Hey folks. 1993 m998 6.2 liter three speed has developed an engine vibration between 50 and 55 mph. Runs smooth outside of that range. I don’t have a Tac so not sure of the rpm but it does it out of gear also if you rev it up. When checking the motor mounts I noticed an engine oil leak now where there was none before. Am I doomed or has anyone else run into this?
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Vibration issue
- Thread starter TXGunner
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rcamacho
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Tire balance?
Driveshaft u-joint wear/impending failure?
I recently replaced all u joints and carrier bearing on my M998. Carrier bearing was worn. One u joint was brinneled dry and going to fail. Several others were worn/loose.
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Driveshaft u-joint wear/impending failure?
I recently replaced all u joints and carrier bearing on my M998. Carrier bearing was worn. One u joint was brinneled dry and going to fail. Several others were worn/loose.
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I thought the same but it vibrates at a certain RPM in park. Then there’s the oil. Maybe tie rod?
Action
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Were you trying to say that it vibrates at a particular rpm range, no matter if moving or sitting still? Your hmmwv doesn’t have Park.
Yes. When the transmission is in neutral and engine at higher RPM the vibration is there but only at a certain range then it goes away. Or at 50-50 mph. Same RPM range. It’s in the engine, not the drivetrain.
rcamacho
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Ah, maybe harmonic balancer or torque converter failure?
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Ah. Maybe. Sounds like a trip to the shop. I don’t have the space to tear into the engine unfortunately.
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I recently had a vibration with a 6.5 in a M1045A2 and the outer ring on the harmonic balancer was visibly wobbling. Take a look with it running and see if it's running true. You might see also that the rubber is degraded. Not hard to replace...
I also had another 6.5 with a vibration like you describe; that one had loose torque converter bolts.
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I also had another 6.5 with a vibration like you describe; that one had loose torque converter bolts.
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Harmonic balancers supposedly break free of their woodruff keys and can loosen on the 6.2 engines. I would immediately stop driving and check! If that is the problem, replace the harmonic and re-install with updated longer bolt to secure it.
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I agree with the rest, sounds like a loose/defective harmonic balancer
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put a new harmonic damper on Her, nothing else.
We wish Fluid damper would make them for us
We wish Fluid damper would make them for us
I thought Fluidampr DID make a harmonic balancer for 6.2? #800191? Or #800141?
TOM R
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i have a vibration thats intermittant comes and goes from say 35 mph and up, sometimes it shakes the truck horribly, ive moved tires around with no change, checked front end, serviced the outer hubs and all fluids, checked torque on the cv bolts and checked ujoints, 1992 6.5 na
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Tom, did you read through this thread?
TOM R
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Yes, and I believe I checked the damper before, but can check again , I do know one of my low speed shakes is flat spot in at least one tire that goes away after a mile or so, I have 12 bolt rims with the wrangler m/t tires and run flats in them
I just ran an errand and did run the rpm up in neutral without and odd shake or vibration
I just ran an errand and did run the rpm up in neutral without and odd shake or vibration
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Have you tried Centrimatics and checking your alignment?
TOM R
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I know my alignment was off significantly but adding the winch,luverne bg , sup armored x doors and armored grills seems to have brought the front back down and fixed the camber and toe, though I can check the toe once snows gone
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Alignment can easily cause speed related vibrations. So can unbalanced wheels OR wheels dirty with hidden deposits of snow/ice/mud.
TOM R
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I don't off road this vehicle and it does it in nice weather too, I could see a tire balance issue but this comes and goes , say I hit 50mph on speedo, truck may shake bad like I have a flat I slow down some and speed back up ,gone or very minimal
I have serviced the outer hubs and checked the torque on the cv bolt in port holes but I did not pull the inspection plates and check that nut that holds the wheel hub on, it did appear they were previously apart