rear end pinion angle ?

[buds56]

I just set an 87 C-10 rear on the trailing arms with new saddles (not welded yet) on my 61 C-10.

It's a bare frame so there is no spring compression.
My thoughts are to remove the springs, bolt the shocks on and set the pinion at mid shock travel, I'm figuring 2-3 degrees up with the frame level.

I'm curious what others have done in this situation.

Final plans at this point are stock ride height.
Thanks for the help, Bud

[61 apache 10]

Pinion angle is always set to the drive shaft angle, at ride height.
The pinion is set, nose down to the drive shaft. This allows for the pinion to torque upwards under hard acceleration and NOT reach 0 or worse, a negative angle.
On trailing arms, 4-5 degrees nose down to the drive shaft is where I would set the pinion.
A U joint is designed to, and must have "some" misalignment. If there was no misalignment in the joint the drive shaft could have a tendency to whip, cause a vibration and wheel hop.
Hope this helps.

[siggyfreud]

As mentioned, everything I have read says you want to set it at ride height, under the weight of the full vehicle.

For my rear (leafs) I need to weld on new perches, that will determine the angle. So I ground paint off the rear in those spots, bolted it in with the ubolts, and will then set the angle, tack the brackets, and then pull it and weld the brackets on.

I have read somewhere around the -3 for the pinion, and the opposite at the transmission side.

[NEWFISHER]

What is your trans sitting at ( measured from the output flange)? It should be -2 to -4. I set mine with the rear within 3 degrees of the trans to avoid vibration at ride height with 400lbs in it. Mine have all been up not down.

[buds56]

Thanks for the replies.
I figured to set the trans angle when I build the crossmember and engine mounts.

I'm trying to get the frame rolling so it can be pushed in and out of the shop.

When doing this I always in the past set the pinion up when the trans yoke is higher than the rear end yoke.

I'm trying to determine a ride height with a bare frame.

I do have a chevy engine on a stand I could load the back with.

Thanks again I appreciate it, Bud

[Captainfab]

Your engine and trans should typically be 2-4* down to the rear, which means that the pinion should be 2-4* up. The trans output shaft and the pinion shaft should be as close to parallel as possible.

[PGSigns]

I would just bolt it in and not weld the pads to get it rolling. Then when you get the engine in you can set the chassis on blocks with out the springs in it to get you the ride height you want and get good measurements for setting up the pinion.
Jimmy

[TheDark1]

There's an APP for that!! LOL Tremec has an app that lets you use your phone as a level. The level on the iPhone is in "extras". Open the "Compass" and it's on the second page. -----Jeff