Pinion angle help

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7dart0

7dart0

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I just installed my gear vendors unit and had a new driveshaft made with 1350 series ujoints. I'm getting a vibration which I assume is from my angles.

Currently my transmission is 3* down, pinion is 3* up with a driveshaft angle of 1.5*. Car is sitting level at ride height. I have SS springs and a pinion snubber.

Should I be adding a 2* shim to bring the pinion down so I can offset for pinion rise under power?
 
Yes. You dont want the pinion and the trans output to be on the same plane at rest. You want <=3 degrees down at the pinion to allow some spring wrap under load to lessen this to near 0. If your trans is 3 down already , you can have a zero pinion at rest. you want as close to zero offset as possible under acceleration.
 
Ok thank you. I'll order a couple of shims today. I'm not sure they sell 3* shims, so would you go 2* or 4*?

Tom
 
I'd have the driveshaft balance checked too. When I installed the Dana in my Dart several years ago I had a 1350 driveshaft built by a very reputable company in Michigan. The shaft was well over $400. I chased a vibration for years, nothing I tried worked. I was rebuilding my 727 and the shaft was out so I took it to a little local shop to have the balance checked. It was way out of, now it runs nice and smooth.
 
justinp61 said:
I'd have the driveshaft balance checked too. When I installed the Dana in my Dart several years ago I had a 1350 driveshaft built by a very reputable company in Michigan. The shaft was well over $400. I chased a vibration for years, nothing I tried worked. I was rebuilding my 727 and the shaft was out so I took it to a little local shop to have the balance checked. It was way out of, now it runs nice and smooth.
Click to expand...

Had my driveshaft balanced by a recommended "race shop" and it was still quite a bit out of balance.
A second look is a good suggestion.
 
TrailBeast said:
Had my driveshaft balanced by a recommended "race shop" and it was still quite a bit out of balance.
A second look is a good suggestion.
Click to expand...


I'll have to Google it but I only know of the driveline shop I used in my area. I will look into it though. It just stinks because the just made it last Tuesday and wasnt cheap at $370 for it to be out of balance
 
7dart0 said:
I'll have to Google it but I only know of the driveline shop I used in my area. I will look into it though. It just stinks because the just made it last Tuesday and wasnt cheap at $370 for it to be out of balance
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Yours may not be out, just something to check. I changed the pinion angle several times and nothing helped, so all that was left the driveshaft or the rearend.
 
Ur pinion angle needs to be 3-5 degrees below ur trans angle. If ur tranny is already down 3 u need to be at least 6 down at the pinion. The pinion raises up under acceleration. Kim
 
oldkimmer said:
Ur pinion needs to be 3 degrees less than ur trans. So trans -3. Pinion needs to be -6. Kim
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if your trans is down -3, your pinion should not be at -6! That would net you only -3 on leaf wrap up. you want 0 on wrap (under acceleration) they are facing opposite directions so you have to add the values. -3 /--------/ +3 would be net 0
-3 /--------|+0 would be -3 -3/-----------\ -3 would be -6. Factor in your snubber travel too.
 
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Try this
Setting Pinion Angle - Quality Body Shop Drivetrain
“FROM ABOVE LINK”
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.

When the vehicle is resting on its suspension, make the pinion parallel to the transmission as a base line, then tip the pinion downward 2 degrees (for a street car). This is referred to as 2 degree negative pinion angle.

As a rule of thumb, I don’t like to run more than a true 4 degree negative pinion angle.
 
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What Skidnark said ... it is important to understand what 3* pinion angle represents. It is not what the angle meter says. it is the difference between the pinion or trany and the driveshaft angle.
 
Agree with skidnark. The driveshaft with a GV is very short and working angles of the u joints is critical. I run stiff springs with a pinion snubber 1/4" from the floor at the track and pull the pin to drop the snubber on the street. I chased a vibration after the GV install and when the shop shortened the shaft the u joint phasing was off by 3*. I was pissed and chased pinion angle. My trans is 1.5 down and pinion is .5 down. Checking the u joint phasing first.
 
mbaird said:
What Skidnark said ... it is important to understand what 3* pinion angle represents. It is not what the angle meter says. it is the difference between the pinion or trany and the driveshaft angle.
Click to expand...

mderoy340 said:
Agree with skidnark. The driveshaft with a GV is very short and working angles of the u joints is critical. I run stiff springs with a pinion snubber 1/4" from the floor at the track and pull the pin to drop the snubber on the street. I chased a vibration after the GV install and when the shop shortened the shaft the u joint phasing was off by 3*. I was pissed and chased pinion angle. My trans is 1.5 down and pinion is .5 down. Checking the u joint phasing first.
Click to expand...

Those words are not mine, they are a cut and paste from the link I posted above. Sorry not my intention to mislead anyone.
 
IMO, anywhere from 0 to -1 on pinion would be fine in most every case for this one.

If the -6 is the difference, that's the high side of reasonable. If that is the pinion point down -6 relative to level, way too much.

Anymore than -4 and the U joints start to get stressed.
 
crackedback said:
IMO, anywhere from 0 to -1 on pinion would be fine in most every case for this one.

If the -6 is the difference, that's the high side of reasonable. If that is the pinion point down -6 relative to level, way too much.

Anymore than -4 and the U joints start to get stressed.
Click to expand...
Did u see his tranny is down 3? Kim
 
Yes and if trans is 3 down the pinion needs to be up 3 for parallel.

Roll it down 3-4 degrees and you are at pinion 0/level or 1 degree pointing down
 
So at rest pinion is at 0
Under power pinion rolls up to an angle inline with engine/transmission angle.
 
skidmark said:
Try this
Setting Pinion Angle - Quality Body Shop Drivetrain
“FROM ABOVE LINK”
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.

When the vehicle is resting on its suspension, make the pinion parallel to the transmission as a base line, then tip the pinion downward 2 degrees (for a street car). This is referred to as 2 degree negative pinion angle.

As a rule of thumb, I don’t like to run more than a true 4 degree negative pinion angle.
Click to expand...
ha, see post #12.
 
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