| Author |
Message |
    
Lawrence Tilly (L_Tilly)
| | Posted on Sunday, February 02, 2003 - 09:42 am: | 
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My 96 Disco (106k miles) has started making a new noise & vibration, and I hope some DWeb input could speed up my diagnostic. Here are the symptoms:
1. It sounds very "throaty". My first thoughts were that my exhaust was going, because it really does sound like that (and comes from the lower central to rear area of the truck). I need to replace my O2 sensors (checked the code), so I thought that could be a contributor. However, I think I ruled out exhaust (see #3 below).
2. It occurs when I apply gas of more than about 1/4 - 1/3 of the pedal-travel distance. However, it runs perfectly silent (except for normal whine and road noise) within that limited range. Basically while accelerating up to speed it's there, but once I hit a limit between 35 - 55 I can usually drive without hearing it again. At 65 I have to use enough gas where it comes and goes a lot.
3. If I put the truck into neutral at any speed I can apply as much gas as I want and not hear it. To me this rules out an exhaust issue. Correct me if I'm wrong.
4. It happens through all forward gears (I have not tried going fast enough in reverse to test it there). While the truck shifts gears (auto) or I control it, there is little effect on the noise. I do not hear enough of a change to even say if there even is one.
5. The Rotoflex does not show cracking, but there are a lot of "threads" coming from around where the bolts pass through. When this Roto was put on (about 45k+ miles ago) the original one had a lot of cracks and I felt some signficant thuds while applying gas and changing gears. This feels different.
So...any ideas or suggestions? If I can't nail it down myself I'll probably take it into a shop to diagnose, but I have hope I few people out there have had something similar before. I do hope it's exhaust because that's covered by Midas, but with the behaviour #3 I don't know how it could be.
advTHANKSance!!!
Lawrence lnctilly@metrocast.net
96 Disco "Beowulf" NH,USA |
muskyman
| | Posted on Sunday, February 02, 2003 - 10:56 am: |
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sounds like exhaust...the aluminum donut gasket infront of the big center muffler is a flat slide in gasket/coupler that has a single ridge around it to locate it. mine had burnt off the center ridge in one spot and exhibited very similar characteristics as you described.vibes at different speeds and throaty on the gas and quiet off
you'l need (2) 3/8ths x 1 1/4 bolts. then just cut the old bolts off remove the old coupler gasket replace with new and rebolt it tight.
Nathen stocks the coupler/gasket, the local parts stores and muffler places dont, its kinda different then most so using the correct one will make sure to quell any vibrations and leakage.
good luck |
Lawrence Tilly (L_Tilly)
| | Posted on Sunday, February 02, 2003 - 11:18 am: |
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Musky,
Considering that if I put the truck in neutral (either in my garage or at highway speeds) and rev the engine without any noise / vibration, does that still sound like it could be caused by the gasket?
-L |
muskyman
| | Posted on Sunday, February 02, 2003 - 11:36 am: |
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yep...mine only did it at certain speeds and load conditions...plus the jount did not apear loose..the only outward sign was a throaty sound and a very small darkened area about the size of a dime next to the joint.
exhausts can make so many different sounds as it resonates so its hard to ever know for sure but that does sound alot like mine sounded .
oh yea mines a 94 now at 90k |
Lawrence Tilly (L_Tilly)
| | Posted on Sunday, February 02, 2003 - 11:38 am: |
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Thanks. I'll take a look at that area of the exhaust when I'm under the truck later today. I hope you're right and that's all it is!!!
-L |
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