Phantom Posted April 2, 2014 Share Posted April 2, 2014 (edited) About a year ago a new problem started to appear. Whenever I would step on the gas lightly in 6th gear at low RPM I would get a rattling sound and slight vibration out of the rear end of the car. Under heavy load (full throttle) it would go away. It didn't do it in any other gear. I got under the car and went through every nut/bolt on the drivetrain and suspension and made sure they were all tight. Also looked for "shiny spots" and saw none. Even looked at the exhaust on the off chance it was involved somehow. Didn't find anything. Now the sound/vibration is worse and occurs in 4th & 5th as well as 6th. Anyone else encountered something like this? Really don't want something to detonate on me like the u-joint I lost on a halfshaft about 5 years ago. Any suggestions? Drivetrain is LS1/T56/R200 LSD w/u-joint half shafts. This is a JCI conversion the whole way. The only difference is that the T56 tailshaft is connected directly to the R200 nose with a pair of C-channel that form something similar to a Corvette torque tube. The driveshaft runs through the center of the channels. This was done only on my car because it was considered too elaborate for a kit and not offered commercially. Edited April 2, 2014 by Phantom Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted April 2, 2014 Share Posted April 2, 2014 Any chance a piece of hardware has gotten into the spare tire well or on the floor under the seat? Stuff like that can sound horrible. Look for loose muffler mounting bolts/brackets. Quote Link to comment Share on other sites More sharing options...
Phantom Posted April 3, 2014 Author Share Posted April 3, 2014 Rebekahsz - Absolutely not. Spare tire well is padded and has nothing in it. The noise is RPM related and has a vibration associated with it. Having detonated a halfshaft u-joint in the past I'm getting pretty paranoid about this. The car got home from tri-cityies (about 90 miles)last Saturday but I was nervous the whole way. I need to get under it again and do a more serious inspection. There has to be some kind of indication of what is going on. Quote Link to comment Share on other sites More sharing options...
ktm Posted April 4, 2014 Share Posted April 4, 2014 Check the C-channel welds/connection to the R200. The R200 flexes under load and the engine & transmission twist under load. It sounds like something may be fatiguing. Quote Link to comment Share on other sites More sharing options...
Phantom Posted April 4, 2014 Author Share Posted April 4, 2014 Good suggestion. The sound/vibration I get doesn't sound like a differential issue but it needs to be eliminated as a possibility. I'm really thinking it's a half-shaft u-joint. A slow failure is difficult to detect in those things based on the last failure I had so I'm going to really dig into them over the next few weeks. It's tax time and I want to be sure I still have some money left after I pay the feds and the county property taxes. Quote Link to comment Share on other sites More sharing options...
Phantom Posted April 30, 2014 Author Share Posted April 30, 2014 Turns out it was the bolts holding the R200 to the mustache bar. Both were loose enough that the lock washers would turn by hand. Tightened them up and the noise is gone. Quote Link to comment Share on other sites More sharing options...
Savage42 Posted May 1, 2014 Share Posted May 1, 2014 (edited) Gotta love when it's that simple and easy to fix! Right on! Edited May 9, 2014 by Savage42 Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 4, 2014 Author Share Posted May 4, 2014 I was headed out of my driveway yesterday when I rolled across a rough spot that I normally avoid because I'd get a "thump" that sounded like one of the rear struts wasn't bolted down tightly on the top. I had checked them a few times and both were tight so it had me perplexed. Yesterday there was no "thump". Now I have another audible tell-tale of loose differential mounting bolts. Two worrisome noises with one cure. Now I only have one loose nut in the car rather than three. Quote Link to comment Share on other sites More sharing options...
ktm Posted May 11, 2014 Share Posted May 11, 2014 Thank you for coming back and posting the solution. Many times people are left wondering what was the ultimate cause. Cheers. Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 12, 2014 Author Share Posted May 12, 2014 Thank you for coming back and posting the solution. Many times people are left wondering what was the ultimate cause. Cheers. I know exactly what you mean. I'm still thinking about going in and backing up the nut and lock washer set-up with a nylon insert locknut. I don't ever want this to happen again. It really messes with my Z quality time. This time it caused me to miss a Maryhill Loop hill climb near Goldendale, WA. Bummer Quote Link to comment Share on other sites More sharing options...
Slow78z Posted May 20, 2014 Share Posted May 20, 2014 Take a look at Nord-lock lock washers. We use those at my work (industrial) and they never loosen. They are a bit expensive but very reliable. I also use them on header bolts and have never had any issues with them. http://www.nord-lock.com/nord-lock/wedge-locking/washers/introduction/ Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 22, 2014 Author Share Posted May 22, 2014 Take a look at Nord-lock lock washers. We use those at my work (industrial) and they never loosen. They are a bit expensive but very reliable. I also use them on header bolts and have never had any issues with them. http://www.nord-lock.com/nord-lock/wedge-locking/washers/introduction/ Thanks for the suggestion. I figured I'd jet back up the existing stuff with some nylocks. This is a good alternative. Quote Link to comment Share on other sites More sharing options...
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