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PatRarick

Noisy BVB's

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PatRarick
I have done three Vanguard conversions on 900 series AC's this past spring. All three have resulted in complaints from the owners, (myself included) that they now hear noise coming from the bvb. It is not a whine, but more of a rattling or knocking noise. The noise is identical on all three machines. None of us heard it before, we assume, due to the noisier single cylinder Kohler. On all three machines, there is no sign of bearing play, gear slop, leaks, or any other bvb, PTO clutch, or pulley problems. Since the older tractors I have converted do not make any noise, I assume the noise on the newer tractors is due to the lighter lubricant (hydraulic oil vs. 80-90) in the bvb of the newer tractors. I am going to drop the oil in the bvb of my converted 914, and replace it with 80-90 to see if this quiets the gearbox. Has anyone experienced this noise problem? Does anyone see a problem with changing to the heavier lubricant? Pat

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Dutch
Pat, In my limited experience, if the BGB bearings are good and the backlash is not excessive, “rattling or knocking” noises that seem to be coming from the BGB have actually been due to a problem in the cone clutch. Is your noise still present with the cone clutch removed? Have you tried to locate the noise source with a stethoscope? If the noise appears after an engine conversion, I would focus on driveshaft alignment, preload, or flex joints. I had one tractor where some of the flex plate washers had been installed backwards and produced a “popping” sound on every revolution. Some of Simplicity’s lubricant specifications conflict. I use 80-90 weight gear lube in all my BGBs.

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BillC
When my Sovereign was new (2 years ago) the bevel gear box had a whine. When I noticed Simplicity eliminated the drain plug from the rear cover (cost reduction idea?), I decided to put one in myself along with a magnetic drain plug. When I refilled the gear box with Mobil 1 synthetic 75W-90 gear lube the whine reduced dramatically.

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PatRarick
Dutch, The engine had to be raised 7/8" to bring the crankshaft to the correct height. When I make my adapters, I have a jig that I mount the engine to and check my height and runout with a dial indicator. It is always within .020 of the original engine. The driveshafts have not been touched on the BVB end except to loosen the setscrew on the yolk to allow for any small difference in the fore and aft position of the new engine. The noise is still there with the PTO clutch and the transmission drive belt removed. With a stethescope, it sounds like the noise is inside the gearbox itself. I just checked a 912 with the original engine. With a stethescope, I hear the same noise in the gearbox. I hear it, but just barely, on my 716 which has the heavier gear lube. It seems as if the noise is more noticeable with the quieter engine. It also only appears low idle or when quickly accelerating. It's quits when running at speeds from a high idle to full throttle, or under load. Bill, Since you and Dutch both run gear lube in your newer tractors, I feel confident in changing my gearbox lube to gear lube. Will know later tonight if that is the problem. I have a feeling that this will reduce or eliminate the noise, since I have had no problems in the conversions on the B series or the 700 series. Pat P.S. Changed to 80-90. Problem solved. Thanks, guys.

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