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lboy1971

front pto vs center pto?

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lboy1971
I did a search on this topic but didn't find what I was looking for in the first page of listings. So I'll ask it here. With the problems that Kent and many of us have had with the bevel gear box would it be better to use a front pto snowblower hitch than using the one that runs off the mower center pto? I have a 7117H with a center pto driven snowblower. All of my other tractors use the front pto. Would using the front pto take alot of the wear and tear off the bevel box?

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Les
Less wear & tear would certainly lengthen the life of a bevel box, but Simplicity bevel boxes are extremely durable. In my humble opinion, it is vibration and "shock load," primarily from tillers, that wreck bevel boxes. Drawing from my CAT experience, the weakest part of the dozer is the final drive, strange as it may seem today, crawler tractors were designed to pull plows, NOT push dozer blades. The shock loads transmitted back from the blade all having to be absorbed by the final drive, CAT partially remedied the problem by using under-powered engines. International and Allis dozers were crap mostly due to torn up final drives caused by high powered engines. The reason CAT went to the "high drive" was because it was cheaper and easier to go with a planetary final drive compared to the old rack and pinion, using THREE gears to absorb the shock instead of one. Also the high drive did not get the full impact of the dozer shock load due to it's high position, Therefore it is my belief that "shock load" should be your biggest concern for the safety of your bevel box and the drive position shouldn't make that much difference. Now before you say anything DUTCH! This is just my opinion, it may be right, it may be wrong. I am just trying to help. Plus I happen to know Lloyd and I am certain that he is smart enough to reason things out for himself.

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gretsch
I have not found out from first hand experience, but it used to be well known knowledge that if you used a tiller (Belt driven from the rear pto) then the bevel gear box would not last. Seems to be a rash of bad BGB's lately and I have myself been wondering how many used tillers at one time or another. It's like with an auto. If you jump the clutch hard or do jack-rabbit starts, you are taking a chance on taking out the differential which under normal circumstances should last the lifetime of an auto with no trouble. BGB / differential: basically same function and characteristics.

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Kent
I've heard the same stories of tilling stressing the BGB. I just put the used BGB in my tractor last winter, along with the hydro tranny. I pushed snow with it about 3 times, and used the mower deck. This was my first use of my vac, when it went out... I till with the Big Ten and it's Hi/Low.... The foot-draggin' Clubhouse Custodian...

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Les
There are a lot of 40+ year old B-1's and 725's out there with the original bevel boxes. I have owned over a dozen AC/Simplicities and had one bad bevel box, in a 7016 that came with a heavily used tiller and a front PTO & heavily used blower, so the front PTO didnt save that bevel box. I would believe that a lot of front blade pushing would be hard on a box too. Also, I never liked to run my differential too tight, to minimize the strain on the tractor.

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Al
Hi, Just a thought. How many other brand tractors 20 to 40 years old are now part of someones steel roof, pork and bean cans etc.? How many of you have had multiple bevel gear failures? Even a lot of the 7100s are 15 to 20 years old. When you look at the age, is this high failure rate, or just normal wear and tear. There are a lot of rebuilt automotive transmissions sold too. I have had them fail, but I beat the h___ out of them and after fixing them continued to. I have seen them with a lot of hours on them and still going. And some otherwise. One of the weaknesses [word ?] is the front bearing. When the front shaft gets play up and down, the angle on the gear teeth changes, and with shock, a hammering like action occurs. I would suspect that watching the front shaft for play might be more of a warning than anything. Also when the front bearing/shaft get loose, the lube starts to leave and the box runs with low lube. I admit I was more of a hard user, make it happen whatever it takes, but personally I wouldn't baby it. I have seen more grief with the belt set up on the front clutch, than what I would consider related BGB problems. I was thrilled to see the later drive come out. Back in 66 when I got my first Landlord, I made a snowblower drive to put a Broadmore blower on it. I made the drive similar to the new Sovereign drive. Ran the blower about 50% faster than OEM speed. When the snow was wet enough to throw well, I could Paste it about 15 feet up in the trees in the parking accross a 33 ft street. My friends front drive [normal speed] couldn't come half way to it. Nuff rambling, My thoughts and they are free. Value accordingly. Al Eden

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Woodydel
To minimize shock loads I would make a design change at the tiller. Instead of a plain drive pulley I would replace it with a combination pulley/flywheel. The flywheel I'm guessing at 25 lbs would have enough stored energy to dampen the shock loads imposed by the tiller. The BGB would then be used to simply maintain rotation of the flywheel and not be subjected to as much shock. An idler pulley with a weak spring load would also allow the belt to slip under shock loads. Simplicity mentions in their literature that a slipping belt is a strong point in their design. Loosen the belt and your shock loads will lessen.

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Les
So what is the answer? Does the higher horsepower of the newer tractors cause more bevel box failures? Or is it how hard the tractor is used? Will a front PTO help save your bevel box? Does a tiller really contribute to the box failures? Have B-1's and 725's in tiller use had a lot of failures? I remember back in the early 70's when farm tractors started going above 100 hp and they went to 1000 rpm PTO's over the old standard 540 rpm. As I recall the stated reason was that the 1000 rpm would better absorb shock loads from the higher hp engines.

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UCD
The bgb in my 7790 18 1/2 hp diesel is 17 years old and is still going strong and is tight. (knock on wood) It has been used real hard as I am not easy on it. As four worn out and smashed up snowblowers would show. From ramming into snow banks hitting sidewalk curbs plugging with stones, extension cords, street water shutoff covers. When the blower plugs and stops the auger and stalls the diesel that is a shock load. I have broken at least four sets of drive shaft disks and bent as many drive shafts. That is another real shock on it. So I don't think it is just the shock loads or the higher hp that are causing the problems. Anything free is worth what you pay for it This & $1.00 might get you a small Coffee Maynard aka/UCD

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