Am I too OCD or should I flush/clean my SQ480 gearbox?

trikepilot

New member

Equipment
B2620HSD w/ LA364 BH65, 48in Bush Hog, Bush Hog rear blade, Woods 5ft Box Blade
Jul 18, 2020
25
28
3
Hardy, VA
I have searched the interwebs as well as at this forum and other tractor centric places for a clean answer. The signal to noise ratio is about as high as one might expect - hence my post.

I have a SQ480 rotary cutter that I bought used as a package with my first tractor back in 2020. It had an unknown history but appeared top be in decent shape. It was used sparingly but effectively for a year or two. However, it has sat for the better part of two years out in the weather. I need it now, so I dragged it over to the shop to do a total servicing on it and I discovered that there was zero oil in the gearbox. I checked it with a flexible penlight and the gears were dry with a patina of rust. I refilled it with 80w-90 and before I could get the cutter out of the shop, there was a decent pool of oil on the floor. So I know what I am facing - a blown lower main seal.

I ordered a new one and the replacement went far, far easier than some had detailed on the internet. I guess I was lucky and it all came apart without complication. So new seal went in and after buttoning it all up, I filled her up with 80w-90 and all was dry after 10-15 mins. I fired it up and spun the blades for a few mins and again... no leaks. I took it out and mowed for 15mins without any adverse sounds, vibration, etc... I stopped to check oil levels and the gearbox was cool to touch and the main seal had not leaked yet. I was congratulating myself until I loosened the side drain cap and oil forcefully exploded out the hole.

So I know I am likely facing a vent cap up top of the gearbox that is not working correctly. I plan to clean it and retry and if that is not effective, I will replace. They are quite pricey for what they are - almost $30. Anybody know what thread and pitch they are?

My concern comes from the color and quality of the oil that came out. I know water and air micro bubbles will make the oil look milky. I am virtually sure that the gearbox was mostly dry at the outset cause I got a flexible penlight way down deep inside. I am pretty sure what I am looking at is the surface rust from all the gears that I could see has now rubbed off and is in suspension in the oil.

I kinda feel like I am overthinking this but I really want to drain all this oil out, use some sort of solvent to rinse and flush out the gearbox of all the particulate matter, and then refill with clean 80w-90 gear oil. I feel like many out there would say - "screw it! keep the current oil topped off for the season, run it like you stole it, and then change at the beginning of next season." But man... my OCD is pulling me to do a flush. The problem is I have found suggestions online to use mineral spirits, kerosene, diesel, and isopropyl alcohol mixed with ATF to do the rinse.

Is there any consensus among you more experienced tractor operators as to the best way to handle my situation (leave well enough alone vs flush and refill) and if its the latter, what is the best solvent and procedure to do so.

Thanks - TP
 
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TheOldHokie

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windyridgefarm.us
I have searched the interwebs as well as at this forum and other tractor centric places for a clean answer. The signal to noise ratio is about as high as one might expect - hence my post.

I have a SQ480 rotary cutter that I bought used as a package with my first tractor back in 2020. It had an unknown history but appeared top be in decent shape. It was used sparingly but effectively for a year or two. However, it has sat for the better part of two years out in the weather. I need it now, so I dragged it over to the shop to do a total servicing on it and I discovered that there was zero oil in the gearbox. I checked it with a flexible penlight and the gears were dry with a patina of rust. I refilled it with 80w-90 and before I could get the cutter out of the shop, there was a decent pool of oil on the floor. So I know what I am facing - a blown lower main seal.

I ordered a new one and the replacement went far, far easier than some had detailed on the internet. I guess I was lucky and it all came apart without complication. So new seal went in and after buttoning it all up, I filled her up with 80w-90 and all was dry after 10-15 mins. I fired it up and spun the blades for a few mins and again... no leaks. I took it out and mowed for 15mins without any adverse sounds, vibration, etc... I stopped to check oil levels and the gearbox was cool to touch and the main seal had not leaked yet. I was congratulating myself until I loosened the side drain cap and oil forcefully exploded out the hole.

So I know I am likely facing a vent cap up top of the gearbox that is not working correctly. I plan to clean it and retry and if that is not effective, I will replace.

My concern comes from the color and quality of the oil that came out. I know water and air micro bubbles will make the oil look milky. I am virtually sure that the gearbox was mostly dry at the outset cause I got a flexible penlight way down deep inside. I am pretty sure what I am looking at is the surface rust from all the gears that I could see has now rubbed off and is in suspension in the oil.

