2.5 degrees UP from level.

Your tailshaft is DOWN 3-3.5 from level. If this is true it puts them close to the same plane.

This is exaggerated: Tailshaft: \ Driveshaft: / Rear: \

i just dont see his driveshaft going up from the trans to the rear diff. My car is Low and i know its a 1st gen but i still have 1 degree down on my driveshaft angle. If his driveshaft is going up my guess is that he is measuring his engine angle wrong. The crank pulley and fuel rails were the easiest spot for me to measure.

Trey, make sure whatever you are using for an angle finder is EXACTLY straight front to back for each measurement. It being just a bit off skew can really mess with the numbers.

And run to harbor freight and get a digital gauge if you don't have one already. The needle gauges are way inaccurate in my opinion.

Thank you. That's what I've been thinking and saying but the number of articles and information pages I'm reading that say the pinion angle is the difference between the drive shaft angle and the angle the pinion is placed at is staggering and it pisses me off, lol. It's just confusing me because in my mind the difference between the angles is the working angle not the pinion angle. Just wanting to make sure I'm communicating properly.

I measured at the balancer just a minute ago and it's showing 2.5 to 3 degrees up from level which causes the tail shaft to point down. I think I'm going to invest in a digital angle gauge so I can stop expecting this manual gravity one to be accurate. It's hard to read as well.

If you stand on the driver's side of the car moving from front to back, my drive line looks like what Todd posted \ / \ .

Thanks everyone

The face of the U Joint is the best place to measure all the angles. I used a socket and angle finder, but a magnetic finder would be much easier as you could stick it right on the u joint.

that makes no sense. the engine cant be angled up and the trans pointing down at the same time.

I have this one
https://www.amazon.com/Floureon-Incl...l+angle+finder

Why not, Randy? The balancer is in front of the engine mounts which are a pivot point and the transmission is after the mounts. The tail shaft is slanted down at the rear and the balancer is slanted upwards.

Lance, your reply came in just before mine. I agree with the tilt of the gravity angle gauge. I always work to make sure I'm pointed straight down so that the pendulum swings and doesn't get pinned. There's an HF down the road. I'll swing by tomorrow I think.

I appreciate the replies. I was out of town all weekend so I haven't touched the car. Hope to get back on it soon.

Thanks

The yoke is on the same plain as the crank shaft balancer. The engine if angled up the trans yoke is angled up. All of this is being over complicated.

Get the engine or tail shaft angle
Driveshaft angle
Rear pinion angle

And then you will have all the front and rear operating angles that you need.

Trey ---


One of the things that gets messed up is trying to make it too complicated....


And remember that you want the PINION angle DOWN -- because as the power is put to the rear end - it tries to rotate the pinion UPWARDS.... The type of suspension you have makes a difference in how much this is allowed to rotate from a "negative" to the positive. A race suspension which allows hardly any movement -- should be set about 1 to 1.5* Down (at the pinion).... and a rubber suspension would be 3.5 to 4* down - because it's going to rotate up A LOT.... Urethane bushings would be "harder" and can be set at 2 to 2.5* Down etc.

So you need to know the suspension set up and adjust accordingly.

The motor is going to be 3 ish * down at the tranny ----- and the diff should be set according to the appropriate down angle (allowing for it to climb back to about zero in hard launch mode) according to how much movement it should have (a little - moderate - or a lot) -- and the working angle of the driveline will mathematically work out to about 1 ish * (the angles should cancel each other out, but they should never be 0 ----- is should always have 1 to as much as 2 degrees "difference".

So let's say the engine is down 3* -- and the driveline is down from the motor to the rear end 4* -- and the pinion is down 2*

Use this calculator to help when you're measuring



http://spicerparts.com/calculators/d...gle-calculator

This is why communicating properly is important and why I wanted to make sure we all understood each other. We're saying the same thing but we're looking at it differently.

To clarify, when I say the pinion is pointed 2.5 degrees up, I mean the nose is pointed up. The gear is pointed down. Using the link/calculator Greg posted, they consider the pinion to be sloped down.

Thanks for the link Greg. You're correct about over complicating it. What you've just posted is what I've always thought and worked towards. Until I started having problems that is. Then, I decided to learn more and ended up where I am now. :knokwood:

Luckily, I have 6* of angle shims under the rear so tilting the pinion nose down won't be hard. I'm going to remove the snubber/bumper on top of the transmission too so I can lift it a little more. We'll see where I can get the angles to go to from there.

Thank you all.

I went out and bought a digital angle gauge from Harbor Freight today. I verified it against a bubble level and my gravity gauge. I'm confident it's accurate within a couple tenths.

Pinion is 3 degrees nose up. Drive shaft is 1.5 degrees rear end up. Tail shaft is 3 degrees down.

Numbers are a little better I'd say but still not good enough if working angles are to be below 3 degrees.

I'm not sure why the drive shaft angle is less with the digital gauge. I put the gravity gauge right next to it and it went right back to the 3 degrees I measured the first time. I'm going with 1.5 degrees.

I'll adjust the angles in the coming days and see what happens.

Thanks

So driveshaft and pinion is in a /\?

If so dropping the rear pinion to neg 2 degrees should lower the driveshaft to closer to zero and maybe plus or minus .5 degree. If the driveshaft does go to a neg .5 them your front operating angle would be 2.5 and if rear pinion down neg 2 degrees it would make the rear operating angle 2.5 as well. Both operating angles would be equal if thafs the case

Correct. The drive shaft to pinion looks like /\.

