Thread: 53 Is back from the Body Shop

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I know your supposed to have the same angle on both ends. Sounds like you've had it out a few times so clocking it different has already been done. Did they have a really high quality machine for the tire balancing, I know the methods and machines are not all equal. Sometimes tires can have a bad belt that makes for a vibration, do you have any other wheels you can try?

I'll need to refresh my memory but I do not think they should both be down angles. 1 up and 1 down and within a degree with the suspension loaded.
But that's my memory talking!
Under edit - is the driveshaft "In Phase"?

More editing - maybe this will be helpful? https://www.youtube.com/watch?v=Idk3BVDVHq4 driveshaft phase video

even more editing. LOL.. another video that may help. https://www.youtube.com/watch?v=YgNZfIR-8Ng You may find the double cardan joint info interesting.

Seth,
You only need two measurements, the transmission outlet and the differential pinion and they need to be very close to equal but opposite - tranny sloping down toward the back, and differential pinion sloping up toward the tranny. Basically, if you project a line through the transmission main shaft towards the back, and a second line through the differential inlet yoke towards the front those two lines will be parallel. Ideally the two angles will be less than about 3 degrees.

What Roger said.

To expand a bit, depending on who you talk to a lot of guys will run the pinion angle on the differential down 1-2 degrees. The reason for this is, especially under acceleration, the pinion gear will tend to try to walk up the ring gear raising the pinion slightly. Supposedly even just cruising the pinion will raise a little bit.

Normally when I set pinion angle I shoot for 1 to 1 1/2 degrees down on the differential for a street car.

As far as the offset to the side it should not be a problem as long as the center line of the differential pinion and the center line of the transmission are parallel. If pone or the other is twisted a little it can set up vibrations.



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The offset of the 8.8 was one thing that bothered me on the 40 when I had one in it. But, on the other hand, I have seen many, many, over the road semis and straight trucks where the pinion was off set and the drive shaft wasn't perfectly straight and they run for hundreds of thousands of miles to millions and I've always found it odd but they work. I've ran pulling trucks at 6* up before on the street for a long time and they never developed any vibrations. My Camaro has a vibration at about 70-73. It has done it since I put it together. I am beginning to wonder if it is my thrust bushing on my tail shaft of my trans. Everything I have tried to remedy it has really done nothing noticeable. Is your 4L60E a slip yoke out put?

Ford (and others) did the offset pinion to keep the needle bearings in the u-joint cup turning so they share the wear & loading. It was found to be a problem when the bearings stayed in one place, they would cut into the journal and self destruct.

I'm starting to think I'm barking up the wrong tree and something else is the problem. The engine to 3.5 down so I put the pinion at 3.5 up and it was noticably terrible in the back. The yoke coming out of the trans was nearly straight and yoke on the rear end was way crooked and I put the Tremec angle app on there and it gave me all kinds of red flags. So then I thought maybe I need to do more math. I took the motor deg and subtracted the drive shaft angle and matched the rear end to that angle and nope, same vibration. If I put the transmission in neutral when the vibration is going on, nothing changes , at least I don't think it does, but I'm doing 80 MPH runs on a black top looking for cops so these are not long-term tests lol. I think it may be a little bit worse tonight, and I have the rear end pointing down more. I'm thinking about giving up on measurements and just angling it little bits at a time and driving it everyday to see if it gets better or worse. Maybe there is just that much driveline transfer from the frame to the cab, I don't know.

Ryan, it is a slip yoke output, I was checking that out tonight, it's maybe a little loose, I'm not sure how to tight their supposed to be.

Mine is a little loose too. My vibration I swore was the LH front tire. I put new tires on it and same little vibration. I put pinion shims on top of the springs to raise it a little and like you no change. I tried lowering the angle and it didn't like it at all. I just chalked it up to a worn trans and I'll live with it. It's not a bad vibration but it is just annoying.

Mike, I got sent to a spicer class years ago and they flat out stated that a u joint with a zero operating angle will fail faster than one that doesn't get greased regularly. I found that very surprising but they obviously know what they're doing.

