914A gearbox too hot?

[Disciple4123]

Last week I rebuilt my 914A mower deck gearbox (72") because it had two bearings seized. I thoroughly cleaned and dried the remaining parts, and the two other bearings were in good shape as were the gears. Everything went together smoothly and Ifilled it to the fill hole with 90w140 gear oil. When I mow it does not have operational difficulties, but within ten minutes it gets too hot to touch. This is when mowing high grass, or previously mowed grass. I do tend to mow vigorously, at full RPM, near full engine loading. Is this normal? I also pumped a total of six pumps of grease in each of the spindles in two sessions, and still have no grease visible from the bottom when the blades are removed. How much grease does it take to fill a blade spindle that has been run dry by the previous owner?

Thanks,
Eric

 

[Soundguy]

As for the grease on a dry part.. how much does it take? It takes as much as it will hold without bulging seals.. if a sealed unit.. or if it is a system where excess can be extruded.. then you should pump till some extrudes.

When the gearbox gets hot.. try to rotate the driveshaft by hand.. make sure it is not beginning to bind.. perhaps the other bearings are beginning to seize?

Soundguy

 

[Disciple4123]

I am concerned with the grease that it may look about right after, say, eight pumps, with slight seepage from the spindle bottoms. And then when it heats up and spins it may put out more grease and hit the belt. For now I think I may just run it a few more times with what's in it.

With regard to the overheating gearbox, I check it for free turning after shutdown and it is very smooth. Neither bearing shaft has play or roughness. I can only assume that the heat is normal at this point. The case has no heat dissipation fins, but one screw on pressure breather.

Thanks for all the advice on my issues.
Eric

 

[Soundguy]

For what it's worth.. most gearboxes do heat up quite a bit.

I think the grease issue will be fine if you see a bit of seepage.. that means grease is all the way down. A few mainenance pumps after or before use should be fine.

good luck

Soundguy

 

[RickB]

Old mechanic's rule: if the paint isn't lifted off a gearbox, it isn't running too hot. Maybe a little extreme, but you get the idea. Dry spindles may take 20-30 pumps of grease. Overgreasing will usually force excess to the blade side, not the belt side.

 

[Bird]

</font><font color="blue" class="small">( Old mechanic's rule: if the paint isn't lifted off a gearbox, it isn't running too hot. Maybe a little extreme )</font>

A few years ago, I had a Kubota dealer tell me almost the same thing about the hydraulic fluid in the tractors (actually, he said they didn't worry about heat unless it discolored the paint), and yes, I thought that was a little extreme, too. /forums/images/graemlins/laugh.gif

 

[hazmat]

Nowadays with affordable infared thermometers - we can get more technical and actually put a number on "too hot".... /forums/images/graemlins/laugh.gif I haven't seen any numbers flowing down from Manufacturers yet. /forums/images/graemlins/confused.gif