I'm hoping to both raise the transmission and lower the pinion, but we'll see what I can come up with.

Thanks Randy

I lowered the pinion last weekend to the point that it's about .5 degrees nose down now. This got the working angle at the rear u-joint down to around 1.5 degrees. I was still slightly up in the rear. This did change the front working angle but it was still a little over 3 degrees. I took the car out for a drive anyway. Nothing changed or it changed so slightly it's not worth mentioning.

Today, I tried to raise the transmission by removing the snubber on top to gain the clearance I needed. I wasn't able to go up but a few tenths due to the reverse lockout hitting the tunnel now.

So my plan at this point is to cut the tunnel out enough to get the transmission where I need it. I'll leave it open until I'm certain I have the transmission where it needs to be. Hopefully, this will either fix the issue or allow me to rule it out.

Some maybe good news is I think I'll have the clearance I need for the headers though it will get tight in places once I raise the engine. I'm also fairly certain I won't have to raise the tunnel over the driveshaft. I'll just have to change the tunnel over the transmission.

The bad news and why I'm going to leave the tunnel open until I'm certain the angles are correct is that I'm going to have to cut out part of the factory tunnel brace that's spot welded to the floor from side to side. The drive shaft will be way too close if it clears at all once I raise the transmission. This means making a DSE style trans brace and putting in new floors which I needed anyway. I'm not willing to do all of that until after I know the drive line angles are working correctly.

We'll see what happens. I'll be back with an update later.

Might not be an issue -- but if you have a rear sump -- don't get that up so much that the oil doesn't flow in to it..... ??? Maybe the pan is already sloped enough that it doesn't matter - I don't even know what motor you're running etc.

That's a good point, Greg. I'll check it soon to make sure I'm ok. The engine is still a Gen II LT1 though it is stroked. Thanks.

Finally! After all this time playing with this damn vibration issue, I have affected it with an adjustment. It's not fixed. It's better in some ways and worse in others, but it's in the drive line for sure. Hopefully, it's only the drive line and I don't still have multiple issues. I'll play with it more this afternoon and see what happens.

Thanks!

Well ------ at least you're on to the cause. That's 90% of the battle.


Watch this video....
download this handy dandy phone app...... LOL it might help make setup easier.

Good news Trey! Interested in what you’ve found.

Thanks Greg. I'll take a look.

I raised the transmission up, Scott. Too much working angle in the front u-joint I do believe was the issue. At least that's what I was adjusting anyway.

Later in the afternoon I raised the nose of the pinion back up just a touch to see if that helps make things better as I had it about .5 degrees nose down. I haven't taken another official measurement but I should have the pinion .5-1 degree up now and the transmission 1.5 degrees down. The weather sucks today so I may not get it out to see if that helped make things even better.

Trans tunnel will eventually have to be removed entirely. I did that wrong way back in 09 when I first did the swap. I have the Hooker T56 tunnel piece coming. We'll see how that fits before I cut any more. If this works, I'm still confident I won't have to raise the driveshaft tunnel, but the factory brace in the floor I mentioned early does have to be cut for me to be happy with its clearance. It's really tight right now.

Well, the rain moved out early and the roads dried out enough that I could get the car out. It's even better than before so I'm getting closer. If this is the best it gets, I could live with it consider how bad it was before. I do still have some adjustments to make. I need to get it back up on the cribbing so I can get an official measurement to know where I am. The biggest issue I'm facing now is the car has a shudder that runs through it as I coast down from speed. Fairly certain this is pinion angle related for sure since I don't feel it going up through speed or while driving. I'll continue to do research and see where it leads.

Thanks for all the help everyone.

If you have vibration while deceleration the pinion might be down to far. Glad you are moving in the right direction. That aluminum driveshaft will help ALOT to get every bit of vibration gone

Trey, how is this going? We’ve had a day or two without rain, so I know you’ve driven the car some.

Thanks for checking, Scott. I actually haven't touched the car. I'm also working on my friend's 69 mustang trying to get things done on it. I'll get back on the TA soon.

So I think I may have fixed the vibration today. I lifted the rear of the trans about half a degree and that seemed to do it. Not sure why as the last time I made an adjustment I had all my angles within spec when I measured without the driveshaft in place. I think the difference may be that I measured with the driveshaft in place this time and that showed that I was a little off from what I measured before. I would have though the measurements with the driveshaft removed would be more accurate since it allowed me access to the tailshaft.

Anyway, I'm going to work on closing the tunnel in now. I'll have to make a new transmission cross brace because the exhaust is almost pinned against it now. No big deal as I have to replace the floor boards too so it'll work out.

Great to hear trey!!!!

Thanks! How the hell did you see this post so fast, lol?

when did the vibrations come on?
mine has vibrations, but only above 85 on the open highway, doesn't do it on the track or auto-x (no harmonics i'm guessing)

Score!

Great news sir!
When is the next caffeine and octane? You haven’t moved yet have you?

Next C&O is July 1, Scott.

Only moving I've done is from Sandy Springs to Dunwoody because I bought a house back in October of last year.

I haven't really done anything more with the car as I've been in Germany for 10 days. I leave on Tuesday for Tacoma, too. Doubt I'll do anything this weekend, but we will see.

Thanks!