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Superior Fan Gearbox Service
My 94′ coach has an 8V92 engine and the cooling system is equipped a “Superior” brand fan gearbox. Sorry, I don’t have a model number – all I can read is the Superior name. The gearbox is preplexing in that there is no dip stick to manage fluid levels nor can I find any provisions for draining the oil short of taking the unit down. The unit does have what appears to be a ceramic tube projecting from the top of the box. On top of the tube is a nut and o-ring, which once removed, allows access into the box. I have used small gage wires to check the fluid level but the wire always comes out dry. Of late, I am noticing a change in the frequency of the sound coming from either the fan or the gearbox. I suspect the change is coming from the gearbox and I would like very much to drain and replenish the oil before things worsen. Anyone dealt with a similar situation and if so how did you drain the unit? Thanks for your help!
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25 Replies
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Mine has a dip stick for checking the level. My chassis is a 2006 model year, and a 60 series, just so you know. I also have a vent line that goes up also from on top of the unit. If you can’t find oil when putting a wire in, I would be concerned. There has to be some way to check it and change it. On mine Prevost TN simply put a small hose in the dip stick hole and used a pump to suck it dry and then replaced with new oil.
When you put the wire in, is it going all the way to the bottom, or do you hit obstructions preventing you reaching the bottom? Also, do you notice any leaking around the pulley shafts at all? It sounds like you have a dry box. If so, I would be very concerned that the drive may already be damaged.
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Tom,
You have to use a dip stick to check the oil level, I used to use a small wooden dowl on your bus and the level never changed. I would think there would be a drain plug somewhere on the bottom, but if not, it can be sucked out like Mark suggested. The series 60 I now have has two plugs, one a level plug, the other a drain plug. I fill it from the top which is a vent.
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If I am picturing it right there is an allen set screw at or near the center of the gearbox that is used for setting the level. I think the level is set by adding oil until it runs from the hole. Having said that my 97 had an allen screw I could not remove so I unscrewed the top fitting and used a screw driver to check the level and compare it to the distance down to the allen screw.
The current bus has a dip stick. That makes 5 dipsticks. Oil, Transmission fluid, power steering fluid, gear box, and the driver.
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On mine there is a 1/4″ hex drain plug on the left side bottom
On the right side the fill & oil level plug.
On the top is the Mfg data.
Buy at Walmart or wherever a catsup/mustard dispenser set for filling.
1/4″ hex wrench to remove plug. An extension of the wrench might be required if the plug is too tight (may be locktite sealed). Caution: be mentally prepared to deal with the possibility of stripped threads if you use too much force on a stubborn plug!
One can of special oil (best source Prevost) due to the small amount required.
I cut a plastic water bottle to have a flap to slide under the gear box to direct the draining oil into it. Use your imagination here. Some place cardboard on the ground or rags or kitty litter or or or. With my way I changed the oil in a public parking lot and did not spill a drop. I believe it is better to drain than pump the old oil as this ensures the crap if any in the bottom comes out.
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Many thanks to all of you for your input and Jon I too join the ranks of a dipstick, at least my grandkids think so!
I am not sure that my unit has a level plug or a drain plug as you suggest. I will clean the unit up and see if I can retrieve the data and perform a closer examination to determine if there are plugs that I have missed. I wonder if there might be a drain plug on the bottom but it is inaccessible because of the support bracket. My bracket is similar to that shown in Jim’s photos. Tom, good idea to use a dowel as a dipstick. I have perused Superior’s web site but can not find a gear box there that looks exactly like mine. It was disappointing that their website has no provisions for tech support or info on manuals.
Best regards to you all.
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You may be right Tom, maybe it’s hidden by the mounting bracket. Are you seeing signs of oil leakage or just concerned that it’s low?
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Tom, yes there are signs of a leak but not bad.
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Post a picture and we will tell you what we see and how we interpret it.
Wondering do you have the vent hole in the top? If you have that vent, work through it by sucking out the old oil and filling through it.
I doubt that the manufacturer would make a product that could not be maintained.
