RacerJJ Posted April 27, 2009 Report Share Posted April 27, 2009 Ok, I've done extensive searches and I don't think this is the normal clunking that everyone has talked about in threads past. Let me begin...while coasting in the staging lanes with the truck in neutral, I hear and feel two clunk noises right under my feet/front drive shaft area. I don't feel anything in the wheel. No biggie, I discount it as a bumb and I go on with my run. On the next pass while accelerating down track right around the 2-3 shift, I hear it and feel it again...just one this time. After the finish line, I pop it into neutral and I coast through the shut-down area...I hear and feel 3-4 clunks then it goes away. I go up for my next pass and no clunking through acceleration but this time, past the finish line I leave it in 3 and just coast off the gas and I hear and feel multiple clunking and clanking, then it goes away. I turn off track and drive to the pit with no clunks at all. The question? WTF is going on here? Could it be the steering shaft thing even though it happened when I was going straight? I checked the u-joints for the front drive shaft and they appear fine. Any ideas? Quote Link to comment Share on other sites More sharing options...
rwoodards Posted April 27, 2009 Report Share Posted April 27, 2009 Ok, I've done extensive searches and I don't think this is the normal clunking that everyone has talked about in threads past. Let me begin...while coasting in the staging lanes with the truck in neutral, I hear and feel two clunk noises right under my feet/front drive shaft area. I don't feel anything in the wheel. No biggie, I discount it as a bumb and I go on with my run. On the next pass while accelerating down track right around the 2-3 shift, I hear it and feel it again...just one this time. After the finish line, I pop it into neutral and I coast through the shut-down area...I hear and feel 3-4 clunks then it goes away. I go up for my next pass and no clunking through acceleration but this time, past the finish line I leave it in 3 and just coast off the gas and I hear and feel multiple clunking and clanking, then it goes away. I turn off track and drive to the pit with no clunks at all. The question? WTF is going on here? Could it be the steering shaft thing even though it happened when I was going straight? I checked the u-joints for the front drive shaft and they appear fine. Any ideas? Check the transfer case, I had the same thing checked my transfer case there was a bunch of metal shavings in it. I am pretty sure my viscous coupler burnt up. Hope this helps. Rob Quote Link to comment Share on other sites More sharing options...
chpspecial Posted April 27, 2009 Report Share Posted April 27, 2009 could it be exhaust back fires Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 27, 2009 Author Report Share Posted April 27, 2009 could it be exhaust back fires I guess it could be but it has never done it before. Plus, on the last run, the noises were in succession and very rapid almost like something broke and was clanking along the bottom. It eventually stopped though without me doing anything which is what's confusing me. Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 27, 2009 Author Report Share Posted April 27, 2009 Check the transfer case, I had the same thing checked my transfer case there was a bunch of metal shavings in it. I am pretty sure my viscous coupler burnt up. Hope this helps. Rob Do you have a part number? And, was it difficult to replace? Anyone else have any theories??? Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 27, 2009 Author Report Share Posted April 27, 2009 Bump Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 27, 2009 Author Report Share Posted April 27, 2009 Well, since theories aren't pouring in like I expected them to, how about this question? Has anyone experienced the steering shaft clunk while going straight? Is that common? A couple of times I coasted through the staging lanes in neutral with truck turned off so I had to manually steer...could that have helped it along? The first time I heard it, I was going slow, just coasting. The two worse times were on deceleration...Any ideas????????????????? Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 28, 2009 Author Report Share Posted April 28, 2009 50 views and no other thoughts huh? Well, I guess I'll just start tearing shit apart! Quote Link to comment Share on other sites More sharing options...
detjoe Posted April 28, 2009 Report Share Posted April 28, 2009 Viscous Coupling TestTools Required J 45382 Transfer Case Tester To determine if the viscous coupling is operating correctly, use the following test procedure. Testing the viscous coupling operation by removing a propeller shaft and driving the vehicle will cause the viscous coupling to fail. The test will determine if the viscous coupling is faulty from a totally locked up failure, or if the viscous coupling fluid has leaked out from being severely humped. Important The Viscous Coupling Test is very sensitive to the temperature of the transfer case. If the transfer case is very hot, the time to turn will be faster. If the transfer case is cold, the time to turn will be slower. 1. Operate the vehicle for 24 km (15 miles), or until normal operating temperatures are reached. 2. Set the parking brakes for the rear wheels. 3. Position the transmission in neutral. 4. Raise the vehicle. 5. Remove the front propeller shaft. 6. Install the J 45382 into the transfer case front output shaft. 7. Using a torque wrench at 11 N·m (100 lb in) on the J 45382 , turn the front output shaft. 8. Note the length of time it takes to turn the front output shaft the 90 degrees. If the front output shaft turns slow, with resistance, and takes at least 10 seconds, the viscous coupling is operating correctly. If the front output shaft will not turn, the viscous coupling or the planetary carrier assembly could be locked-up. If the front output shaft turns easily, and the 11 N·m (100 lb in) cannot be obtained, the viscous coupling is faulty. http://www.wtfba.org/temp/NVG-149.pdf hope this helps. Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 28, 2009 Author Report Share Posted April 28, 2009 Thanks! Question? Would the truck still run strong and shift correctly if the coupling was toast? When I heard the clanking the worst (decelerating and coasting) was right after my quickest pass of the day so I know she ran strong. Quote Link to comment Share on other sites More sharing options...
detjoe Posted April 28, 2009 Report Share Posted April 28, 2009 My first guess was exhaust hitting the truck, but then on decel...shot that idea. I have not had the clunk going stright, I really dont think so on a nice surface like a track, maybe over bumps. Worn motor mounts allowing the engine to move too much and alllow the exhaust to hit the floor? YOu have LT headers?? Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 28, 2009 Author Report Share Posted April 28, 2009 My first guess was exhaust hitting the truck, but then on decel...shot that idea. I have not had the clunk going stright, I really dont think so on a nice surface like a track, maybe over bumps. Worn motor mounts allowing the engine to move too much and alllow the exhaust to hit the floor? YOu have LT headers?? Yes, I have LT's and I wouldn't say the dragstrip is bump-less! All of these examples sound great but the one that really baffles me is when I first heard it coasting through the staging lanes at maybe 5mph. Quote Link to comment Share on other sites More sharing options...
detjoe Posted April 28, 2009 Report Share Posted April 28, 2009 UJoints and wheels berings would also be on my list to check once I got the truck jacked up. Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 28, 2009 Author Report Share Posted April 28, 2009 Checked the u-joints briefly. I will check them more thoroughly when I get under it this weekend. I have been looking on PT.net and several have said that a simple transfer case fluid change and a lube of the slip yokes will fix any clunking. I am going to try that because I must admit, I am a bit lazy when it comes to T-case maintenance unlike the rest of the truck. Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted May 2, 2009 Author Report Share Posted May 2, 2009 Can't find the clunk!!! I got under the truck to day with the intention of changing the t-case fluid but I couldn't get the drain and fill plugs loose (is there some kind of friggin secret to this?). So, while I was under there I changed the front diff fluid and checked all of the u-joints and stuff. Went for a drive and boom, CLUNK very loud when I was OFF the gas. I even felt it in the steering wheel. I was going straight at the time. Turned around, felt no clunk in the wheel )maybe some minor little pops) started down the road again and CLUNK, felt it in the wheel again. Could this be as simple as the steering shaft clunk? The truck drives fine and has no loss of power when the clunk occurs but so far I have only felt it when going straight which I would think would rule out the steering shaft. Any ideas would be appreciated. Quote Link to comment Share on other sites More sharing options...
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