Anyone know why 58-64 Chevy driveshafts are out of phase?

[DrJ]

They are two piece and one section is in phase and the other is out of phase. I think this is why there is a bunch of black magic calculations and trial and error shimming road testing and more shimming spelled out in the repair manual to keep them from "shuddering". I've had several cars, mostly Volvos that had the two pieces each in phase so I know it's not the "normal way to do it.
Anyone know why?
Anyone ever changed one to the Volvo setup to see if it worked better in phase?
(I know the splines won't let you do it on the Chevy, but a different shaft would.)

Volvo shaft (engine)---[0----shaft-----0]---2ndshaft---[0-(diff)

Chevy shaft (engine)---[0----shaft-----[0---2ndshaft---0]-(diff)

this - [0 - is the U-joint.
Chevy ignors the middle joint and in so doing makes it out of phase, unless there's some black magick about it I didn't learn in highschool physics.

Anyone up on this enough to 'splain it?

[manyolcars]

Columbus was an illegal Alien. >>>>>>>>>.but he didnt get a drivers license and he went back to where he came from

[SKR8PN]

I have never played with THAT particular driveshaft,but WHY won't it let you put it "in phase"? Is there a master spline on the yoke and collar? This does have a carrier bearing,correct?

[noboD]

Dr J., you just gave me an idea, Thanks. My '70 Ford truck has a droning vibration about 35-45 mph. 2 piece driveshaft, had new joints when I bought it. I'm going to check the manual. This might be my problem.

[flt-blk]

I can't remember too well, but I think the 2pc in my 55 S2D
was in phase on both sides.
TZ

[choprods]

I'm on the second shaft all three new joints and second carrier bearing-in 6mos![my 58El Camino]
I have about had it!I am thinking of replacing it with a long single shaft......

[safariknut]

DrJ:Are they 90 degrees out of phase or somewhere in between?I had a couple of 60 Chevrolets and the only problem I had was center bearing supports.After I learned the trick of installing them properly I never had a problem afterwards.
As to the other person who had a driveline vibration at lower speeds,one of the things I found out about the joints in my 55 Safari is if they are not ABSOLUTELY centered in the shaft(and they can be out a bit)they will vibrate.Mine came in at about 55 mph and was gone at just over 60.
I talked to the guys who made up my driveshaft(55 shaft w/ a 56 yoke)and they said that proper phasing AND absolute centering of the joints is essential to not only minimizing vibration but joint longevity.
For those who own one of htese cars and are not familiar with the proper procedure for installing the shaft:After it is installed,the weight of the car must be put back on the axle BEFORE tightening the bolts holding the center support.If this isn't done,the center support and bearing will be pre-loaded lengthwise and both pieces will fail within a few days.
Ray

[DrJ]

[ QUOTE ]
I have never played with THAT particular driveshaft,but WHY won't it let you put it "in phase"? Is there a master spline on the yoke and collar? This does have a carrier bearing,correct?

[/ QUOTE ]

It's been a long time since I had one apart (I haven't pulled this one yet, still working on the front end) but I think there was an odd number of splines so it will only go together one way and be in any phase at all.

[Travis]

I hate messing with these things too. I bit the bullet and sent mine to a shop to get it balanced. It's coming out again next month to get the rear end bagged so I need a slider driveshaft on the back half. If you take your driveshaft apart... mark it to be sure to put it back together exactly the way it came apart. That includes both driveshafts and the center yoke. And yes you do not tighten the center support bearing until after the ride height has been set. Otherwise it yanks out the bearing.

Travis

[DrJ]

Ya see, I'm lowering it and according to the book, step one is making sure the car is at correct ride height and then they have a series of angles from the engine to the front shaft and then shims at the carrier to correct that and then an angle from the front shaft to the rear shaft, that's the one that's going to be all out of wack with the car lowered obviously, and then there is an angle between the rear shaft and pinion and the upper control arm is supposed to be shimmed to change the pinion angle to get that angle.
That's the part I don't get because those are dynamics that change with every bump in the road!
If the shafts were both in phase it wouldn't matter, it would work like a constant velocity joint with the accelerations of one shaft canceling out the other.
If my tranny had a long tail shaft I'd go single piece shaft, but it's a short T350 and I don't want to change it just for that (can't afford to)


