Ooops! -JD450 fuel pump timing gear shaft

I am in the middle of stripping down the engine (4-202 diesel) from my JD450. When taking off the timing gear end (gear train aluminum end cover) cover I noticed that where the fuel pump gear runs, the shaft has moved axially and the gear has rubbed on the inside of the cover ( not too deep though). Looking at the gear itself I noticed that it had moved slightly, so being of a curious disposition, I grasped the gear and pulled lightly towards myself. OOoops, the shaft and gear came out easily, much too easily I think. Needless to say I didn't notice which position the gear was in before meddling, but I am sure it won't be too hard to time it back properly.

Two questions come to mind:

1. Should the shaft and gear slide out that easily? If it shouldn't then that is probably why it has been moving axially with the engine running and causing scuff marks on the cover.
2. I cannot see anyting to hold the shaft other than perhaps, the shaft seal - being that it is in two parts, both facing opposite directions. Is this what restricts axial play or movement? If that seal doesn't prevent the end movement, what does and where is it?

Sorry about the question, but the manual doesn't show too much and being that everything on this engine is well worn, I am trying to find out what needs to be renewed and what doesn't. I do know that the cost is already more than I anticipated and I have a way's to go yet. Hope I haven't got me a money pit.

Thanks in advance, for any and all comments :-))

J.

Thanks for your replies. Regarding the drive shaft for the fuel pump, it came out so easy that it just didn't seem right hence my posting. The manual I have doesn't show too much detail, but enough to do the job.

I looked in the manual after psoting and saw that the wear limit for the drive "tang" of the end of the shaft, is 0.305", with 0.310" when new. I checked mine and it came out at 0.293" across the tang - well below the limit. A new shaft is needed. I checked the inside of the pump from the shaft hole and the driven clutch appears to be alright, the driver part being the badly worn half. I will know better when I take the fuel pump off later.

JD - you mention the parts available for rebuilding/overhauling the pump. Where would be the best place to purchase these - any recommendations?

Yep, seems like this engine work is gonna be a bit on the expensive side. I am glad the JD dealer is allowing me to loan special tools, it will make a big difference. However, it is still going to be a lengthy process to do properly.

Thank you once again for your information and help. Some of my concerns might seem very basic but this is my first time working on these engines. Please bear with me on that.

J.

If so, the shaft simply pulled out. It can go in 2 ways, 180 degrees apart.

There is a "pip" mark near on edge of the tang on the end of the driveshaft, and, if you look WAY down inside the pump, there will be a corresponding mark near one side of the slot the tang fits into. At the very least, the pump seals need to be replaced, and the shaft CAREFFULLY reinstalled, or you will have a diesel fuel-into-the-crankcase leak.