Hello!
I am hoping that Snowmann can give me some advice. I recently purchased a brand new 11528 Snow Thro from a local dealer to replace my 23 year old ST724 (which STILL runs!). I have used the machine twice now and I am seeing gear case oil leak from the main shaft seal on the rear of the auger gear case. The funny thing is that the first time I used it nothing leaked and the second time it leaked AFTER I parked it for a day. So, when I noticed the leak, I used a rag and completely cleaned off the gear case so that I could see where the oil was coming from. Nothing leaked out for several days, but I noticed a puddle under the machine again today, and I checked it out with a mirror and discovered that the oil had come out of the main shaft seal. I checked the oil level and it was within range, but below the Full level.
I haven't run the machine for a couple weeks now, so I am wondering how the fluid is getting up there to leak out. And I am wondering if this is a common problem?? Can I use a thicker oil (like synthetic 80-90W)? Do the PRO units have the same sealing technique? If the PRO units seal better, then I will definitely trade.
The part that disspoints me about this is I bought a new machine so I wouldn't have problems like I did with my old one every winter. If I take this in for service, my fear is that I will have a new machine that has been rebuilt - not much better than what I already had.
Any advice you could forward would be appreciated!
Bryan
95% of reported (Ariens) oil leaks are from the filler plug or the rear oil seal, and both are typically more from having too high an oil level than anything else. Hydrostatic pressure on either isn't preferable from an application standpoint.
The original intent with the higher oil level is to eliminate dry starts by placing the oil level at the gear pitch line. Given the duty cycle of a snowblower gear box, this is not really necessary. The cooling effects of the larger sump capacity are also not really needed as the large worm gear design is very low-stress and cool running (aluminum castings also wick off the heat well, much better than cast iron). The fill used to be 8 ounces (right at the bottom of the filler plug hole). With the metering equipment being used this could sometimes get to 9. This has since been dropped to 6 ounces to keep some of these leaks from happening. If you put 4-5 inch blocks under the wheels (to tip the unit forward), drain the oil down to the filler screw hole level, and clean and reinstall the filler screw. This will put you at 6 ounces and should eliminate any rear seal penetration.
The alternative is to bring it to the dealer to try to shore up the rear seal. This may be counterproductive as there could be further issues due to thermal expansion (pressure differentials). While it has not created any problems that I've heard of, it is better in practice to equalize the pressure (a vent would do this) to keep from potetnially belching oil through the seals (6 psi or greater would need to occur). The rear oil seal is very hard to seal due to concentricity imperfections with the vertical parting line running through the seal bore. This would be true of all worm gearboxes with a parting line through the rear seal bore. Toro uses a square cut O-ring which seals far worse than an oil seal. They claim this is their “vent”. As their oil level is much lower, they have no problems.
The filler plug requires cleaning and resealing with each install. Same with the filler plug hole (the cleaning part anyway). Sometimes the screws start coming from the supplier a little stingy on the pre-applied Dri-loc sealant. This occasionally can cause a slow leaker out fo the box. As every gear case is pressure tested at ~5psi through the filler screw hole this cannot currently be caught at assembly with the current process.
The other 5% of the leakers are from cut lips on the rake shaft seals. This occurs when seal installation tools develop a burr and the lips are cut upon assembly. Although this is relatively rare, new seal installation tools are currently in process to keep this from happening.
I hope this helps.
PK
