ws721 Posted August 10, 2014 Share Posted August 10, 2014 Truck has Mack 6 spd with a .62 overdrive. CRD 92 rears 5.73 ratio. truck has Neway susp I have been chasing this vibration for some time. I know what I should do is change tranny and rears to slow down drive shaft rpm. I have been told that I will never get rid of all the vibration due to the incredible shaft rpm. What im asking is this true? I have replaced all U joints, Slip joints. There is a little movement in output yoke in front drive. Any ideas short of better ratio and tranny? Quote Remember if it's got a hood it's no good! Link to comment Share on other sites More sharing options...
james j neiweem Posted August 10, 2014 Share Posted August 10, 2014 drive shafts can be removed and balanced on a machine by adding or removing small weights. If the imbalance is at your cruising speed this can be mechanically harmfulso you want to make sure there is no imbalance at this speed. You may experience some imbalance at a particular rpm as you run up through the gears but this will go away as youmove on up the rpm range. You can check the bearing play in the tranny and rear end with dial indicators. Hopefully its not time for transmission bearings and hopefully you are notmissing any gear teeth. Quote Link to comment Share on other sites More sharing options...
mrsmackpaul Posted August 11, 2014 Share Posted August 11, 2014 the drive shaft has to have phase angles set you might need to check them jump on to google theres plenty of information the one that I dont see is when you have more than on drive shaft in a row the uni's should not be in a straight line as they interfear with each other they should be set lagging behind the front shaft one tooth as you are coming back from the transmission have had this cause problems for me in the pastas to the other part of the question the drive shaft not vibrate at all no matter whats speed oh and make sure the big bolt in the gear box yoke is tight this has also caused me grief before Paul Quote Link to comment Share on other sites More sharing options...
dog catcher Posted August 11, 2014 Share Posted August 11, 2014 Drive line angle's do to a change in ride height. Also so a clutch can give a bad vibration. Quote Link to comment Share on other sites More sharing options...
ws721 Posted August 16, 2014 Author Share Posted August 16, 2014 Ride height has been a sore subject. I have called several folks including the people who took over Neway and received several different answers. Experimiting has been the best help. Quote Remember if it's got a hood it's no good! Link to comment Share on other sites More sharing options...
ws721 Posted August 16, 2014 Author Share Posted August 16, 2014 the drive shaft has to have phase angles set you might need to check them jump on to google theres plenty of information the one that I dont see is when you have more than on drive shaft in a row the uni's should not be in a straight line as they interfear with each other they should be set lagging behind the front shaft one tooth as you are coming back from the transmission have had this cause problems for me in the pastas to the other part of the question the drive shaft not vibrate at all no matter whats speed oh and make sure the big bolt in the gear box yoke is tight this has also caused me grief before PaulSo are you saying the driveshaft should be one tooth off in the slip joint? Thanks for the response gentlemen Quote Remember if it's got a hood it's no good! Link to comment Share on other sites More sharing options...
Solution Popular Post j hancock Posted August 16, 2014 Solution Popular Post Share Posted August 16, 2014 This Spicer info may help. It deals with phasing, acceptable angles for the drive shaft and pinion angles and multiple shaft issues.http://65.170.161.218/~spicerpa/sites/default/files/pdf/driveshaft_installation.pdf 3 Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
jdfordhd Posted August 16, 2014 Share Posted August 16, 2014 With an engine RPM of 2100 turning an OD ratio of .62:1 , the driveshaft is turning 3387 RPM..! That's hummin'...! The Spicer document that j Hancock linked for us is an excellent read. The tailshaft centerline of the trans must be parallel to the input shaft centerline on differential. I found a vibration once because this alignment was wrong. Had to shim the carrier bearing for the fix. Quote "If it ain't got a motor, I ain't interested.!!" Link to comment Share on other sites More sharing options...
mrsmackpaul Posted August 16, 2014 Share Posted August 16, 2014 So are you saying the driveshaft should be one tooth off in the slip joint? Thanks for the response gentlemenIm not sure what you call a slip joint Im guessing its the spline the uni crosses on each end of a section of shaft must be in alingement but on a body truck with multiple shafts they shouldnt at least that is what it said in a old work shop manual I had cant seem to find it had a look once for someone else a while ago but as you come back towards the diff as you go to each seperate shaft it should be on notch lagging behind the previous one I had this problem once the drive shaft people had all sorts of excuses as to what was causing it from engine mounts to faulty gearboxes to diff's but it had worked fine before any work was done on it so it still should work find anyway thats what I found and it worked fine since Pauloh yeah it got two new center bearings from them and thats when the problem started Quote Link to comment Share on other sites More sharing options...
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