Hook n ladder 1 Posted May 28, 2009 Share Posted May 28, 2009 I have a 98 CH613. Last year the engine (427hp) was replaced with a Mack Reman engine. Since the "new" engine was installed there is a vibration when under load in lets say 4th 5th 6th gear (10 speed fuller). It feels like I'm driving over rumble strips. It's most notable in 5th. The entire truck shakes and it feels like the dash board is going to shake apart.When I'm bobtailing there is no vibration and when pulling my dump trailer empty the vibration is there but not as noticeble as when I'm loaded.The Mack shop that did the install thought the clutch wasn't indexed correctly when the motor was installed. They "re-indexed" the clutch but that did nothing. They re- tightened motor mounts and that had no effect. The truck needed a few u-joints and a center bearing. Nothing has changed.Any ideas? Anyone have this problem? Does the clutch need to be re-indexed again? The shop doesn't think so but one mechanic said it could be in 1 of 4 possible positions.Thanks Quote Link to comment Share on other sites More sharing options...
rw613 Posted May 28, 2009 Share Posted May 28, 2009 vibration damper maybe Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 28, 2009 Author Share Posted May 28, 2009 What is it? Where's it at? Sorry I'm unfamiliar. Quote Link to comment Share on other sites More sharing options...
rw613 Posted May 28, 2009 Share Posted May 28, 2009 What is it? Where's it at? Sorry I'm unfamiliar.on the end of the crank Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 28, 2009 Author Share Posted May 28, 2009 The harmonic balancer. Is it the same thing???? Quote Link to comment Share on other sites More sharing options...
Rob Posted May 28, 2009 Share Posted May 28, 2009 The harmonic balancer. Is it the same thing????Yes, they are the same item. Different names for the same thing. The power pulses transmitted to the crankshaft from the piston/rod combination sets up harmonic vibrations through the crankshaft. The dampner, or balancer is installed to counter these harmonic vibrations to both smooth the engine while running to relieve the crankshaft of torsional stresses preventing cracks, and ensure a long service life of both the shaft itself, and friction bearings. Uncontrolled harmonic vibrations will quickly render a crankshaft scrap from the minute cracking that will happen.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment Share on other sites More sharing options...
MACKS Posted May 28, 2009 Share Posted May 28, 2009 I had one go bad on a 237 once the result was some very serious vibration in the higher gears with a load on and when pulling a hill. Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 28, 2009 Author Share Posted May 28, 2009 The new engine did come with a new harmonic balancer. The shop said it can't be that because I should have the vibration all the time which I don't. Quote Link to comment Share on other sites More sharing options...
fjh Posted May 28, 2009 Share Posted May 28, 2009 The new engine did come with a new harmonic balancer. The shop said it can't be that because I should have the vibration all the time which I don't.Have your ride height checked possible drive line angle problem!Clutch replaced? flywheel ground? The vib you have is likly unrelated Unrelated to the engine in my opinion But you never know! Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 28, 2009 Author Share Posted May 28, 2009 They did re-use the old clutch (30% worn). Quote Link to comment Share on other sites More sharing options...
David Posted May 29, 2009 Share Posted May 29, 2009 Make sure the drive shaft is timed. Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 29, 2009 Author Share Posted May 29, 2009 What do you mean? How can changing the motor affect the drive shaft? Unless I was going from a 237 to a 460. I guess the new motor is putting out it's rated hp and the old one was probably doing a bit less.Hey fjh...the shop also thinks it's unrelated to the motor.Other than the vibe the new motor runs like a s.o.b. Quote Link to comment Share on other sites More sharing options...
bts-4120 Posted May 29, 2009 Share Posted May 29, 2009 Make sure the drive shaft is timed.thats what I would be thinking too bet the mechanic was not paying to much attention when they put the new u joints and carrier bearing in Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 29, 2009 Author Share Posted May 29, 2009 There was no difference before or after carrier bearing or u-joint change. Quote Link to comment Share on other sites More sharing options...
