Have you tried turning the DS, 180* in the pinion yoke? Invert the current cap positions to other side.
driveshaft angles
- Thread starter str12-340
- Start date
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Here's a good video. I have been told by people I trust that pinion shaft angle 2-3 degrees down (from the engine/trans shaft center line) is good for a street mopar, and 4 degrees down is good for a street/strip mopar that has the front spring section stiffened, like with clamped front leafs or caltracs. I get confused when measuring the drive shaft angles and then doing all adding and subtracting, so I got a magnetic digital angle guage from Harbor Freight. Zero the guage at the transmission output and then it will read the degrees difference at the pinion yoke. I disconnected the drive shaft to get access. In the horizontal direction, have you measured the thrust angle?
Lots of places sell axle angle shims, including Mancini, Calvert, Holley, and Summit, and as mentioned previously Dr. Diff. In fact, Cass would be the very first person I would contact if I had a vibration problem like yours. [email protected]
Measure off the bottom of the trans tail shaft housing. Whatever it is up or down u need the pinion to be -3*to -5* degrees down. So if the trans is -2* down u need the pinion angle to be at least-3* down from the trans angle. So the pinion will need to be -5* down. Kim
I've tried my friend. It just ain't sinkin in. lol
It’s not what they want to hear so it falls on deaf ears. Kim
Well, the biggest thing.....and I think you'll agree is, it's kinda like timing. Not one setting works for every vehicle. It's totally dependent on what you're doing. That said, the 5 degree nose down gets you in the ballpark real quick most times.
Thank you, this is a great idea! Now that you pointed it out, it seems obvious, but I haven't heard of it before. I have been thiinking about how to measure side angle, and this solves that problem, and it's a lot easier than measuring up/down angle at the damper than at the trans output.
Do you know an easy way to check if the pinion shaft is close to parallel to the entgine/trans center line in the side direction, or should I just have an alignment shop measure thrust angle? I have thought about comparing cross measurements from the spring locating holes to some TBD points forward in the frame.
CudaFactHackJob
Well-Known Member
He's not listening because you guys are wrong. If both front and rear yoke angles are down; you'll have a vibration unless the axle is twisted upwards in the front; under acceleration; at which time the yokes would be parallel, but just at a crusiing speed, the yokes are not parallel. Listening?
No, you're not listening or understanding, but then, no one can tell you a damn thing, because you already know it all.
plumkrazee70
Well-Known Member
@str12-340 Any updates? Did you try shimming the pinion down?
mderoy340
Well-Known Member
Make sure the driveshaft is not bent. People throw them around like 2x4s.
Also check the u joint phasing.
Also check the u joint phasing.
CudaFactHackJob
Well-Known Member
I have developed a system to cut and weld driveshafts without using a lathe. I have never had an imbalance problem or vibration from them. I've lost count of how many I've done. So, yeah, I'll comment based on what I know, not like some who comment based on what they think others know. I've studied pinion and yoke and driveshaft angles for years so that I could do my own work. If a competent shop had been available, then I wouldn't have had to learn this stuff, but after getting burned a few times you adapt.
This shows the problems when the two angles are not the same, you get vibrations. The joint speeds up and down going the full revolution on an angle so if one joint is changing speed and the other is not quite the same angle it’s a pull and push affair, vibration. Over angled joints absorb HP like crazy.
That's true, it does. What it does not show however, is how the suspension loads and changes the u joint working angles. Without that added into the equation, you cannot set the angle correctly. Every bit of this is covered in the MP chassis and suspension manual. I just don't get why some people (not you) want to say their methods are incorrect, because they are not. They're spot on.
Oldmanmopar posted up the MP section on driveshaft angles in another thread, and Still everyone had their way and disregarded the info. lol
I saw that. It's amazing how many people will claim Larry Shepard and company don't know what they're doing. LOL
Way To much info out there and a lot is wrong. Lead a horse to water but you can’t make him drink. Don’t we see this in everything today?
Purdy much, yup.
Setting Pinion Angle - Quality Body Shop Drivetrain
Pinion angle is the relationship between the transmission centerline and the pinion centerline, not to the driveshaft and not to the ground. Ideally, the pinion should become relatively parallel to the transmission as the pinion wraps up under power. This is how U-joints are designed to run...
www.doctordiff.com
This is the way I do all my cars. If there is a vibration issue, start looking at other potential areas, including DS angles to find the source.
Where would you like to start with incorrect info in some of the SA books over the years? Nobody is infallible.
33IMP
Well-Known Member
I set my ss spring car nose down 5° from the trans, bracket car on slicks. My ladder bar car, and my four link car are both 2° down. It depends on use, and suspension type what #s work best.
When you set your pinion at 5 deg. what was the angle at the crankshaft centerline?
33IMP
Well-Known Member
**** if I know. I haven't measured it yet. The 9" swap has yet to be done. Setting the pinion at 5 degrees is how I've done it for forty years and I've always been damn close.......right on the money a few times. Everybody's scared of 5 degrees initial pinion angle, but they fail to realize, that backs off a hair when you install the rear end on the leaf springs.
Most factory engines are within the 2-4 range. pinion should be set 5-7
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