Camshaft gear

Captkerosene

New User
got a 1939 D with manual start. Runs great but has a few teeth on the Cam gear partially missing. Have a new cam gear but have not been able to find any detailed info on how to change it. Don't think I have to pull the flywheel or crank but haven't found a manual that explains it well. I have several JD manuals, including the one from Yesterdays Tractor but doesn't tell me what I need to know. If I have to pull the flywheel I will have to take it somewhere as I wouldn't be able to do that myself. Haven't been able to find anyone local who has worked on one. If anyone has info on what needs to be done I would greatly appreciate them sharing it with me. The D is a different animal that other 2 cylinder models. Thanks. Really want to get this fixed so I can start restoring it.
 
Not familiar with D's but I would think you'll have to pull the flywheel and the clutch assembly off and then pull the crank out so you can press the old cam gear off and press the new cam gear onto the crankshaft.
 
Never did a D but plenty of G's and A's. Those you can pull the camshaft out without removing the crank. A 70 the crank has to be out or bearings removed and let the crank drop down. You will need to take the clutch off and reduction cover also. Pull the governor out and lower the cam follower holder. Pull the bearings off the cam. You will probably break them doing this so figure on new ones. There are 3 bolts locked to the cam gear with a plate that you need to remove. Turn the cam till the flat spot by the cam by the gear is up and start wiggling it till it comes out. You will need to drop the oil pump shaft also and unhook the oil lines. Gear should come out once the cam is out. That is how it is done on a G or A anyway. If it is the gear on the crank, I have changed them by removing the flywheel and main bearing. Put some heat on the gear and find a spot you can hit the gear with a chisel and drive it off. Again this is done on a G.
 
Thanks for the info. The camshaft gear is keyed in place with a key and two squeeze bolts to clamp it to shaft and secure it. The oil pump resides on the lower right of crankcase and is driven by shaft with gear running off of camshaft gear on the left. I looks like I could release pressure by loosening pushrods, pulling clutch assembly, and sliding camshaft to the right and then remove the camshaft gear from camshaft while still in the crankcase, but not sure. Probably have to remove governor also. The JD manual I have illustrates the A and B but that appears to be quite different from the D. Not sure why the camshaft gear has parts of several teeth missing. Crankshaft gear and oil pump gear are good with no markings on them. I have no idea how long it has run like that but I was able to find a new camshaft gear so why tempt it. Any info on what I need to do is appreciated. It runs now so would rather drive it on a trailer if I have take it someplace. I have a few medical issues so would not attempt to remove flywheel and crankshaft by myself.
Thanks for the help.
 
May I ask, what does the Governer Gear look like?

Is the Governer Gear driven off the Cam Shaft Gear.?

What does the Crankshaft Gear look like?

Is the Camshaft Gear driven off the Crankshaft Gear.?
Bob..
 
the D is the same engine as the G. thats why i was wondering what was so different on a D .
 
Just reading these posts so I went to my I&T manual. The D camshaft is below the crank and the pushrods run under the bores. There is an external bearing cap on the left side under the flywheel but the right requires removing the pulley and reduction cover. It only covers R&R of the camshaft, pulling it from the gear out the right side. Doesn't mention getting the gear out but I'd suspect it would require taking the crank out unless you could reach in from the top and fish it out somehow. I&T has a good cutaway picture at the end of the section.
 
Thanks for all the help guys. I reviewed the I&T manual and I think I can do this w/o having to remove the flywheel. If I do I will have to go to plan B, what ever that may be. Will Be a good winter project. Hope to have it back up and running soon.
 
captkerosene; Your thinking is correct. Get an old I&T manual No-JD-4 for your D; has good information and pictures. The D is quite different than the JD A or G. No governor to come off. Hardest work is pulling off the pulley and the first-reduction gear cover. No flywheel to come off or no crankshaft to come out.. Cam gear is squeezed on its shaft as you said. You can pull camshaft out the right side of the case to free the gear.. If you need more room other than through the top crank case cover, you can pull the oil-pump from under the flywheel.. Not too hard, but labor intense??
 
Thanks for the info. Got a JD-4 I&T manual and think I may have located a bunch of old JD Service manuals. Not sure but would be a big help. Going to try and tackle the project myself. Got a heated shop and lots of time just going to give it a go. Thanks to everyone for the help.
 

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