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"Host" of Barthmobile.com 1/19 |
(loud drum noise: BUMM,BUMM,BUMMM) Maybe I was wrong. (I've looked, the world did not come to an end) There is more that I can tell you. You'll have to get dirty if you want to do this. I don't suspect you will do it, but to cover all the bases... If you want to check the brake drum for balance and/or just the G/V then remove the U-joint at the transmission and put the vehicle in drive. Step on the throttle slowly until speedometer reads the max speed you would ever travel in a Barth. Take it easy as there is no real resistance so it will get up to speed very quickly. Try out your G/V in different speeds and note what it's doing. Common sense says you've got to be carefull. Also this same principle applies to how your going to use the G/V while doing this. If you don't know what I mean by this then don't attempt it! Because your parking brake is attached to the back of the transmission there will be no parking brake. Make sure your on a flat surface when doing any part of this and that ALL OF YOUR WHEELS ARE CHOCKED FRONT AND REAR. I know this sounds like overkill (it is) but I would hate to get a knock on my door with a "notice to appear" because the two wheel chocks on one wheel came out and it rolled away on you. After you have done your testing to see if the drum and or G/V is causing your problem place transmission in NEUTRAL, wait till the speedo stops or slows down to just about nothing and then turn off the vehicle. DO NOT place it in park until the engine has been turned off for several seconds and the speedo is NOT MOVING as you'll destroy the parking pawl inside of the transmission. The driveshaft is measured from the center of U-joint to center of U-joint. You are measuring "unsupported length"? You need to measure "the Driveshaft" from "yoke to yoke". If you want to see if the long driveshaft is out of balance then do this same thing by taking the U-joint apart after the carrier bearing and then test again. Hope this extra stuff helps you out.
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2/16 Captain Doom |
I'd not recommend that procedure, because if the shaft is out-of-true or out-of-balance, it can start to whipsaw, and there's no quick way to slow it down... Rusty "StaRV II" '94 28' Breakaway: MilSpec AMG 6.5L TD 230HP Nelson and Chester, not-spoiled Golden Retrievers Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering. - Arthur C. Clarke It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields | |||
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"Host" of Barthmobile.com 1/19 |
Wouldn't it "whipsaw" with the U-joint and rest of the driveshaft hooked up too? The only difference is he's not doing this on the road under a load condition turning the rear end. He's just checking to see if the driveshaft or G/V is what's out of balance or making the harmonic noise etc... The carrier bearing would hold up the driveshaft just the same. The driveshaft will still turn at the same RPM. The only difference would be if the coach is moving or staying still. There would be no load factor to cause a gear noise problem. Just trying to see if the driveshaft is a contributing factor. I could have also told him to take the axle's out (cap off axle ends) and try that too. I just figured the only thing that's changed was the G/V and the first driveshaft. Trying to find what's causing this by taking things out and adding them back into the picture etc...
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2/16 Captain Doom |
I misunderstood which U-joint you suggested unhooking - I thought you meant the foremost one, at the drive end of the GV box... In any event, if the drive shaft is to be tested by disconnecting any other U-joint, I suggest it be a two-person operation, where there's an observer to watch the driveshaft for erratic behavior. Depending where the intermediate bearing is, there may be little chance of whipsaw. It's my totally-off-base opinion that the GV whine is normal (if not appreciated), because I think that an out-of-true/balance driveshaft would have been previously noticed. Unless the installer used a torch to cut the shaft, or cut of a counterweight, the driveshaft should be OK. But then I don't worry about that, because the driveshaft on the Breakaway is about 12". Rusty "StaRV II" '94 28' Breakaway: MilSpec AMG 6.5L TD 230HP Nelson and Chester, not-spoiled Golden Retrievers Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering. - Arthur C. Clarke It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields | |||
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The Old Man and No Barth |
Humbojb -You've gone from a new small noise when you installed the G/V 2 1/2 months ago, to a time bomb of potential disaster, on the basis of disastrous mental images conjured by a bunch of real and/or presumtive mechanics who haven't put their hands on the machine, & have looked at only your verbal description. Point #1 - If everything from the engine to the handbrake drum is bolted together, you don't have 82" of unsupported weight. You have a rigid length of machinery supported by the engine & tranny mounts, plus a 60" drive shaft, half of whose weight is supported by the intermediate support bearing. Point #2 - Your 60" long front drive shaft runs with little angularity because it's bolted to the back of the engine/tranny/G/V combination in nearly a straight line to the first support bearing after the machinery. It has U-joints to compensate for less-than-perfect alignment, & chassis flexing. If the shaft is made of adequate material it isn't going to twist or whip. IMHO you're better off with the G/V & one 60" drive shaft in this circumstance, than you were with 2 short drive shafts & another pillow-block bearing to bridge the same distance. When you lost the extra drive shaft, you also lost several mechanical components that wear out & break down. If all you have is the new whine, & there's no severe vibration, no evidence of worn U-joints, etc.. I'd say enjoy your new-found economy, quiet, & hill-climbing efficiency. Cars have been my toys for 62 years. It took me at least 30 years to learn this lesson: IF IT AIN'T BROKE, DON'T FIX IT!!! | |||
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"Host" of Barthmobile.com 1/19 |
This sounds like your driveshaft is 66 inches long. Doesn't sound too long now. I have reread this post many times and this is sounding more and more like what Ed is describing. You could tell if it is the Gear Vendor by performing these checks. Now if you wanted to check out the driveshaft reinstall at this time only up to the first carrier bearing and remove that U-joint. This will allow you to check the whole set up with the new driveshaft attached. You probably have nothing wrong with the driveshaft or G/V. Have you been called a nit-pick? I'm not trying to torque you off here but how bad is this really? I would think with the lower engine noise you would now hear other noises. I would love to get my hands on this for a test drive but know this is not going to happen. I would do the testing myself as described above and then also disconnect the trans mount and install a piece of support under it to isolate the weight noise transfer of the cross frame support. There are a lot more testing that a real repair shop could do and as stated earlier...You need professional help that no amount of typing is going to give you. You really need someone who you trust to give you the facts only after looking at it. This isn't something someones going to fix for you over the phone or by responding to an email. There's a warranty with the G/V so have them look at it again. See what they recommend. Have an independent repair shop give you a diagnosis based upon lookin at it and go from there. Good luck to you. Let us know what was or wasn't found as I'm very interested in the eventual outcome.
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