Author Topic: Another pinion angle question (Read 2452 times)

thedodgeboys · « **on:** June 10, 2014 - 07:02:38 PM »

If the transmission is 5 degrees down and the pinion angle is 0 and the drive shaft is o degrees when installed (the trans is lower than the rear end so it travels up slightly)

Do I shim the rear end 3(or more) degrees to allow for travel to make it close to 5 degrees under hard acceleration and highway speeds?

Thanks I have read so much on this Im lost...

ToxicWolf · « **Reply #1 on:** June 10, 2014 - 07:12:39 PM »

just watching this one. I'm getting ready to drop a hemi in mine and this question has always confused me.

johns cuda shop · « **Reply #2 on:** June 10, 2014 - 07:56:18 PM »

Hey Scott, Yeah it can be confusing ,I have been down this road a few times.On a leaf spring car your pinion angle should be 3 neg of your driveline angle. If you drive line angle is set at 5 deg down than your pinion angle should be 2 deg nose up, for the reason being under load would take up the 3 deg. The height of your rear end to the tranny shouldn't matter as long as the angles are correct and the suspension is set at ride height. If its a 4 link car,its different, since the lower link arms are solid and dont move like the leaf spring does under load, both the driveline angle and pinion angle should be the same angle respectively, say 5 deg down then the rear should be 5 degrees nose up,but Im sure factory set most cars driveline angle at 3 degrees down , 5 degrees down seems excessive ,that might be why you think the rear is higher than the tranny plus you dont want your exhaust to point down at the pavment ect ect.

Katfish · « **Reply #3 on:** June 10, 2014 - 08:41:19 PM »

http://www.moparts.org/Tech/Archive/rearsusp/13.html

Racer57 · « **Reply #4 on:** June 10, 2014 - 08:47:52 PM »

I would like to know the best way to check the angles.

thedodgeboys · « **Reply #5 on:** June 10, 2014 - 10:15:39 PM »

Thanks everyone

dodj · « **Reply #6 on:** June 11, 2014 - 12:50:09 PM »

5* down is a little excessive for the engine/tranny (does it have to be like that with the 392?). At least on the stock configuration it was more like 3-4* and there were shims between the trans mount and tranny where you could raise the o/p of the tranny. Which, if I understand what you said properly, would help with your rear end angle.

Quote from: Racer57 on June 10, 2014 - 08:47:52 PM

I would like to know the best way to check the angles.

I used my ipod and the Clinometer app. Cost 50 cents. Just remember you are measuring angles in relation to the other driveline components, not the ground.

Racer57 · « **Reply #7 on:** June 11, 2014 - 01:13:08 PM »

Quote from: dodj on June 11, 2014 - 12:50:09 PM

5* down is a little excessive for the engine/tranny (does it have to be like that with the 392?). At least on the stock configuration it was more like 3-4* and there were shims between the trans mount and tranny where you could raise the o/p of the tranny. Which, if I understand what you said properly, would help with your rear end angle.
I used my ipod and the Clinometer app. Cost 50 cents. Just remember you are measuring angles in relation to the other driveline components, not the ground.

Is it placed on the tranny side and rear end side of the U-joints along with the driveshaft itself ?

thedodgeboys · « **Reply #8 on:** June 11, 2014 - 02:43:22 PM »

Quote from: dodj on June 11, 2014 - 12:50:09 PM

5* down is a little excessive for the engine/tranny (does it have to be like that with the 392?). At least on the stock configuration it was more like 3-4* and there were shims between the trans mount and tranny where you could raise the o/p of the tranny. Which, if I understand what you said properly, would help with your rear end angle.
I used my ipod and the Clinometer app. Cost 50 cents. Just remember you are measuring angles in relation to the other driveline components, not the ground.

It does sound excessive the t56 magnum is a big transmission however...

But I don't know I'm going to put it back on the ground recheck everything including my angle finder and start over.

Sometimes you just get lost and have to do that, or at least I do...pinion angle shave always confused me.

dodj · « **Reply #9 on:** June 11, 2014 - 09:51:47 PM »

Quote from: thedodgeboys on June 11, 2014 - 02:43:22 PM

.pinion angle shave always confused me.

It's a difficult one to get your head wrapped around.
You should end up with the rear about 3* nose down "IN RELATION TO THE DRIVE SHAFT", which is the same thing John's cuda shop was saying, but in a different way. It needs to be nose down in relation to the d-shaft cuz the rear will wrap upwards on accel.

thedodgeboys · « **Reply #10 on:** June 15, 2014 - 11:09:09 PM »

Quote from: dodj on June 11, 2014 - 09:51:47 PM

It's a difficult one to get your head wrapped around.
You should end up with the rear about 3* nose down "IN RELATION TO THE DRIVE SHAFT", which is the same thing John's cuda shop was saying, but in a different way. It needs to be nose down in relation to the d-shaft cuz the rear will wrap upwards on accel.

So if my drive shaft is 0 I shim the rear end 3* down?

I think I'm going to see what I need to do to raise my tail shaft up a little more and if I can I'll be at a better starting point.

bigblue73 · « **Reply #11 on:** June 24, 2014 - 09:15:25 AM »

Down load the Tremec angle finder app on your smart phone. It'll walk you through the steps. It's a pretty cool program.

dodj · « **Reply #12 on:** June 24, 2014 - 09:49:12 AM »

Quote from: thedodgeboys on June 15, 2014 - 11:09:09 PM

So if my drive shaft is 0 I shim the rear end 3* down?

Yes sort of. When you start shiming the rear, that starts changing the d-shaft angle as well, so 1.5* may accomplish what you need to do.

Quote from: thedodgeboys on June 15, 2014 - 11:09:09 PM

I think I'm going to see what I need to do to raise my tail shaft up a little more and if I can I'll be at a better starting point.

Raising the o/p of the tranny will start to give you more of a nose down relationship for the rear/d-shaft angle.

I like to measure rear end and tranny angles off of the yoke if possible. I took my d-shaft off a few times when I was screwing around with angles.

thedodgeboys · « **Reply #13 on:** June 24, 2014 - 06:48:18 PM »

Quote from: dodj on June 24, 2014 - 09:49:12 AM

I like to measure rear end and tranny angles off of the yoke if possible. I took my d-shaft off a few times when I was screwing around with angles.

interesting, from the yoke ujoint mounting serface or between the mounts in the cross shaft area?

ill post some pictures soon

johns cuda shop · « **Reply #14 on:** June 24, 2014 - 09:26:27 PM »

With the weight of the car on all 4 tires ,Measure your driveline angle off the harmonic balancer and idealy off the mounting pads yoke (but you can use the pad on the top where the pinion snubber bolts to. There should be a neg 3 degree pinion angle from your driveline angle . Here is some good info here http://www.iedls.com/Education-Zone.asp?CID=3

Author Topic: Another pinion angle question (Read 2452 times)

thedodgeboys

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