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Indexing the drive shaft... What's this ???

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My truck also has the vibration problem. The dealer has no ideas. I read TDR #45 page 48 and will pass this along to the dealer. Some post's on here mention having their problem fixed by indexing the drive shaft. Would someone please explain this to me. Thanks... ... .
 
i think it is only applicable to those that have a 2 piece rear shaft. i can't see any reason to do so on a single piece shaft. there is nothing you can index on a single shaft. on a 2 piece with a slip joing at the carrier, then it can be indexed [you could do it in your own driveway too... ]
 
First we need to assume that all parts are out of balance to some extent.....



If the out of balance of the clutch, flywheel, driveshaft is aligned... . the total amount of out of balance will exceed the specifications, even though the single out of balance for any one item is fine.....



To index the flywheel, its removed and turned 180* on the crank... on those trucks that allow this... some flywheels only fit to the crank one way.....



To index the clutch cover... . remember the disc locks to the cover each time in a different location so it doesn't matter... . you un bolt it and turn it 180* on the flywheel... .



and to index the drive shaft you remove it and reinstall it 180* to the transmission... .



Its understood that each time the clutch engages and dis engages, the drive shaft is in a different relationship to the clutch cover... and flywheel... however this has shown to get rid of some vibrations... .



The above is outlined in failure analysis in HD truck applications..... for drivetrain vibrations... .



Jim
 
jelag said:
First we need to assume that all parts are out of balance to some extent.....



If the out of balance of the clutch, flywheel, driveshaft is aligned... . the total amount of out of balance will exceed the specifications, even though the single out of balance for any one item is fine.....



To index the flywheel, its removed and turned 180* on the crank... on those trucks that allow this... some flywheels only fit to the crank one way.....



To index the clutch cover... . remember the disc locks to the cover each time in a different location so it doesn't matter... . you un bolt it and turn it 180* on the flywheel... .



and to index the drive shaft you remove it and reinstall it 180* to the transmission... .



Its understood that each time the clutch engages and dis engages, the drive shaft is in a different relationship to the clutch cover... and flywheel... however this has shown to get rid of some vibrations... .



The above is outlined in failure analysis in HD truck applications..... for drivetrain vibrations... .



Jim



is that re indexing :D
 
JHardwick said:
I've not looked under a new Dodge with a one piece drive shaft. But, one piece shafts used to need indexed too.



indexed against what though?



with only 2 u-joints on the single piece driveshaft, that are both fixed solidly at one end to the common driveshaft [no slipjoint on the shaft], there isn't anything to index. the phase of them cancel each other out because of the solid common driveshaft.



i can not see at all how a single piece like in our trucks needs to be indexed [the slip yoke on my truck is in the transfer case output, not on the shaft]



now if it was a single shaft with a slip joint on it, then yes you need to index it, but on our trucks with single d-shafts, not an issue
 
Indexing is getting the shaft runout optimized. You need a dial indicator to see what the runout is at the front, middle and rear of the shaft. The service manual generally gives . 015-. 020 as being in spec. On the 3rd gen front shaft you want to see between . 005-. 010 for the least vibration.

Once you know the runout, move one end of the shaft 180 degrees and measure again. If better move 90 degrees one way, measure, then 90 the other (from the 180) way and leave it at the spot that provides the least runout. The new yoke on the front can only be installed two ways. I believe the rear end of front shaft can be moved into eight positions. But just like the front, measure, move 180, measure, move 90 both ways, etc.

Without the dial indicator you can mark the stock spot and move it 180 and drive it. It takes a lot longer, but achieves the same result. If you are going to try it, buy a 3" long t40 torx bit so you do not strip out the bolts. The front ones are a bear without the long bit. If you have the dial indicator, you only need to install one bolt while measuring.

When done, install new bolts or apply more lock tite.
 
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