Hot Rods Driveshafts and Pinion Angle Problems

Hello I am a new member and although cars are not new to me..The 32 5 window I currently have is.I know all the world needs is another Milner clone but that is what the car is. This car was a crappy build and an ebay purchase and I was totally ripped off. My fault for taking someone's word. But living on the east coast and the car was on the west made a problem for inspection. I have read the posts over and over about pinion angles. Here's my problem. When I first purchased the car back in Feb. There was a loud knocking sound from the driveshaft whenever the car was coasting at lower speeds. It has an 8" Ford rear end in it and I thought there was an issue with the gears..I replaced the whole 3rd member with a rebuilt unit from a reputable source while I was there I also replaced the axle bearings and seals. That did nothing for the issue...It has a rebuilt non WC T5...After further investigation I found the rear axle to be pointing downward a full -12 degrees..I don't weld so I had a local shop to cut the housing loose from the traction bars and set the proper angle...When I got the car back it still is sitting at -5. I am unable to move the transmission from it's current position. I have no one local who can do the job over so I am wondering if this variance it's going to be a large issue or is there a custom drive shaft option either double cardan or velocity...The current measurements are as follows Transmission is Negative -2.3 Drive Shaft Negative -2.0 Rear Axle is Negative -5.4
I have worked on this car every day since Febuary and I am still unable to make a trouble free drive. Thank You in advance for any help

 

The rear axle pinion needs to be parallel with the transmission output shaft at ride height (assuming a one-piece driveshaft here). You don't need fancy CV joints or other sorts of tricks. If the pinion and trans are not with in a deg or so of each other (i.e parallel), you will burn through u-joints fairly quickly. It should not be that hard to find a shop on the east coast to do the work correctly. It is a fairly simple task.

 

If you filled out your profile a bit more, some one might be able to direct you to a reputable local shop, or, maybe even help.

 

The other choice would be to run a CV Joint Driveshaft-a more expensive option for sure, but it will stop vibration (you may have to only do one end)-

 

Holy shit that’s gotta just eat parts.

Trans should point down 3deg and the rear should point up 3 deg.

Let us know where you are and we can find someone who can help you fix this instead of taking your money and still having it fucked

 

In order for this to work without vibrations you have to point the pinion at the transmission.

 

Thank You All for the advice...The problem is I live in a very small rural area in West Virginia..This housing rotation has been already attempted 3 times..Twice by myself and a friend with welding experience and secondly by the mentioned shop. The housing in the car and traction bars will not take another cut and weld. Every time it's been attempted the car was sitting at ride height but after the procedure it always seems to come out more negative than the initial setting. I have spent over 2K in the rear end and transmission etc trying to fix this problem...A few more dollars really won't make an difference now as I am over invested in this car...I sold a very nice body off big block 55 210 to purchase this thing and have as mentioned yet to have a pleasant drive. I contacted 3 places online about having custom drive shaft made. Two of them told me to turn the axle up further and one never responded... I have read over and over about parallel angles etc and I understand the purpose and whats needed...I just can't seem to make it happen..Thank You all Again

 

Where abouts in WV are you ,Northern panhandle , Eastern panhandle , South, middle of the state? Bill

 

I don't see where you mention how the rear Axle is mounted. How about some photos. You may have other options once we can see what your working with. It don't add up to how things can change once it's cut loose and re done then to change once set on the ground.
The Wizzard

 

Really need a drawing or picture. What's the traction bar set up like?

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Somebody May correct me if I'm wrong but as I understand a double cardan universal joint gives you twice the allowable angle variation. Plus the driveshaft is constant velocity then. That's what I did on my build and have no problems whatsoever.

 

I am about 35 miles south of Morgantown....The traction bars are made out of square tube with plate welded on the sides and then cut out and welded to the axle housing..They have a heim joint on the end that is attached to a bracket welded on the inside of the frame rail between the door opening and fender cut out.

 

If there is a noise coming from under that car from pinion angles..tranny angles engine angles .there should be/has to be some witness marks. When youre decelerating the pinion should move down not up. Have you looked anywhere else under the car to see if maybe a exhaust pipe is rubbing?

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Before you cut the arms off the rearend tubing again, try a narrow piecut in the traction arm from the bottom. This will close up and rotate the front of the axle upward. Tack weld and set the car on it's wheels. If it's now good, weld it solid and put a fishplate over the joint.

