Mower deck gearbox oil?

[deeter16317]

I'm going to change the gearbox on my Grasshopper mower deck (PTO drive) with some leftover 75w140 or 85w140.

The gearbox contains gear oil, but the manufacturer doesnt provide a type, and only states to replace when the box fails. The local Grasshopper shop gave me the same line. I'm one who likes to maintain things...and this is a fairly easy drain and refill.

Since its only used in summer (read: warmer temperatures), and contains less than a cup of oil...is there any concern using a common (synthetic) gear oil?

Its just a basic 90* drive box...nothing exotic.

 

[JHZR2]

You're not putting a lot of power through, so I guess the question is of mating surface area vs lube film. I'd imagine that given the speed, power, etc, it is far more benign than, say, automotive application.

I'd say that any lube available would work find here.

 

[Rob_Roy]

I have used 80w90 and 85w140 lubes in mower gearboxes, no issues to report.

 

[deeter16317]

Thanks, I figured as much.

The last few of these mower gear boxes I have opened contained grease, not gear oil. So you can imagine my surprise when gear oil spilled out of the fill plug!

 

[marco246]

The 62" mower deck gearbox on my JD 2305 calls for 80W-90. I use Shell Spirax GL-5. No issues.

 

[car54]

I change the oil on my PTO mower deck gearbox every other season, and it always comes out pretty nasty. The gearbox gets pretty hot under load, so I figured its best to keep it well oiled. I use regular gear oil, whatever I have laying around.

 

[deeter16317]

I just replaced the Driveshaft, with one that has a true spline and not the retangular slip extension. Once I got that swapped out, I pulled the drain plug...oil isn't real bad looking, but it is really thick and draining slow (acts like it has no breather vent), so I'm going to allow it to drain until tomorrow night. It appears as least as thick as the 85w140 I'm going to refill with...I hope its not a specialty oil or a 00 grease of sorts.

I did note that its a Peerless gearbox...

 

[wag123]

ALL of the Peerless gearboxes that I have ever come into contact with use Bentonite Grease. It is charcoal grey in color and has the consistency of pudding. Do not get it on your cloths, the stain will never come out. Do not use gear lube or automotive grease in a gearbox that is supposed to use this! You can purchase it at an outdoor power equipment store. The top half of the gearbox needs to be removed to put it in and it does not need to be changed.

 

[deeter16317]

Originally Posted By: wag123
ALL of the Peerless gearboxes that I have ever come into contact with use Bentonite Grease. It is charcoal grey in color and has the consistency of pudding. Do not get it on your cloths, the stain will never come out. Do not use gear lube or automotive grease in a gearbox that is supposed to use this! You can purchase it at an outdoor power equipment store. The top half of the gearbox needs to be removed to put it in and it does not need to be changed.



This is definitely gear oil, and drained through a bottom plug. You cannot remove the top of the box...the cover is the bottom, which contains the plug.

I filled with 85w140 royal purple tonight.