I kinda feel like I am overthinking this but I really want to drain all this oil out, use some sort of solvent to rinse and flush out the gearbox of all the particulate matter, and then refill with clean 80w-90 gear oil. I feel like many out there would say - "screw it! keep the current oil topped off for the season, run it like you stole it, and then change at the beginning of next season." But man... my OCD is pullingll me to do a flush. The problem is I have found suggestions online to use mineral spirits, kerosene, diesel, and isopropyl alcohol mixed with ATF to do the rinse.

Is there any consensus among you more experienced tractor operators as to the best way to handle my situation (leave well enough alone vs flush and refill) and if its the latter, what is the best solvent and procedure to do so.

Thanks - TP
Yes you exhibit symptoms of OCD o_Obut drain (no solvent flush) and refill with fresh oil.

Dan
 
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85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
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Bedford - VA
I have searched the interwebs as well as at this forum and other tractor centric places for a clean answer. The signal to noise ratio is about as high as one might expect - hence my post.

I have a SQ480 rotary cutter that I bought used as a package with my first tractor back in 2020. It had an unknown history but appeared top be in decent shape. It was used sparingly but effectively for a year or two. However, it has sat for the better part of two years out in the weather. I need it now, so I dragged it over to the shop to do a total servicing on it and I discovered that there was zero oil in the gearbox. I checked it with a flexible penlight and the gears were dry with a patina of rust. I refilled it with 80w-90 and before I could get the cutter out of the shop, there was a decent pool of oil on the floor. So I know what I am facing - a blown lower main seal.

I ordered a new one and the replacement went far, far easier than some had detailed on the internet. I guess I was lucky and it all came apart without complication. So new seal went in and after buttoning it all up, I filled her up with 80w-90 and all was dry after 10-15 mins. I fired it up and spun the blades for a few mins and again... no leaks. I took it out and mowed for 15mins without any adverse sounds, vibration, etc... I stopped to check oil levels and the gearbox was cool to touch and the main seal had not leaked yet. I was congratulating myself until I loosened the side drain cap and oil forcefully exploded out the hole.

So I know I am likely facing a vent cap up top of the gearbox that is not working correctly. I plan to clean it and retry and if that is not effective, I will replace. They are quite pricey for what they are - almost $30. Anybody know what thread and pitch they are?

My concern comes from the color and quality of the oil that came out. I know water and air micro bubbles will make the oil look milky. I am virtually sure that the gearbox was mostly dry at the outset cause I got a flexible penlight way down deep inside. I am pretty sure what I am looking at is the surface rust from all the gears that I could see has now rubbed off and is in suspension in the oil.

I kinda feel like I am overthinking this but I really want to drain all this oil out, use some sort of solvent to rinse and flush out the gearbox of all the particulate matter, and then refill with clean 80w-90 gear oil. I feel like many out there would say - "screw it! keep the current oil topped off for the season, run it like you stole it, and then change at the beginning of next season." But man... my OCD is pulling me to do a flush. The problem is I have found suggestions online to use mineral spirits, kerosene, diesel, and isopropyl alcohol mixed with ATF to do the rinse.

Is there any consensus among you more experienced tractor operators as to the best way to handle my situation (leave well enough alone vs flush and refill) and if its the latter, what is the best solvent and procedure to do so.

Thanks - TP
I am with Dan - fill and replace oil until it clears up.

On the vent is it possible to fix the old vent? or can the top of the vent be fixed? Looking at drawing there is a cap - can the underside be cleaned so that it will work?
 

trikepilot

New member

Equipment
B2620HSD w/ LA364 BH65, 48in Bush Hog, Bush Hog rear blade, Woods 5ft Box Blade
Jul 18, 2020
25
28
3
Hardy, VA
I am with Dan - fill and replace oil until it clears up.

On the vent is it possible to fix the old vent? or can a "hole" be drilled to relieve the pressure without allowing water back into it?
I have seen where some report that they soak the vent cap in mineral spirits for a bit and then work the spring mechanism loose. Seems like worth a try.

Two responses and both from "Hokies." I am located in Hardy at SML.
 

mcfarmall

Well-known member

Equipment
Kubota M5660SUHD, Farmall C
Sep 11, 2013
1,389
1,661
113
Kalamazoo, MI
Fix the vent plug, then do a drain and refill if that will appease the OCD gods.

