The Stovebolt Site Forums The Shop Area Engine Shop In-phase drive line

Happy Thanksgiving one and all. I am trying to get an image in my mind as to how to go about checking to see if a driveline is in phase. My earlier post about the severe vibration since restoring my '53 3/4ton leads me to believe that the problem is with the driveline being out of phase. It is all installed, so what's the easiest way to check it? Is it possible to check without dismantling the driveline? I'm curious as well what specifically needs to be in phase. I never changed the driveline, but I did remove it and tore it down. All new u-joints and seals. This truck has the two-piece driveline with the front section enclosed and a carrier bearing in the center. Am I correct in assuming nothing needs to be in-phase forward of the carrier bearing? The shop manual talks about making sure the front of the rear section of the driveline is in phase with the tail end of the rear section. I did not remove the portion of the driveline that slides to compensate for movement in the truck. I'm not sure if that is splined inside or not. Any help with phasing the driveline would be appreciated. The manual does a poor job of explaining it and when I tried searching for previous posts, I keep getting a message that indicates the page is expired. I have to start the search all over each time I look at one individual post. thanks in advance for any help.

The quick answer.
For a single piece driveshaft the two yokes need to be orented the same way.
With the driveshaft out of the truck and the u-joints out you can slide a steel bar in each end, if one bar is level to the ground the other one better be also.

You can see if it is about right while still in the truck by just looking at it.

Grigg

the following I cut and pasted from this thread
https://www.stovebolt.com/ubbthread...g&topic=0&Search=true#Post155466

These two manuals will help with any and all driveshaft installation and geometry questions:

http://www.roadranger.com/Roadranger/servicesalesliterature/serachresult/RR_DSAG-0200

http://www.roadranger.com/Roadranger/servicesalesliterature/serachresult/RR_DSIG-3311

Most people have there own way of explaining it, some right, some wrong, these Spicer manuals can't be argued with, after all, back in 1904 Mr. Clarence Spicer did invent and patent the U-joint we still use today.

Grigg

Basically it refers to the yokes being in alignment with each other. In other words, the u-joint on the rear shaft slip yoke
must be installed onto the slip stub so that it is in the same position as the front joint or "in phase". Any other position will not transmit power smoothly and create an imbalance situation. That will probably mean loosening the ball connection at the tranny and checking the postion of the front yoke and then connecting the rear slip so that the joints are aligned.
A little hard to explain w/o a diagram or photo but I'm sure you'll understand once you take a good loook and think about it.

On these front enclosed two piece units it's wise to paint or mark a stripe on the slip stub and the slip yoke so that they go back togethaer as they came apart.

Thanks for the Dana/Spicer link Grigg, ANOTHER manual that I have to print out for the library!
Yes phasing is critical and angle is important as is indicated by the charts. However, I just can’t help but think of the drive shaft angles I saw on a video of off-road four wheelers at my nephews a few weeks ago.
Must be that they just don’t expect more than 10% of the life expectancy out of their drivelines and they never get much over 5mph climbing over rocks.

As fur as your 3600 drive line Rick, ya know, if you read the Shop manual, it says nothing about aligning the front and center u-joints. Since there is just the tiniest bit of movement between them I can’t see where phasing is an issue with them. The center and rear u-joints are another story because of the up and down movement of the rear axle. If the axle were solid then phasing would not matter there either.
Denny Graham
Sandwich, IL


Denny Graham
Sandwich, IL

Thanks for the posts guys. Denny, I tend to agree that's why the manual doesn't say anything about the front driveline phasing. I guess I'm going to have to wait until this busted leg heals and then get back under there and look at what I've got. Maybe the vibration isn't the driveline and is something more serious. I do know that when I crawled under there last and looked at the carrier bearing, I noticed that the bearing mounting bracket is a little off-center. I tried loosening the bolts there and moving it over, but it didn't budge. That tells me something isn't quite lined up, but I'm not sure what is causing that.

