understanding rear pinion angle and phasing driveshaft video

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bbrroowwnn

bbrroowwnn

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This is why pinion angle is so important when setting up your rear.....Also mark the driveshaft so you get it in the same spot when you put it back together or it will be out of phase....I had people tell me it doesn't matter.....this demonstration will show you why.....You want the angle of both joints to cancel out

[ame="https://www.youtube.com/watch?v=gmV4qwLfOMY"]Drive shaft velocity - YouTube[/ame]
 
Great video. I just shimmed my rear end to get it parallel with the drivetrain. I had no idea about driveshaft phasing. Mine has been on and off so much it could be anywhere. Is there a way to check phasing?
 
Great video need to check mine as I had one cut for the Dart and didn't check or set pinion angle
 
This is one of the best videos I've ever seen on this subject

For most of you, phasing (in A bodies) will never be an issue

Phasing problems only happen when

1....on a one piece shaft, the "machinist" improperly aligned the end yokes before welding the shaft together

2.....on a shaft with a rubber inner/ outer shaft, the rubber has slipped (Like a C body)

3.....on a shaft like a replacement early shaft , converted to a slip yoke, the slip yoke spline bets rotated so the ends are out of phase

4.....and of course same as above EG 4x4 with a slip spline on the shaft.


What MIGHT be an issue is that an original shaft might have a yoke and shaft that were balanced together, and that changing U joints without marking the original orientation changes the balance. This is a different issue than phasing. Phasing is when you look down the shaft like a rifle barrel, and the two bearing caps should be in exact rotational alignment.

That is something you cannot change on a one piece shaft unless it's twisted, or was welded up wrongly to start.
 
67Dart273 said:
This is one of the best videos I've ever seen on this subject

For most of you, phasing (in A bodies) will never be an issue

Phasing problems only happen when

1....on a one piece shaft, the "machinist" improperly aligned the end yokes before welding the shaft together

2.....on a shaft with a rubber inner/ outer shaft, the rubber has slipped (Like a C body)

3.....on a shaft like a replacement early shaft , converted to a slip yoke, the slip yoke spline bets rotated so the ends are out of phase

4.....and of course same as above EG 4x4 with a slip spline on the shaft.


What MIGHT be an issue is that an original shaft might have a yoke and shaft that were balanced together, and that changing U joints without marking the original orientation changes the balance. This is a different issue than phasing. Phasing is when you look down the shaft like a rifle barrel, and the two bearing caps should be in exact rotational alignment.

That is something you cannot change on a one piece shaft unless it's twisted, or was welded up wrongly to start.
Click to expand...

Great explanation, thank you.
 
Good video, but I do have one question. When setting the angles do you recommend setting both equal with the vehicle setting or do you adjust one to compensate for acceleration?
 
93ragtop said:
Good video, but I do have one question. When setting the angles do you recommend setting both equal with the vehicle setting or do you adjust one to compensate for acceleration?
Click to expand...

Typically you set the rear pinion 3 degrees below the engine/trans angle so that when you accelerate (the pinion will rise) there will be a better alignment under load.
The angle (3 degrees) will vary depending on how weak your rear spring have become and whether you use a 4 link.
Treblig
 
Thanks for your reply. Its actually a 87 Dakota with leaf springs. I apologize for posting on this forum, but I have found so much good information on here. In short, I plan to put an explorer 8.8 rear with disc brakes under the truck. Again thanks for your reply.
 
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