Gearbox repair for FMC sidewinder

MGnoob

New member

Equipment
L175
Aug 27, 2025
12
1
3
Massachusetts, USA
I’m looking for Parts to rebuild what I believe to be an FMC sidewinder.. i’ll attach some photos. I wish I took better ones when I had it apart.

what I found interesting is the horizontal shaft is just a shaft with a gear on it. It doesn’t look like the other ones I’ve seen on YouTube for rebuilds that has a shaft that goes all the way to the other side of the housing and goes in a bearing.

I got it for free and I didn’t make it very far before it failed. I didn’t hit anything. I put oil in it before I started. It appeared to have some grease in it but when I drained it, there wasn’t. My guess would be as they stopped using this tractor because their plow head broke and this brush hog was pretty much dead..
it raddled horribly on start up.. but then it’s moved out and I did start and stop a few times. Everything seemed fine.

I didn’t hit anything

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i’m looking to get Parts the thing seems way too big for my L175 but they had been running on it and it seemed to work great I wish I could post a video. The other side of the deck looks brand new. There’s only a couple dents in the exterior of the deck and while you can’t be free. … I’d like to get it fixed.
 

Fedup

Active member
Apr 6, 2016
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Winchester
I would say it's salvageable, but the gear teeth are a long way from "new condition". You can clean and dry the gears, then using a hand grinder knock the high spots off the edges of the teeth and they will probably survive a few more acres. Take the hog nose apart and see what the hidden parts of the shaft and the outer bearing race bores look like. Then try shaking the blade holder (stump jumper if it has one) and see how tight the bottom shaft is. If that's all sloppy loose too, then it's decision time and the hard part begins. If that feels solid enough you may be able to run it as is, just using a heavy grease/gear oil mix. At that point you're only into it the cost of bearings and seals, which will be standard, off the shelf, bearing house items.
 
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MGnoob

New member

Equipment
L175
Aug 27, 2025
12
1
3
Massachusetts, USA
I would say it's salvageable, but the gear teeth are a long way from "new condition". You can clean and dry the gears, then using a hand grinder knock the high spots off the edges of the teeth and they will probably survive a few more acres. Take the hog nose apart and see what the hidden parts of the shaft and the outer bearing race bores look like. Then try shaking the blade holder (stump jumper if it has one) and see how tight the bottom shaft is. If that's all sloppy loose too, then it's decision time and the hard part begins. If that feels solid enough you may be able to run it as is, just using a heavy grease/gear oil mix. At that point you're only into it the cost of bearings and seals, which will be standard, off the shelf, bearing house items.
I like that answer. Is there any way to shim the horizontal shaft further into the vertical shaft to gain more engagement? I’ve never worked on these. I’m not completely inexperienced with gears and hack jobs.
 

MGnoob

New member

Equipment
L175
Aug 27, 2025
12
1
3
Massachusetts, USA
The current shaft on the gearbox has a 7/16 shear pin. Can I just buy this and drill out the 7/16 hole on my driveshaft to half inch? I’m worried about damaging my tractor.

I have another stupid question when I I picked up the tractor it still had the shaft on the PTO with no implement which I thought was really stupid. I freed up the pin you press but how do you pull it off the PTO shaft?
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Fedup

Active member
Apr 6, 2016
320
120
43
Winchester
Can you replace the entire gearbox? Probably, but you still have get the existing gearbox off. Will the shafts be the same (other than the shear bolt size) on both ends of the two gearboxes? Will the frame mounting bolt size and pattern match between the gearboxes? Until you take this one all apart you won't know any of that for sure.

I'm not sure why you're suddenly concerned about damaging the tractor.
 

NCL4701

Well-known member

Equipment
L4701, T2290, WC68, grapple, BB1572, Farmi W50R, Howes 500, 16kW IMD gen, WG24
Apr 27, 2020
3,112
5,041
113
Central Piedmont, NC
I have another stupid question when I I picked up the tractor it still had the shaft on the PTO with no implement which I thought was really stupid. I freed up the pin you press but how do you pull it off the PTO shaft?
If it’s stuck, it’s likely because a PTO shaft with no grease on the spline was put on the tractor PTO which was also ungreased. Leave it outside for a while to add some moisture and it’s stuck.

Assuming that’s what you’re dealing with, do NOT beat on it. Hitting it is a great way to bust expensive stuff in the rear end of the tractor. Take the U joint apart so the implement side of the shaft is removed and you’re left with just half the U joint stuck on the tractor. Gear puller and penetrating oil (Kroil, etc. not WD-40).
 
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MGnoob

New member

Equipment
L175
Aug 27, 2025
12
1
3
Massachusetts, USA
Both useful suggestions. I did get it off.
I will be disassembling that brush hog and addressing the gear box. Likely with a replacement and rebuild the other one and put it on the shelf for later.

I picked up another free brush hog..it didn’t turn but everything looked promising.. I inspected everything and then got it freed up. It’s pretty much ready to go with the exception of now the driveline for that one I can’t get long enough it’s seized. I greased it up real good and sprayed it down and applied some heat try a few methods. It’s stuck pretty good. i’m gonna let it marinate for a little bit and try again if that doesn’t work I’m gonna locate an unmovable object pull on it with my 13,000 pound backhoe. i’m gonna have to remove it from the brush hog to do that. I hope it’s not stuck there too.

other than that, the gears and bearings in it looked great. I just need to locate a top gasket or some RTV to seal it back up after I change the oil and try to find some kind of replacement dipstick..: after that I have to loosen the clutch on this one until it slips and then re-tighten I guess.

It does have two cracks in the mounting holes for the gearbox, but it’s extremely thick I’ll weld it at some point before I do a mass painting of rusty stuff.
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