Pinion angle

[NITROUS]

Hey guys, thought I'd ask how many of you with OBS trucks had to level their motor out at the tranny? My install was a little unlevel and this could have been from the 4/5 drop. I shimmed the tranny and carrier bearing 1/2" to correct pinion angle.

[RedHeartbeat]

I never bothered to check pinion angle. Under load it's going to move anyway since I don't have ladder bars or anything to triangulate the rear end and keep it from twisting. CalTracs sound good. Maybe I can sell my spare 4L60E or 4L80E for funds.

[farmtruc]

I had to angle the rearend on mine, it was from lowering the truck though.
The rearend should be pointing slightly up, and the trans slightly down, both being parallel with each other.

allen

[motoxlifer]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; May 1 2006, 09&#58;09 AM) [snapback]51736[/snapback]</div>

I never bothered to check pinion angle. Under load it&#39;s going to move anyway [/b]

This movement is why pinion angle is critical. If your pinion angle is too high to begin with and then when you accelerate the rearends upward rotation will make the angle even more severe and could possibly break the driveline, not to mention absorb HP.

<div class='quotetop'>QUOTE(farmtruc &#064; May 1 2006, 09&#58;45 AM) [snapback]51739[/snapback]</div>

I had to angle the rearend on mine, it was from lowering the truck though.
The rearend should be pointing slightly up, and the trans slightly down, both being parallel with each other.

allen
[/b]

I didn&#39;t think you ever wanted to have a positive pinion angle unless you had a lifted 4X4 or something.

[RedHeartbeat]

Due to leaf spring twist under extreme acceleration, I&#39;ve always heard to angle it down 2-3 degree to compensate for the upward twist during acceleration, unless you have triangulated ladder bars or a 4 link. Even the old fashioned slapper bars would allow the leafs to twist.

[motoxlifer]

Well I guess you could still have a negative pinion angle with the rearend pointing slightly upwards.

[RedHeartbeat]

I&#39;ve always heard that you want the output shaft and pinion angles the same under extreme load conditions to get the most benefit. In a perfect world you would have the output shaft and pinion on the same exact centerline at all times.

[motoxlifer]

The thing that makes it confusing (to me anyway) is that you measure pinion angle in relationship to the driveline and not the ground.

[GMCwantsLS1]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; May 1 2006, 10&#58;22 AM) [snapback]51744[/snapback]</div>

Due to leaf spring twist under extreme acceleration, I&#39;ve always heard to angle it down 2-3 degree to compensate for the upward twist during acceleration, unless you have triangulate ladder bars or a 4 link. Even the old fashioned slapper bars would allow the leafs to twist.
[/b]

Mine too&#33;

[NITROUS]

I thought other members would have this problem. I tried to keep mine at negative 2-3 degrees. This will sure keep the vibration low pushing over 400 HP. Oh, and then there&#39;s the NOS&#33;