This whole problem is the reason guys shouldn't build suspension without adjustability in it. But it's too late for you this time.

Might also require a heat and bend of the spring hangers since their angle will change as well. But wait til the driveshaft is correct before you adjust the spring hangers.

 

I think the noise was the yoke slapping around in the back of the transmission. After we rotated it the first time from the initial minus-12..It got rid of 90% of the noise...How I think this helped was more yoke engagement in the transmission from rotating it up. It appeared to have around 2 1/4 of a 3.5 yoke sticking out before. There is still some noise but not nearly as bad..But still not right...I never thought of pie cutting the bars...Sounds like an option should they be cut at close to the housing as possible? I would assume the meaning of "pie cut" is a V shape and just not cut completely through but almost?

 

I'd cut them with a cut off disk about a 1/16" thick to start, from the bottom up, but leave the top side alone. Can always remove more if needed. Make the slit about 4" forward of axle centerline. Make sure to support the car so the blade doesn't get pinched when you finally make it through.

As for the yoke, the common length is to have it 1" out from bottoming when the car is at ride height. Maybe a little more, but definitely not 2.25".

 

This is just plane WRONG!!! The transmission and pinion need to be parallel, not pointed at each other. Also the yoke should be pushed in all the way till it bottoms out in the transmission, then pull it out one inch and that is where it should be at ride height.

 

I should try to achieve a positive pinion angle of +2.3 since my transmission is negative -2.3 I assume that is correct? Also that is a single cut and not a double V shape that would remove an actual section of the traction bar is that correct?...Sorry after 30+ years of working on and restoring cars this is the first time I have ever had to deal with this.

 

He’s literally agreeing with you.

 

And you can buy all the fancy driveshafts you want, this set up is still going to do exactly
What it’s doing.

Guys please,
For the love of god find this guy a local hamber to help him get this mess sorted

 

Yes your angles are correct.

Your pictures a little hard to make out. Is this like a truck arm suspension? Two lower bars welded to the rear axle with joints at the front?

 

I will take better photos and post this evening before I do anything else..Thanks Again

 

If you have a non adjustable mounting point for the front of the suspension arms, couldn’t he just make a new hole above the one he’s got to rotate the pinion up?

I would say that he might have to heat and bend some bind out of his spring hangers but realistically if this things at -5 and was -12 it probably has way more existing bind and rotating it up might get rid of some.

—-NOTE to original poster- hope I’m not coming off like a prick, I’ve just seen people throw piles of money that don’t have at solutions that aren’t going to work. I don’t want you wasting your money on a bandaid. My quest for a local guy to help out is just that, a man on the ground that can steer you rigjt

 

With the yoke that way I'd think (from experience) that the The yoke has vibrated enough to wallow the tail shaft bushing out by now.
When I first got my truck together in 1973 I had too short of a drive shaft in it and did that on it's first road trip. When you slide under it and wiggle the driveshaft up and down how much movement does the yoke have in the bushing?

 

ahhhhh !! Another pinion angle thread.

 

You have some good advice here. Just because a Guy tells ya he can weld don't mean he knows how to correct you issue. You've learned that lesson. Crankshaft angle must be the same as the pinion angle and not the Pinion pointed at the trans output shaft. In other words 2 lines in parallel with each other. The space above and below each of those is what the U-Joints take care of.
Now, if your traction bars are mounted incorrect to the chassis you will never get those two lines to stay correct to each other.
The Wizzard.

 

Pointing at each other and parallel are not necessarily the same thing.If they were on the same axis yes they could be pointing at each other, and be parallel. But raise one of them and they are not pointing at each other but are still parallel. Think about it.

 

Can you get it up here to Ohio?
We'll fix the pinion and you'll be happy.


These pinion angle threads are packed clear full of amusement. Typing into them is futile and reading them till your eyes bleed is likely to not help any.

The ONLY thing that is imperative is that u joint working angles are equal, that's it. The rest of the crap (up-down, parallel) is a detail your forced to work with in order to achieve EQUAL u joint working angles.

 

Yeah, I know. I still think he was just over simplifying his answer.

Given the trans and the opinion and pointing totally different directions I guess saying “- good starting point would be pointing them at each other”

Anyways let’s stop the pinion angle snow ball from rolling and help this guy get his shit fixed correctly.