Tight 620 crankshaft

[Anonymous-0]

As I was replacing the tachometer gears I wanted to turn the crank, seemed tight. I also have the the radiator out so no resistance on power steering, hoses/lines are off. Same thing with the governor shaft out. So I removed the plugs, same thing, so the took crank cover off and rods are loose on crank, then took rod caps off and still the same. Was wondering if the mains are the problem, since they are discolored compared to the crankcase, yellow crankcase to a light green main bearing housing. I was driving this tractor prior to tear down and had good oil pressure. With the flywheel cover off and using a 16 cresent wrench the flywheel moves free a couple inches back and forth but is tight as you make a complete turn and always has the 2 inch back and forth where ever you stop. Belt pulley spins easy by hand. Guess I looking for a little info if I should keep going or this is normal for a 620, since the A's, B's and 60's I've worked on before I've never noticed this. thanks chris

 

[Mike M]

There has been alot of talk lately about 620-630 models having a rubber packing swell shut where the oil pressure feeds the main bearings.
So many have seen this I'd sure be inclined to tear yours apart for a look. I have a 530 and a 720D that I'm kinda worried about too. I should remember to check my parts books and see if these use the same set up.

 

[Anonymous-0]

Could there be something in the first reduction cover that could cause some dragging? The more I move it back and forth it feels like its in there since the crankshaft rotates back and forth free a couple of inches. chris

 

[gtx1967jewison]

yes. the gear for the pto is very similar to the 1st reduction gear, between it & the maincase. it turns all the time whether pto is engaged or not.

 

[GlenT]

Here's the link to what Mike M mentioned. I'm going through checks on this on mine. I hope this isn't your problem but if you are going to pull the first gear reduction housing, you might want also pull the right main bearing housing to check this:
http://www.ytmag.com/cgi-bin/viewit.cgi?bd=jd&th=324348

Also, my ball bearing JD7664, which is on the end of the shaft where the first gear reduction gear is, and which is under the little cover in the first gear reduction gear, was very worn and noisy when spinning it by hand. You may want to check this ball bearing.

And, if you are this far in, you may as well replace the oil seal in the right main bearing housing. It is National part number 475953. I got mine from JD but you may be able to get the same thing cheaper somewhere else.

Finally, you may want to check the right main clearance. Let us know what you find out.

Just friendly suggestions.

 

[Mike M]

If your pto gear shifter for the gears, not the foot pedal for the clutches is engaged this would cause a drag from turning all that pto stuff. Try kicking it out of gear. Little metal stub lever sticking straight up and a little bend in it by right hand side of gear shift tower.

 

[Anonymous-0]

The pto lever makes no difference, looks like the frg cover is coming off. thanks chris