"...... I am beginning to wonder if it is my thrust bushing on my tail shaft of my trans.....


Ryans comment triggered a memory for me. My 57 Plymouth always had a drive line vibration above 75 MPH, not horrible but noticeable.. When I was getting it ready to drive back to Illinois a few years ago I decided to address it........figured it was an out of balance drive shaft (it was an unmodified factory drive shaft from some MOPAR). The 57 Plymouth had 4.10 gears and an OD 4 speed so the drive shaft is spinning pretty good at 75 MPH).

Anyway when I went to pull the driveshaft I noticed a slight leak at the tail tail shaft seal and the the yolk had noticeable play. Put a new tail shaft bushing, new yolk and seal and the vibration was gone.

Not saying that's your problem, but it might be something to look at.


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It's kind of interesting how yours, Ryan's and my vibration all start at about mid 70's mph. And like yours and Ryan's, it's not terrible it's just noticeable and it bothers me. According to every video I have watched, it has been set up dead nuts on, but I cannot get my motor below a 3.5 angle without major work. I noticed my tail shaft has slight sleeping as well, I think that's going to be my next step.

Originally Posted by 53Chevy5

The yoke coming out of the trans was nearly straight and yoke on the rear end was way crooked and I put the Tremec angle app on there and it gave me all kinds of red flags.

I'm probably being dense, but I don't understand what you mean by the yoke on the rear end being "...way crooked". Are you saying that the yokes welded to the driveshaft that hold the universal joints are not aligned in the same plane? There's a lot of info out there on phasing u-joints and proper angles. Here's one from Belden - https://www.beldenuniversal.com/know...-joint-phasing
If your driveshaft yokes aren't in phase that could be your problem, but Mike P's idea of the tranny tailshaft is also a great idea to check.

Originally Posted by rspears

I'm probably being dense, but I don't understand what you mean by the yoke on the rear end being "...way crooked". Are you saying that the yokes welded to the driveshaft that hold the universal joints are not aligned in the same plane?

I was trying to say that the front yoke angle was fairly straight and the rear had a pretty sharp angle.

I never have done anything to the rear end on the camaro aside from change the fluid, put axle seals in it, and tried to put a drop in posi in it. It is a weird first year 8.2/8.5 so the lunch box posi wouldn't fit. I've always planned to rebuild the rear end and see if it was the vibration. I'm guessing no. I should have the drive shaft balance checked too but ya know, that's hard to do when it's your daily.

Roger what I meant by "way crooked" is usually seen when the car has had a major engine swap involving building new mounts and etc to get the engine in (Like the Caddy Motor in the El Camino or the HEMI in the 37.....or the V8 in a 53 Chevy). If the swap is poorly done the engine can end up being cocked in the engine compartment where the center-line of the transmission output shaft is not parallel to the to the center-line of the rear end pinion.

The other time it can happen is if the (RWD) vehicle has been hit hard in the side and then repaired. The body looks when done
but the frame/uni-body is out of kilter resulting the the center-lines not being parallel.

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Originally Posted by Mike P

Roger what I meant by "way crooked" is usually seen when the car has had a major engine swap involving building new mounts and etc to get the engine in (Like the Caddy Motor in the El Camino or the HEMI in the 37.....or the V8 in a 53 Chevy). If the swap is poorly done the engine can end up being cocked in the engine compartment where the center-line of the transmission output shaft is not parallel to the to the center-line of the rear end pinion.

The other time it can happen is if the (RWD) vehicle has been hit hard in the side and then repaired. The body looks when done
but the frame/uni-body is out of kilter resulting the the center-lines not being parallel.

Yeah Mike P, I understood what you were saying. My question was Seth saying his front yoke was straight, but the rear was "...way crooked" which still doesn't make sense to me even after his explanation. With the vehicle on level ground if the engine/tranny slope is 3.5 degrees down, and the pinion angle is 3.5 degrees up then the yoke on the tranny shaft will be straight with the tranny, the yoke on the pinion will be straight with the pinion gear shaft, and the u-joint angles (angle of fixed yokes to driveshaft) will be equal front and back. I'm just not understanding his wording.