Applied OCD is the name of a popular YouTube channel.
 

rc51stierhoff

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B2650, MX6000, Ford 8N, (BX sold)
Sep 13, 2021
2,130
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Ohio
I have searched the interwebs as well as at this forum and other tractor centric places for a clean answer. The signal to noise ratio is about as high as one might expect - hence my post.

I have a SQ480 rotary cutter that I bought used as a package with my first tractor back in 2020. It had an unknown history but appeared top be in decent shape. It was used sparingly but effectively for a year or two. However, it has sat for the better part of two years out in the weather. I need it now, so I dragged it over to the shop to do a total servicing on it and I discovered that there was zero oil in the gearbox. I checked it with a flexible penlight and the gears were dry with a patina of rust. I refilled it with 80w-90 and before I could get the cutter out of the shop, there was a decent pool of oil on the floor. So I know what I am facing - a blown lower main seal.

I ordered a new one and the replacement went far, far easier than some had detailed on the internet. I guess I was lucky and it all came apart without complication. So new seal went in and after buttoning it all up, I filled her up with 80w-90 and all was dry after 10-15 mins. I fired it up and spun the blades for a few mins and again... no leaks. I took it out and mowed for 15mins without any adverse sounds, vibration, etc... I stopped to check oil levels and the gearbox was cool to touch and the main seal had not leaked yet. I was congratulating myself until I loosened the side drain cap and oil forcefully exploded out the hole.

So I know I am likely facing a vent cap up top of the gearbox that is not working correctly. I plan to clean it and retry and if that is not effective, I will replace. They are quite pricey for what they are - almost $30. Anybody know what thread and pitch they are?

My concern comes from the color and quality of the oil that came out. I know water and air micro bubbles will make the oil look milky. I am virtually sure that the gearbox was mostly dry at the outset cause I got a flexible penlight way down deep inside. I am pretty sure what I am looking at is the surface rust from all the gears that I could see has now rubbed off and is in suspension in the oil.

I kinda feel like I am overthinking this but I really want to drain all this oil out, use some sort of solvent to rinse and flush out the gearbox of all the particulate matter, and then refill with clean 80w-90 gear oil. I feel like many out there would say - "screw it! keep the current oil topped off for the season, run it like you stole it, and then change at the beginning of next season." But man... my OCD is pulling me to do a flush. The problem is I have found suggestions online to use mineral spirits, kerosene, diesel, and isopropyl alcohol mixed with ATF to do the rinse.

Is there any consensus among you more experienced tractor operators as to the best way to handle my situation (leave well enough alone vs flush and refill) and if its the latter, what is the best solvent and procedure to do so.

Thanks - TP
Good day.

I am answering just the question of the thread title…probably yes to both 😉, but that’s not necessarily wrong either…welcome to the OCD club. I don’t know what’s right but I get myself wrapped around axle with that type situation.

Crud in the oil will not help with longevity. Is it necessary to replace / clean? Hard to say / prove for an individual, but common sense says a lot…fresh/clean oil is better generally than old dirty oil with gear shavings or rust scale.

I don’t know what is what is the right thing to do, but I’m with Dan on this…rinse(fill with oil) and repeat until happy.
 

DustyRusty

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2020 BX23S, BX2822 Snowblower, Curtis Deluxe Cab,
Nov 8, 2015
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Hell, if you want to be OCD, then the only solution to the problem is to disassemble, clean, inspect, and then reassemble replacing any worn or questionable parts and then refill with your choice of lubricants. If you do this, you will never have any reason to question the gearbox ever again.
 

trikepilot

New member

Equipment
B2620HSD w/ LA364 BH65, 48in Bush Hog, Bush Hog rear blade, Woods 5ft Box Blade
Jul 18, 2020
25
28
3
Hardy, VA
Hell, if you want to be OCD, then the only solution to the problem is to disassemble, clean, inspect, and then reassemble replacing any worn or questionable parts and then refill with your choice of lubricants. If you do this, you will never have any reason to question the gearbox ever again.
Ha! This old Bush Hog Squealer is not worth that level of effort. I will focus on the vent cap for now.and then flip it over with my FEL, drain oil, and flip it back over for a refill
 

Flintknapper

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L2350DT
May 3, 2022
1,642
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Deep East Texas
You definitely need a working 'vent' whatever that takes.

Then, if it were me....I'd drain the gear lube and replace with John Deere 'Corn Head Grease' and be done with it.
 
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trikepilot

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B2620HSD w/ LA364 BH65, 48in Bush Hog, Bush Hog rear blade, Woods 5ft Box Blade
Jul 18, 2020
25
28
3
Hardy, VA
You definitely need a working 'vent' whatever that takes.

