Keeping Driveline in phase ?

[rjewkes]

Why is this important, what happens if it is out of phase allready?

how do i keep it in phase if i pull the very rear half of the two peice shaft? do i just mark one side of the rear end and the rear section at the u joint area? if it's out of phase now is it as simple as marking it as it is and swapping it during install? how would i know if it is out of phase?

[Whateverman]

the drive shaft is balanced with both halves connected together & so if they aren't lined up with each other like they were when they were balanced there will be an imbalance and vibration/wobbling etc,etc
just mark a line on both the shafts so you line them up the same way you took em out
(usually the balance weights are all in line,if i'm screwing around changing transmissions or whatever and have to use a different front or rear shaft than i started with i just line the weights up...worked so far for me)

[Donnie]

Just a slight addition to the previous post:
Drive line phase, has to do with the U joint's, ALL OF THEM being in line with each other.
If you lay the shaft's on the floor, ALL of the U joint's must be square with each, in other words, all of them must be flat on the floor, it is easy to be off 1 spline when you split the shaft's.....you can see this when laid together on a flat surface (floor).
This inhibits the flexing of the shaft & will show up in vibration, & early u joint failure.Plus wear on the spline's.
Constant velocity joints are the compound u joint assy.'s that you see where 2 u joint's are connected in one housing..These type are less likely to be on your truck, but are a constant velocity joint, where as the regular ujoint is cycled in 90 degree cycles, only flexes 4 ways.
So 2 shaft's connected+++all joints must flex the same way...I.E. being in phase
If Whateverman is using the weights to phase the shaft's & it has worked for him..........he is lucky.....If you are mixing 1/2's from 2 different shafts, this will not work
Balance & phasing are 2 different ....term's.............Donnie

[guhfluh]

That's good info Donnie. I just changed the clutch in my truck and I wondered about phasing, but since the slip joint spline in my 2 part shaft wasn't keyed and I didn't mark anything. I didn't know how to line it back up. I'm going to have to crawl under my truck and look now.

[Whateverman]

forgot to mention the u-joint thing,thanx Donnie
And just for the record...yes i've mixed and matched the back and front halves numerous times over the 20 or so yrs i've had my truck and have had no probs at all ...ever.

[rjewkes]

So primarely phase has to do with the alignment of the u joints and their ability to flex the same way, good to know i thought ment something like wich side of the shaft faced wich direction

[Builder]

Having read most of the remarks on driveshaft phasing there is one question I have not heard or answered.first a quick update 70' f350 dump just got it on the road, driveline vibration at 45' pulled driveshaft , 2 piece, took it to a mechanic, said its fine.he told be to phase it I did, but still have vibration , thought maybe given the year someone rotated the driveshaft half ,tried that more vibration this time at 30 mph, but this is my question the sight line of the 2 piece from rear end to trans input is it straight of slightly off at the steady bearing?

[Ranchero50]

The quick and easy answer is to put the rear on jack stands and run it at speed while watching the drive shaft for vibration. Damn near always it'll show you what's wrong. Might be a wheel or something else so be open minded and safe when you do it.

I'm also pretty sure all carrier bearing slip joints have an index spline so you can only put them together one way.

[Builder]

The quick and easy answer is to put the rear on jack stands and run it at speed while watching the drive shaft for vibration. Damn near always it'll show you what's wrong. Might be a wheel or something else so be open minded and safe when you do it.

I'm also pretty sure all carrier bearing slip joints have an index spline so you can only put them together one way.

what we did was print off a copy of a diagram indicating the proper drive line phasing method, then we removed the driveshaft in one piece and set it up in a vice on one end and a couple of steel tubing stands on the other checked with a level both sides of the drive shaft joints. we did not find an index spline, on this one. (checked)

[390bump]

Took my drive shaft out to have it balanced and all the u joints replaced (and support bearing). Guy at shop said the drive shaft was bent a bit so he straightened it (said this can be done once only). Put it back in and... WOW Drives smooth as glass now! Had a vibration that was getting worse... Guy at shop said it is very common for driveshafts to get this wobble over the years. BTW, looks like I was not out of phase in my alignment before hand.