[jsmith24]

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Okay guys, I know how weird this is going to sound, but I need to know how to clean out the old oil from my final drive (83 GL1100). I pulled the rear tire to have it replaced and decided to change the final drive oil while the saddlebags were off. I went to drain it and nothing came out. I just figured that it was run really low (the silver exterior was at least a 1/4 inch thick in oil and goo). I pulled the breather cap and the filler cap, nothing came out of the drain. So I just started putting in fresh hypoid. Well, the oil just came right back out the filler hole.

I poked a plastic rod into the drain hole, and for about 30 minutes or so I literally pulled the old oil out. It was about ten times thicker than any syrup I've ever seen! So, I filled it back the best I could, but I just know there's a lot of old oil in there.

What can I use to flush it?

Jack

 

[welsh winger]

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Hi jsmith24,

I have seen this problem before, people will tell you to use different kinds of slovents, not sure on this as it could affect the seals, so in the past I have filled up with new oil and spun the wheel for a while, then let it drain and repeat the process, this I know is not a quick fix, but it`s better safe than sound in my book

welsh winger

 

[jsmith24]

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Thanks, Welsh Winger.

That was my first thought, too. I got most of the sludge out, but still got only about 7 ounces (at best) of new oil in. I thought I'd run the bike for a few days or a week, drain it again while hot, then do it again and again until only the new stuff came out.

I wasn't crazy about the time factor, but at the same time I didn't feel right using brake cleaner, transmission fluid or anything else. Although, transmission fluid might not be a bad idea...but the hypoid stuff will work just fine. Besides, it's notso expensive that I can't afford an extra bottle.

Thanks for the input, and I'll still take other advice.

Jack

 

[Renegade]

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You've got the right idea Jsmith24. Repeat the procedure of riding and draining while hot and eventually the lube will run free and clean.. I've never seen gear lube as bad as you have described, but definitely seen engine oil that bad. It drained out of the crankcase so black and thick, I thought someone had put tar in the engine. Repeated runnings and flushings did the trick. Good luck...

 

[exavid]

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I would add an ounce of MMO, shouldn't hurt the seals since it doesn't in the engine, and it might help break up the old crud. Add the stuff and change oil in the final a couple times with 100miles or so interval and it should come clean. If it is still cruddy after that you'd probably have to disassemble and to a proper clean up.

:waving:

 

[JOHNO]

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Have you thought of using an engine oil flush addative?

I,ve only ever owned shaft drive bikes and had to do this a couple of times in the past.drain out as much drive oilas you can, add the the engine flush take the bike for a short ride, only enough to warm the oil mind, the sludge should break up and be easier to drain out.

If the problem is as bad as it sounds you might have to carry this out a couple of times, alternate between gear oil and flush. As the flush agent is designed for engines it should maintain lubrication to seals and bearings.

johno

 

[Dave Campbell]

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Flush with petroleum solvent containg Toluene, Acetone or xylene considering how slugg-y it is. "Paint thinner" is its street name. Run the gears around to clean the teeth and bearings. Dont leave it in for more than a few minutes so the seals dont soften - they will slightly but will firm up when the solvent leaves. Toluene will slightly soften Buna seals. Then fill with motor oil to catch the solvent, drain and install gear oil. Thats really bad if it was that much sludge. I did this to my first 1200 at about 25000 miles and the solvent came out black - this isnt unusual, but its not good either. May even have to remove the FINAL DRIVE (there - I got it right!!) and shake it around to distribute the solvent.

 

[Goldwinger1984]

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jsmith24, it's always best to drain oil when the oil is hot after a long ride. You could use a heat gun (don't melt any plastic or rubber parts)to warm up the molasses in your rear drive and then use new 80/90 hypoid oil to flush out the gears while driving. Change the oil a couple of times this season.

Vic

 

[RedWinger]

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[philcsand]

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sounds like another use for Seafoam.