it does not break down, or find a good used one. I think I'll take my chances with the new bearing with the drilled hole.

This is NOT an issue for tractors under serial number 189613.

Thu Dec 27, 2007 5:29 pm

I used a thin cutoff wheel to grind a slot and then I could use a drill bit. I put a small dab of grease on the bit to help catch the metal. i broke through gently and could not see any damage to the needles. They are caged and there is just enough room in between the bearings so the bit pushes them out of the way. The bearing was catching a little so I took an ultra-small jeweler's screwdriver and "picked" at the edge to bring any flash up and out of the bearing race. it seems to have worked.

Hi Bob. It sounds like a good plan. providing you're positive you have all burrs and chips removed. You'll know in short order if you don't.

Rick

Thu Dec 27, 2007 5:42 pm

One other choice; Mr. GW has a p/n for a simular bearing, the only difference is the ID. The end of the shaft has to be turned down a few thou. I'm sure Mr. GW will chime in soon as to the p/n of the bearing.
8)

Thu Dec 27, 2007 7:06 pm

Donny,
THAT I would like to hear. The shaft surface is not all that great and the clutch spline is a little twisted :twisted: so I see a new shaft in my future. Sure don't want to take this apart anytime soon.


[/quote]
Hi Bob. It sounds like a good plan. providing you're positive you have all burrs and chips removed. You'll know in short order if you don't.

Rick[/quote]

Rick, short of X-Ray, which I no longer have access to, I would have to take it on "blind" faith. It feels OK but I worry about the edge of the hole breaking down.

Bob
Last edited by bob in CT on Thu Dec 27, 2007 7:10 pm, edited 1 time in total.

Thu Dec 27, 2007 7:09 pm

Yes it's a great fix, with a real bearing...Mr. GW where are you.... :lol: :lol:
8)

Thu Dec 27, 2007 7:25 pm

Donny M wrote:Yes it's a great fix, with a real bearing...Mr. GW where are you.... :lol: :lol:
8)


I'm right here!

The transmission for the Gabby project has the bearing conversion. It's a ND 3L04 sealed bearing if I remember right. I centered the shaft in the 4 jaw and trued the shaft with a tool post grinder and reduced it to .787". Just a few thou has to be removed. The sealed bearing should eliminate any lubrication problems for a lifetime. :lol: Keep in mind these bearings are rated for 3800 hours running at rated RPM and load... running slowly and lightly loaded they should last much longer. :lol:

Thu Dec 27, 2007 8:40 pm

Bob, I used George's method on my 49 Cub and it worked like a charm. I can highly recommend it. :D

Fri Dec 28, 2007 8:05 am

What if you removed the seals on the bearing. That would let more lube into it right. In the past with sealed bearings we had problems because there wasn't enough lube in then. Then what was in there would turn to liquid and run out thru the seals which weren't that great.

With all the short lived bearing life talk here its time to change your lubes because its sounds like its not working. Again its time for gear oil with moly isn't it?

Moly; "Eliminates" All Wear, "Reduces" friction, Prevents Galling, Fights Corrosion and its like having an insurance policy against all these things that you'll never need to cash in on. Moly is that good.....and good for your tractor too.

The bottomline is Don't let Things Wearout before there time.....using moly it ain't gonna happen. Were making an investment in the future here by using moly. You think Seafoam is good? Just try some moly...it only gets better.

Thats it i'm ordering my moly gear oil today......

Fri Dec 28, 2007 8:54 am

Go to; http://www.tsmoly.com Then to the consumer section and they have moly additives for gear oils and your engine oil too. I got a moly for every need. I'll use the moly paste during my restoration/assembly of gears and bearings too so it will have a head start on eliminating wear.

If your seeing wear your present lube isn't doing its job so scrap it and get moly...

Fri Dec 28, 2007 10:23 am

The bearing manufacturers really do have the lubrication of sealed bearings figured out. Why on earth would anyone screw them up by removing the seal? :roll:

The problem with the original bearing was two-fold... the rollers running directly on a shaft that isn't especially hard (a worn out bearing means a worn out shaft) and a lubrication system that stinks (crud in the galleys or feed hole means failure, as does improper assembly). If IH had spent a few more cents and used a sealed bearing in the first place it would still be good. Notwithstanding, many Cubs have lived for more than 7 times their design life using the original faulty setup, but that's no excuse. :shock:

Fri Dec 28, 2007 11:16 am

I agree George. I would not touch the seals, especially in this case because there is no lube oil available to the bearing. It think it is a much better approach for anyone that uses the PTO with stationary attachments as this bearing would get nothing for lube without the pinion shaft turning and splashing oil. Art Chester pointed this out to me yesterday (before the sealed bearing was mentioned) that farmers would jack up one wheel and let it spin just to lube the top shaft.
I looked at that shaft as a weak point because it is the bearing surface. It seems to me that this bearing is really just a guide and most of the support load is taken by the input bearing, but a bad surface here means replacing a $95-$300 shaft plus a bearing. The fact that the lube "well" for this bearing was full of ground metal from the difficulties this transmission had in the past certainly helped this bearing and shaft to wear. It is a good place to collect any crud and plug the oil flow.
A bearing with two hardened and precision-ground surfaces that can be replaced is attractive to me when I look at the design.

Fri Dec 28, 2007 11:50 am

I also recall George posting about this on the ATIS forum. But my recollection is that the grinding of the shaft to accept a sealed bearing is for the earlier Cubs. Bob has one of the newer Cubs. Is this procedure applicable to both?

Fri Dec 28, 2007 12:09 pm

The bearing changed in 1954 at 180614 as the the first with the needle bearing. Good question to confirm.

Fri Dec 28, 2007 2:31 pm

We just pulled shaft from "Uncle Bob", who is a '47'. The shaft is grooved where the bearing rides. George, where can I get one of the sealed bearings? I have already talked to a machine shop about reworking shaft to fit a new bearing by welding and turning down to fit. Since I am going to do this anyway, it seems to make more sense to let the machine shop fit the shaft to sealed bearing. My concern is that the ID of sealed bearing must still be big enough to slide over the spline at end of shaft. Isn't that the only way for the bearing to get on the shaft?

Fri Dec 28, 2007 3:28 pm

BIGHOSS wrote:We just pulled shaft from "Uncle Bob", who is a '47'. The shaft is grooved where the bearing rides. George, where can I get one of the sealed bearings? I have already talked to a machine shop about reworking shaft to fit a new bearing by welding and turning down to fit. Since I am going to do this anyway, it seems to make more sense to let the machine shop fit the shaft to sealed bearing. My concern is that the ID of sealed bearing must still be big enough to slide over the spline at end of shaft. Isn't that the only way for the bearing to get on the shaft?


It's a stock bearing you should be able to get from any bearing supplier or even NAPA. Unless your shaft is worn VERY badly it shouldn't be necessary to build it up. The bore of the bearing is slightly larger than the spline (.7874"). According to my notes the ND 3L04 is the same as an SKF 6004. I don't know the suffix to assure you get a true sealed one and not just a shielded one... ask the supplier.