Good thing is I just found out the rear adjustable air shocks hold air! http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[1oldtimer]

i have 2 cars, 1 truck with the 2 piece and have no problems. all have a slip joint on the rear shaft. the cars were too short (about 1"), it was pulling on the center support and blowing them out quickly (6 months). i have the driveline shop put a slip joint in (like front shaft on 4x4) and cut it an 1" longer (and balance the shafts). both cars have been in there about 3 years, the truck about 6 months and going strong. if i remember correctly the yoke just past the carrier can only go on one way. i lowered my '60 elco (stock new springs- removed 2 coils) and had to remove most of the shims at the torque arm, my girls car a '61 bel air (350/350) is stock height and i left the shims. as long as you re-install it back the same way you'll be ok, worst case is you might have to balance it. make sure the angle is ok AFTER you lower it MAX 3 deg, vibrations can also be caused by to much angle.

[skyspop]

I have a question also,I have a 62 impala that I had heavier rear springs put in,it raised the assend up a bit,And had a 400 small block installed,I dont know if the driveshaft was tightened at the hanger bearing while on a hoist or not,but it does knock pretty good if I get on it from a standstill,however at easy ecceleration,no problem and I have driven it about 3000 miles so far with no shake at high speeds or any vibration other than rapid takeoff,do I need to shim it at the hearing because of the added lift in the assend?I read somewhere that the angle of the driveshaft may be too severe and knock.any help?

[1oldtimer]

is the carrier bearing still ok?

[skyspop]

As far as I can tell,I crawled (squeezed my fat assunder it)and grabbed it to see if it shakes any and seems solid..... That is if you were replying to me.Thanks,Patrick

[1oldtimer]

patrick,
it sounds like something is moving, i would see if there is any wear marks on the drive shaft (from rubbing), check the trans mount, just in case check the motor mounts also i've seen more then a few crossmembers crack around the torque arm.

[JimC]

Good Dr, are not the front yoke and front section phased together, with the second shaft phased at the differential?

[DrJ]

[ QUOTE ]
Good Dr, are not the front yoke and front section phased together, with the second shaft phased at the differential?

[/ QUOTE ]

I think the answer to your question is yes, and logic says that's wrong. and the "religious experience" of having to shim shaft angles to try and make it work tells me it's just plain wrong engineering (won't be the first time GM engineering screwed something up) since turning the odd U joint back into phase, which I realize does put the trans yoke 90º to the pinion yoke, would be the correct way.
That's the way the Volvos are and their repair books, (I have several) don't even mention ANY angles or shimming, just to make sure the drive shaft isn't bent or out of balance, and make sure the yokes are IN phase on each section. Plus, they come with the splined slip joint at the rear shaft where it belongs for the rear end motion to not affect the carrier bearing.


What I want to know is, Has anyone changed the phasing on one of these Chevy shafts, by changing the way the shaft is made, so each section is in phase with itself, like the Volvo and most every other double shaft vehicle is, and what were the results?

Does the pinion then have to be parallel to the motor?
I always thought that a properly phased double drive shaft worked like a CV joint and did away with the input and output alignment problem.

[JimC]

All that I did to my 62 was shorten it to accomodate the short shaft Turbo350*originally a powerglide car) snd replace u joints and Carrier bearing.

I have a manual for my 62 that is a compillation of copies of Cheverolet build prints.
It shows the parts, part no. and assy. sequence with angles of each segment of the propeller shaft.
It did not explain to set the carrier bearing with ride height and weight. Nor, does it mention shimming.Which I did not do.

I set mine in the frame as you see it in the picture posted above. After nearly 35,000 miles, some of them hard starts, not a groan or pop in the drive line.
I have been lucky?

[DrJ]

According to my '64 Motors repair manual, '58-'60 Ponchos had the X frame and a similar two piece shaft but it was splined behind the center support, the way CheapChevy should have. so there shouldn't be a problem with rear end altitude or movement.
It appears that the front shaft is out of phase like the Chevy but it is aligned straight with the engine tranny output by shimming the rear engine mount and/or the center support so it doesn't affect the motion in the same way the Chevy does.
I'm going to look into that design.
I bet it was copied by Inland Empire driveline for their splined Chevy shaft. http://www.iedls.com/twopiece.html
I was just noticing in the photo, they don't have the sections together but they do show them as if they go together in phase on both shafts