Bigdogtrucker Posted April 19, 2012 Share Posted April 19, 2012 My 673 has a vibration i'd like to fix.When you rev the engine it get's worse,idle's fine.Does not matter if the clutch is pushed in or not.Water pump is new,fan is straight also.Any other idea's what to look at??? Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/ Share on other sites More sharing options...
Mike Posted April 19, 2012 Share Posted April 19, 2012 My 673 has a vibration i'd like to fix.When you rev the engine it get's worse,idle's fine.Does not matter if the clutch is pushed in or not.Water pump is new,fan is straight also.Any other idea's what to look at???I've heard this situation before with these engines. I have several questions. 1. Is this your first Mack engine? 2. Did you start up a cold engine and gun the engine? 3. Have you changed to a different oil?mike Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115054 Share on other sites More sharing options...
leversole Posted April 19, 2012 Share Posted April 19, 2012 Make sure your harmonic balancer is straight and true, and the bolts are tight! Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115056 Share on other sites More sharing options...
Bigdogtrucker Posted April 19, 2012 Author Share Posted April 19, 2012 I've heard this situation before with these engines. I have several questions.1. Is this your first Mack engine?2. Did you start up a cold engine and gun the engine?3. Have you changed to a different oil?mike1.I've owned many B's with these engines in the past.2.I never rev a cold engine3.NO The balancer is on straight and looks to run true.What's on the inside of the balancer? Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115093 Share on other sites More sharing options...
220cummins Posted April 19, 2012 Share Posted April 19, 2012 Did you look at the front and rear engine mounts? Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115099 Share on other sites More sharing options...
Bigdogtrucker Posted April 19, 2012 Author Share Posted April 19, 2012 Did you look at the front and rear engine mounts?Fronts are nice and tight,rears look good as far as i can see.Wondering if it could be in the clutch?When i push the clutch IN it's a little noisy,no noise when it's out.(quad with double disc)Clutch works good,but was last replaced in the "80's.The truck never saw a lot of miles though,hauled equipment to and from the job sites. Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115102 Share on other sites More sharing options...
Bigdogtrucker Posted April 19, 2012 Author Share Posted April 19, 2012 Throwout bearing may be getting tired. Should be a grease fitting to get a little lube into it. I wouldn't think that would be the cause of vibration right off. If whole clutch assy. is worn could give a little vibe.Any way to check it out without pulling the trans? Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115104 Share on other sites More sharing options...
j hancock Posted April 19, 2012 Share Posted April 19, 2012 There is an inspection port on the top of the bell. The floorboards have to come out to get there. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115106 Share on other sites More sharing options...
Bigdogtrucker Posted April 19, 2012 Author Share Posted April 19, 2012 There is an inspection port on the top of the bell. The floorboards have to come out to get there.Thanks,maybe i can find someone local(CT/MA)to have a look at it.If i do end up needing a clutch what are the options? Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115107 Share on other sites More sharing options...
Kav Posted April 19, 2012 Share Posted April 19, 2012 Hi Bigdogtrucker - The fluid in the Harmonic Balancers can go hard when they get old and the balancer cannot centralise and this can cause a vibration. Over the years I have had to change several of them because of this. Best regards - Michael. Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115110 Share on other sites More sharing options...
Bigdogtrucker Posted April 19, 2012 Author Share Posted April 19, 2012 Looked up from the bottom and found this!Pressure plate seems to be off center.Bad plate,throw out bearing,both? Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115111 Share on other sites More sharing options...
j hancock Posted April 19, 2012 Share Posted April 19, 2012 Good eyes! That does look off. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115113 Share on other sites More sharing options...
Bigdogtrucker Posted April 19, 2012 Author Share Posted April 19, 2012 Good eyes! That does look off.I just looked at it again,i'm pretty sure the bad bearing is causing this. Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115114 Share on other sites More sharing options...
j hancock Posted April 19, 2012 Share Posted April 19, 2012 I just looked at it again,i'm pretty sure the bad bearing is causing this.Could be, I can't tell for sure in the photo. But there is misalignment. When the trans comes down, everything else can be inspected. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115115 Share on other sites More sharing options...
Bigdogtrucker Posted April 19, 2012 Author Share Posted April 19, 2012 Could be, I can't tell for sure in the photo. But there is misalignment. When the trans comes down, everything else can be inspected.Now i just need to find someone who can pull it out and replace it for a decent price.... Quote Link to comment https://www.bigmacktrucks.com/topic/24579-673-vibration/#findComment-115116 Share on other sites More sharing options...
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