fjh Posted May 29, 2009 Share Posted May 29, 2009 thats what I would be thinking too bet the mechanic was not paying to much attention when they put the new u joints and carrier bearing inWhy was the drive shaft out???If it was that is a possiblity!If your having a shutter at aprox 40 mph 6 and seventh check the ride height! Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 29, 2009 Author Share Posted May 29, 2009 The shaft was out when they replaced the center bearing. I don't get the vibration at higher speeds. Its usually around 20-30. Anything done to the driveline made no difference. Anything done at all made no difference (so far). All I know is this ...old motor no vibe, new motor bad vibe . Quote Link to comment Share on other sites More sharing options...
Maxville Truck Posted May 29, 2009 Share Posted May 29, 2009 Ride height and driveshaft phasing....!!!! Quote Link to comment Share on other sites More sharing options...
fjh Posted May 29, 2009 Share Posted May 29, 2009 Ride height and driveshaft phasing....!!!!Mack Diffs ???? Try locking the power divider out! Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted May 29, 2009 Author Share Posted May 29, 2009 No. They're Eaton diffs. I was also incorrect. I get the vibe between 5-10 mph (maybe up to 12 mph). After that it's gone. Quote Link to comment Share on other sites More sharing options...
fullfuel01 Posted May 30, 2009 Share Posted May 30, 2009 check the height of your susp. if it's air ride... check your tires, might be as stupid as a bump in one!! Quote Link to comment Share on other sites More sharing options...
Mack Doctor Jr. Posted September 18, 2009 Share Posted September 18, 2009 I know its been said already, but those drive shaft yokes must be in time or they work against each other. I've seen a lot of times its usually the problem.. Quote Link to comment Share on other sites More sharing options...
Noid93 Posted September 18, 2009 Share Posted September 18, 2009 Easy ride height check-- Dump the air in the suspension when it is shaking. IF the shaking goes away, it is set to High(lower the susp. on leveling valve). If it doesn't go away, the ride height MAY NOT BE set high enough(if it is a driveline issue at all). Easy easy way to check for ride height isssue.... Quote There Is No Replacement, For Displacement!!!!! Link to comment Share on other sites More sharing options...
mackdaddy1911a1 Posted September 20, 2009 Share Posted September 20, 2009 I had a vibration similar to your problem and it was caused by ride height. Mine was to low have that checked. However I realy think it has to do with the new engine...like you said old engine no problem new engine bad vibration.The only good thing is IF you had it installed at a Mack dealer and it tears something up they will fix it. I had the harmonic balancer come off a week after I had a new cam installed. The dealer paid for the tow and the repairs. There has to be a way to test the engine's harmonic balancer to find out if it is bad. Good luck and please let us know what you find and how you got it fixed. Quote THE GREATEST NAME IN TRUCKS MACK TRUCKS Link to comment Share on other sites More sharing options...
QCDriver Posted September 29, 2009 Share Posted September 29, 2009 I had an '01 Vision in the shop for some electronic problems once. I got the truck back within in a few miles loaded started to shake at56-59. It only shook only while loaded also. Mack had it for a month swapping parts,only to find ride height out.Did not make sense that it went out, while in the shop for unrelated problems.To this day it still rides nice now according to new owner.Hope this helps and you get it fixed. Quote Link to comment Share on other sites More sharing options...
hatcity Posted September 29, 2009 Share Posted September 29, 2009 IF you have air-ride, watch air gage. You may have a bag blown out. When you hit a bump, chassis drops, driveline vibration.OR, this may sound crazy, but check for broken axle. Place I worked had "the worlds best driver" Truck had serious vibration occasionally. Pulled trans, and checked out OK. Pulled an axle, broke. This driver also snapped another the same week. Quote Success is only a stones throw away.................................................................for a Palestinian Link to comment Share on other sites More sharing options...
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