Help with driveline angles...

[ChadW]

I have a 66 that i am building that is on air and will lay out on its frame...I just got my 2 piece driveline with a rear slip joint and aluminum carrier bearing from Performance Drivelines in Bakersfield Cali...

I have it all installed now and need some help with the drive line angles. Here is where it is right now.

Trans is 4.2 degrees down
First shaft is 0.17 degrees up
Rear shaft is 2.64 degrees up
Pinion is pointing up 2 degrees ( but i think they call this a down angles when figuring driveline angles...

The perches are not welded to the axle tubes so i can make adjustments there with no issue...I have a spacer under the carrier raising it up as well...

I have never setup a 2 piece driveshaft so am asking for help/opinions on the angles that i posted above..

Tks

[SCOTI]

When you list the trans angle as 'down' & the shaft angles as 'up', are you stating they are opposite of each other:

Front of trans is higher than the tailshaft = down
Front of 1st shaft is lower than the rear of the shaft = up

Is the pinion centerline higher or lower than the trans output @ ride height?

[mongocanfly]

Here is a good link to 2pc driveshaft setup...scroll down to 2pc...https://www.4crawler.com/4x4/CheapTr....shtml#2-Piece
Also if you can get some pics or draw out what you have itll be easier to visualize what you have

[SCOTI]

The above link is good information but it's not apples-to-apples specific when discussing trucks that can lay frame. The info linked works as stated when/where the differential is below the trans output shaft.

[ChadW]

Originally Posted by SCOTI

When you list the trans angle as 'down' & the shaft angles as 'up', are you stating they are opposite of each other:

Front of trans is higher than the tailshaft = down
Front of 1st shaft is lower than the rear of the shaft = up

Is the pinion centerline higher or lower than the trans output @ ride height?

Yes..you are correct..

Pinion center line is Higher than the trans output shaft at ride height..

i did receive an message back from Nate at porterbuilt and we adjusted my pinion to 0 and he says that all are good now...Im just trying to figure out exactly what that means...lol

trans is 4.0 down
1st shaft is 0.31 UP
second shaft is 2.26 UP
Pinion is 0

Tks

[SCOTI]

Originally Posted by ChadW

Yes..you are correct..

Pinion center line is Higher than the trans output shaft at ride height..

i did receive an message back from Nate at porterbuilt and we adjusted my pinion to 0 and he says that all are good now...Im just trying to figure out exactly what that means...lol

trans is 4.0 down
1st shaft is 0.31 UP
second shaft is 2.26 UP
Pinion is 0

Tks

Nate & I have had multiple discussions about these "severe" set-ups. I would start where you're at & see how things work. Give yourself room for adjustment & the possible addition of the double-cardan style joint set-up if needed if you can't get things vibration free.

[ChadW]

Originally Posted by SCOTI

Nate & I have had multiple discussions about these "severe" set-ups. I would start where you're at & see how things work. Give yourself room for adjustment & the possible addition of the double-cardan style joint set-up if needed if you can't get things vibration free.

when i sent him my numbers, what is he looking for? the last numbers i sent him he said "boom, nailed it" ..lol.. just trying to get an understanding of it..

[mongocanfly]

(" it's not apples-to-apples ")
True.....
I've got about 25-30 sites saved that relate to suspension setup and driveline angles..it can get confusing sometimes

[SCOTI]

Originally Posted by mongocanfly

(" it's not apples-to-apples ")
True.....
I've got about 25-30 sites saved that relate to suspension setup and driveline angles..it can get confusing sometimes

Exactly. The thing is, it's correct info for that application.

The most common phrase I've heard for the DIY builder is "match the angle of the pinion to the trans but opposite & be within a degree vs. exactly matching". They'll say 3° down @ the trans tailshaft (industry standard) & 2.5° up @ the pinion. The angles are .5° from being equal-but-opposite. The end result is a working angle of less that 1°. It might work for may apps, but not so much for extreme dropped cars/trucks. The 2.5° 'up' angle is subtracted from the 3° 'down' angle because it's below parallel @ the point of measurement for each. If the pinion is above that parallel point, the numbers are ADDED together which results in a 5.5° working angle.

What about an extreme drop application that has a ride height of about 5" off the ground??
The trans output shaft is just above the bottom of the frame rail (lets say @ 7.5").
The vehicle is using a 28-30" tall rear tire OD.... that puts the C/L of the differential @ around 14-15" above the ground.

So if the trans is pointing down & is @ approx 7.5" off the ground AND the rear pinion is approx. 15" off the ground (30/2 = 15; 15-7.5 = 7.5" slope). So it's a 7.5" slope over X-amount of inches running uphill (length of the combined shafts) from the trans to the differential. The scenario w/the trans output-to- main shaft angle getting added together typically equals a BIG working angle which is hard on joints. This is one reason why 2pc set-ups can be used to an advantage (more opportunities to minimize the angles). Most of these apps will have the pinion @ zero or slightly pointing down (more likely).

When I would explain my set-up, the usual response: "you need to raise the vehicle or raise the drivetrain within the vehicle".

[youngrodder]

Great timing for this tread. I too am trying to get my drive line angles set on my Porterbuilt set up (53 Suburban). I just sent Nate a pic and my numbers of my set up to see what he says.

Marc