Rick..a carrier bearing being slightly off center will not effect vibration but is the the same as changing the up/down angle of shafts. It makes no difference if it's up/down or back and forth to the joint. It will be used on a rear end that has higher degree of C/L offset than the engineers want for total working angle. All joints should be set to cancel out the angle of the opposite end. If you didn't take the shafts apart it probably isn't your vibration problem I wasn't clear on what you meant to say about that aspect of things. It sounded as though you'd taken the rear shaft apart for rebuilding and therefore could have replaced it out of phase onto the midship stub shaft which would be a vibration problem.

Denny, ALL u-joints must be in phase with one another. Think of it this way..12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock. This must be the way to smoothly transmit power regardless of the number of driveline sections, be it 1 or 4 pieces. So it really has nothing to do with "movement" or the angle degree of a joint if I follow your meaning.

Ron..if a needle bearing is in the bottom of the cup it become impossible to replace the snap ring into the yoke but I've seen guys crush them in presses attempting to do it and even bend yokes.

I fully understand the concern one has when you see off roaders, mudders, monster trucks, etc. that have very high degrees of angularity. Your correct to assume the short life of these joints. When I had the driveline shop I used to have a customer who would go to mud runs on Sunday and leave his driveshaft by my front door so I could rebuild or replace it on Monday. This is one example of how short the life of improper drivelines can be. In this case it was too much power and steep angularity. But it illustrates how critical it is to match a lot of variables to make the things work as intended.

Okay now maybe we are getting to the source of the problem if I understand your post, Dave, about all of the joints needing to be in sync. You are correct in that I did not dismantle the rear driveline. I left the rear intact including what I guess is referred to as the slip yoke. However, from that point forward, everything was dismantled including removing the front U joint from the back of the transmission, pulling the drive shaft out of the casing (enclosed front drive line), and removal of the intermediate yoke that attaches to the front driveline just to the rear of the carrier bearing and mates with the slip yoke on the rear driveline. So, when I replaced the seals and re-connected the front u joint to the rear of the transmission, I then reconnected the front driveline but probably do not have the yoke to the rear of the carrier bearing in sync with the transmission u joint. Make sense? From the carrier bearing back as far as the rear drive line goes, nothing was dismantled. But if the u joint yoke behind the carrier bearing is out of sync with the transmission u joint, it sounds like that could be the problem. I'm curious as to why the shop manual doesn't talk about the need for these to be in phase though. <a href="http://photobucket.com" target="_blank"><img src="http://i152.photobucket.com/albums/s161/Rick_53/MVC-019S.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

<a href="http://photobucket.com" target="_blank"><img src="http://i152.photobucket.com/albums/s161/Rick_53/MVC-018S.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

Hope I did these right. The photos show everything I dismantled and maybe they will help in diagnosing the problem.

I guess I attached the photos wrong. Here they are.
[IMG]http://i152.photobucket.com/albums/s161/Rick_53/MVC-019S.jpg[/IMG]
[IMG]http://i152.photobucket.com/albums/s161/Rick_53/MVC-018S.jpg[/IMG]

Too bad you don't have a photo of the front driveshaft after you rebuilt it. The yokes MUST be aligned the way the yokes on the rear shaft are aligned. I guess the only way to check would be to peek inside the ball and see if the forward yoke on the forward shaft is aligned with the rear. Can you loosen the ball and slide it back enough to see the joint?

On a side note, where did you get your new u-joints for the rear shaft? Just changed mine and had a devil of a time finding one to fit the front yoke. Lots had the right size bearings and spiders, but the center web was too meaty and I couldn't get it installed. No problem with the rear... Kinda strange...

Yep, I'm sure now that the problem will end up being the front and intermediate yokes out of phase. I never checked this at all when I put the front driveline back together. The shop manual only referred to the back two being in sync. Anyway, it will require removal of the front driveline to get it put together the right way. I will likely need to get a new gasket set including the cork one as well. No problem though. Whatever it takes to do it right. Highflyer, the two u-joints for the rear shaft were the same on mine. Same number and a NAPA part at that. I had to remove the grease fitting, if I recall, in order to get the front one installed.