Then, if it were me....I'd drain the gear lube and replace with John Deere 'Corn Head Grease' and be done with it.
Yup. That was my plan if the stumpjumoer and plates would not come off but as it worked out all that was a breeze and I got the seal replaced easily. But corn head grease will be there as a backup plan
 

hedgerow

Active member
Jan 2, 2015
236
200
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Malcolm NE
You definitely need a working 'vent' whatever that takes.

Then, if it were me....I'd drain the gear lube and replace with John Deere 'Corn Head Grease' and be done with it.

This is what you need to do. My bat wing mower came from the factory with corn head grease in it. I don't think there is a gear box on this farm that has 80-90 in it any more and that includes the windmill gear boxes.
 

GrizBota

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I’d wonder if there’s anymore damage than you think. Being as it was run at least occasionally for a couple seasons sans gear lube if you didn’t notice it leaking. The previous owner may have done the same, or there at least there’d been gear lube visible on the gear box and deck (maybe it was cleaned prior to sale). Not sure how the sound of dry gears going around at 540 rpm wouldn’t have been painful. You say it’s quiet now, so maybe you got real lucky somehow.

I know my LP rotary cutter’s gearbox made some noticeable noise for years (and it did have gear lube and Lucas in it) before it destroyed the gear set one fine day. But I did abuse it for about 15 years, nearly used it as a shredder mulching downed limbs and manzineta bushes.
 

D2Cat

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Hell, if you want to be OCD, then the only solution to the problem is to disassemble, clean, inspect, and then reassemble replacing any worn or questionable parts and then refill with your choice of lubricants. If you do this, you will never have any reason to question the gearbox ever again.
AND...don't leave outside uncovered! At least fabricate some sort of cover you can tie over the gearbox.
 
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Soopitup

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BX23S
Oct 25, 2018
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New England
If you have rust particles suspended in the oil it should be drained and filled until the oil is clean. That's not ocd, that's common sense.:)
 
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trikepilot

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Equipment
B2620HSD w/ LA364 BH65, 48in Bush Hog, Bush Hog rear blade, Woods 5ft Box Blade
Jul 18, 2020
25
28
3
Hardy, VA
AND...don't leave outside uncovered! At least fabricate some sort of cover you can tie over the gearbox.
It is now undercover. I moved around a bunch of firewood in a shed to make some room for it. I plan to spin it up to get the lube warmer and any particles suspended and then drain and refill. I might do this a few times since gear oil is cheap. Replaced seal is holding with no leaksso I can keep the corn head grease as a backup plan .

20240331_132414.jpg
 

85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
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113
Bedford - VA
It is now undercover. I moved around a bunch of firewood in a shed to make some room for it. I plan to spin it up to get the lube warmer and any particles suspended and then drain and refill. I might do this a few times since gear oil is cheap. Replaced seal is holding with no leaksso I can keep the corn head grease as a backup plan .

View attachment 125330
Great looking helpers!
 

DustyRusty

Well-known member

Equipment
2020 BX23S, BX2822 Snowblower, Curtis Deluxe Cab,
Nov 8, 2015
5,547
4,152
113
North East CT
It is now undercover. I moved around a bunch of firewood in a shed to make some room for it. I plan to spin it up to get the lube warmer and any particles suspended and then drain and refill. I might do this a few times since gear oil is cheap. Replaced seal is holding with no leaksso I can keep the corn head grease as a backup plan .

View attachment 125330
I would get it up on a couple of pallets so the air can circulate under it so the steel doesn't rust. Even though the ground appears dry, under the mower it will be damp.
 

fried1765

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Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
Nov 14, 2019
6,998
4,422
113
Eastham, Ma
It is now undercover. I moved around a bunch of firewood in a shed to make some room for it. I plan to spin it up to get the lube warmer and any particles suspended and then drain and refill. I might do this a few times since gear oil is cheap. Replaced seal is holding with no leaksso I can keep the corn head grease as a backup plan .

View attachment 125330
Your "helpers" look great.
I have had both colors, but now have only white.
My Sadie is a sweetheart, as ALL Labs are!
 

trikepilot

New member

Equipment
B2620HSD w/ LA364 BH65, 48in Bush Hog, Bush Hog rear blade, Woods 5ft Box Blade
Jul 18, 2020
25
28
3
Hardy, VA
Thanks. Tucker and Jasper are not exactly alot of "help" but they are good pups. They are brothers from the same litter and only 9mos old.