Oh yes, be sure the gearbox is spotlessly clean before opening it ( the plugs that is) if you allow dirt to enter that will be worse than leaving the whole thing untouched.
Something comes to mind here that is not pointed to you, just that I am stating it here because I thought of it; many times additional problems are created by untrained, ill informed, do it yourselfers trying to repair/maintain their “things” themselves. This can often lead to disappointment and extra expense. Of course this will also lead to wisdom, experience and knowledge.
JIM adding a smile, because they are not provided
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Tom, I have been trying to find a photo of my modifaction to my gear box like yours.
First of all you have to slant the stick to get it to the bottom of the box, should be half full of oil.
To change the oil, you have to loosen the four mounting bolts and lift the box up to access the drain bolt. After I drained mine, I put a 90 degree brass elbow in and a 3 inch pipe and plug to drain in the future.
If I locate my photo, I’ll post it. Or if you want I can just walk out and take another one.
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Jim,
I understand where you are coming from with regards to being properly trained and knowledgeable but I have been screwed so many times by folks who suposedly meet this criteria that I have “thrown in the towel”. I take the attitude now that if I do my home work, keep it safe, manage to have the proper tools, use approved materials, parts and procedures, and be deliberate in my actions, I can do as good of a job as most folks. At least in the end I know what results were achieved. This post is part of my homework.
I will also try to post some photos in the next few days. My bus is in storage away from home and the weather is nasty at present.
Thanks for your input.
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Dale,
I found the picture you are referring to on the other forum. I believe you have come up with a good solution. I am curious though if you had problems aligning things up when you put the gearbox back in place? I assume yours is the same as mine and it must have been a bear to take the box out.
Thanks for your help.
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Any time a belt driven device is removed and replaced a great degree of care is necessary to assure proper alignment. The gearbox is a device that requires even greater care because it is driven and driving in two planes.
I am not a mechanic. Understand that when reading the following.
If I were to remove my gearbox to service it, my first step in the process would be to create alignment marks after I carefully inspected the gear box belts to satisfy myself the original position is/was correct and that there is no indication of uneven belt wear. Since I have never seen any indication of belt wear that would typify misalignment I would take a scribe and create enough marks to assure I could duplicate its original position. I would scratch an outline in the base it is mounted on, or put marks on the gearbox and base or in some fashion insure I could duplicate where it sits.
I would also not touch or relocate a pulley on the shaft. Other than those precautions I suspect gear box removal and replacement would be fairly easy.
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I did not remove my gear box, I just removed the four mounting bolts and raised the box to get to the drain plug. From that point, I could modify the drain and lower the box back into place and then install the four mounting bolts.
When I had first looked things over, I thought, If I remove the gear box completly, then I would bore a 1 inch hole in the middle of the mounting plate to access the drain. I not sure why Prevost didn’t frabricate it that way.
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In defense of Prevost and converters I would like to address Dale’s comment about adding a hole for gear box service.
Like Dale I have been “hands on” when it comes to working on my coaches. I have had three now, each being about 10 years newer than the previous one. When working on each coach I have grumbled about such things as lack of access, difficulty doing routine things, and a failure to make things easy when to do so would involve little effort. So I would modify my coach when practical to make life easier. The best example I can give is the incredibly difficult location for the air fitting on the top of the front air bags. I ended up modifying a tool to access and loosen or tighten the fitting. Finally on the King’s coach when Roger and I were changing air bags we added a 4 1/2″ copper nipple to move the fitting to a more accessible location saving considerable time removing and replacing front air bags.
Now I find that is how they are produced. There are many other examples of how each succeeding coach I have had has changes and improvements to make service and access easier.
The problem is once a design is released for production and the coach and conversion reaches the market, these needs which are obvious when the coach is being serviced may not be so obvious to the engineers or manufacturing people. But Prevost and the converters also service our coaches and they have the same problems we do so they offer the feedback which results in improvements.
The bottom line however is that our coaches are a dream to work on compared to the average car.
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