Pinion angle question, help! car on jacks now. thanks!!

[fdjizm]

Got the car up and I am so confused don't know how I go to this thinking but been searching the internet, I set my pinion angle to what I thought to be -2 but my pinion is still pointing up towards the transmissions. NOT down towards the floor. should the pinion be pointing DOWN towards the floor or just a difference of 2 degrees.

Simple question: forget about the trans its always pointing slightly down, should my pinion be UP physically (towards the sky) 2 degrees past the trans measurement or DOWN physically (towards the ground) 2 degrees past the trans measurement!?

right now it's pointing up and kind of in line but still 2 degrees from the trans measurement. I have a feeling this is not correct?

 

[BirdMan65]

Do you have a one piece driveshaft?

 

[fdjizm]

Yes 3.5" aluminum.

 

[BirdMan65]

Adjust the pinion angle down from an imaginary line down the center of the driveshaft, irregardless of the angle of the transmission.

If the driveshaft is uphill from the diff at 4* then the diff is uphill at 2* then the difference is 2* pinion angle. It is basically a very shallow V.

 

[fdjizm]

I know I can have a difference of 2* both ways though, with the pinion facing up or the pinion facing down.

So you're saying it should be facing down from the measurement of whatever degree the trans is down?

Right now the trans is pointing down (to the ground) 4*
If I put the pinion down 2* from that 4* it is still physically pointing upwards... is that correct?

 

[BirdMan65]

The driveshaft, not the trans!!

Yes, the nose of the diff can be pointed up from ground level as long as there is a 2* angle difference to the driveshaft.

 

[Rob72]

I imagine a truck with a lift kit. The pinion is pointed up on a close plane with the DS even though the trans is level.

 

[dysan]

The car needs to be on 4 ramps, blocks, etc...needs to be 4 of the same height things under you tires to properly adjust the pinion angle.

As for the angle of the pinion flange, I would suspect you do want the pinion flange pointing down since when you launch it will raise up. I don't remember what my angles were but my pinion flange was pointing down towards the floor and I think my trans was nearly level. I set mine up around 2.5* difference.

 

[fdjizm]

I spoke to Dustin (CPRsm) on the phone, he explained it to me! thanks a whole hell of a lot man!!
Dysan yes that is the idea, I was confused because my pinion nose is down 2* from the trans shaft and it still faces up just a bit.
But Dustin assured me that it's 2 degrees DOWN FROM the trans shaft whether it looks to me like it's facing down doesn't matter it can face up slightly and still be correct.

So right now my trans is 4* down and my pinion nose is 1* up.
Which is 3 degrees down from the trans measurement = -3* so I should be good with that! (rubber bushing still on upper diff housing)
Dustin said I will be good with -3 so there I am! thanks again homie!

what a mind fuck! I actually was correct how I had it but just thought in my head that it should face down, but it doesn't HAVE face down.

/meltdown

edit: Dustin!!!!!

 

[stkjock]

http://www.cherod.com/mustang/HowTo/LCA _adj.htm

http://www.cherod.com/mustang/HowTo/DriveShaft/driveshaft.html

 

[fdjizm]

http://www.cherod.com/mustang/HowTo/LCA _adj.htm

http://www.cherod.com/mustang/HowTo/DriveShaft/driveshaft.html

read all that man, was still confused by this...

"making the nose rear end housing dip down a little bit. Go about 2 degrees beyond the trans flange measurement."

My pinion rear end was not pointed down towards the ground and still isn't, thats why I was confused. I thought it HAD to point down towards the ground.

 

[cm581978]

My mind is going to explode after reading your post Frankie lol

 

[fdjizm]

You weren't the one under your car screaming "FUCK IS THIS RIGHT!??"

 

[fdjizm]

Thought it would be cool to get a vid on the pinion rotation so I could see how the PA changes under acceleration if anybody wanted to check it out... I had the line lock on cam on the floor.



Looks like it moves up 3-4 degrees or so... so I guess since I am at -3 it would be nice and inline with the trans on launch.

 

[Makdaddy]

Frankie this is the way I understand it
Off of the Horizontal plane anything pointing down ( Pinion) (Trans Flange) will give a negative reading anything pointing up is a positive reading.
So you add the 2 readings together
I:E
Trans Flange -2 and pinion -4 added will = -6
So to get to -2 or -3
Trans flange stays at -2 the pinion is adjusted to -1 this will give you -3
take the pinion to zero and you get -2
I measure Trans and pinion with a carpenter square, mainly so I can get the inclinometer low enough that I can read it accurately.
In fact the last time I did mine the pinion is pointing a little down and read -4. and my tranny was -2
I couldt get my wrench into it with the suspension loaded, I need to get it on 2 post lift and drop the suspension and get to the UCA to adjust
But I will take 4 degrees upwards to get to my -2

And yes this shit can make your head expolde

 

[Rob72]

I'm having a hard time following the logic of all this. Taking an angle measurement of the trans seems only relevant if the trans and pinion flanges are on the same exact plane. As I've previously said a truck with a lift kit has a relatively continuous line between the driveshaft and the pinion with the driveshaft sloping down from the trans. That to me seems to put the least amount of stress on all three components.

 

[fdjizm]

All I know now and from speaking with Dustin, is that whatever my trans flange angle is... set my pinion angle my desired degrees DOWN from that (shortening the UCA) But the pinion doesn't have to be physically facing the ground.

I have also read that if you aim the pinion right at the trans flange the U joints are not "working" whatever that means, also if you accelerate hard the pinion goes up even more and causes binding.

So you want to compensate for what the pinion is going to do upon acceleration.

 

[BMR Tech]

 

[Rob72]

I understand that Kelly. What I don't understand is when you are changing the stock ride height and I use a truck with a lift kit as an example because of the extreme modification on the suspension the pinion is angled up to be closer inline to the DS. That seems to me to minimize the angle and stress on both u-joints. I would think that with a car that principle would still be used?

 

[Makdaddy]

This is close but uses a two piece drive shaft

Notice he talks about the rear pinion pointing up and the reading is a positive reading