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Vibration - pinion angle? Need advice.

  • Thread starter Deleted member 214
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Deleted member 214

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My Tremec was hitting the tranny tunnel and the shop "fixed" it by dropping the tail. Now the shifter rattles like a low pitched rattlesnake under load. I checked pinion angle - trans is 5 degrees down at the tail, driveshaft is level, the Dana is level. I hear that there should be similar angle numbers both ends. I am figuring if I install a 2 degree wedge under the axle dropping the nose, that would give me 3 degrees up front and 2 degrees in back, solving my problem. However, I read that the output shaft of the trans and the input shaft of the axle should be parallel. If I do that, I would have to raise the nose of the Dana and the angle at the trans would be even worse out of whack.

Help!
 
My Tremec was shoehorned in by a shade tree mechanic. Pinion schminion for me. Dana is where it was. The floor pan was cut and dimpled for clearance. It rattled/vibrated on acceleration. The provided Keisler crossmember crinkled on the first romp. A local machine shop fabbed a crossmember. No vibration. I doubt that this is a tight tolerance angle degree issue. I have been wrong before. My shifter rattles too at certain higher rpm's. Big difference between floor pan tap and driveline vibration. Good luck. If I had to do it again, i'd consider gear vendors.
 
I keep trying to get the word out about those dam trannies because I had the same deal with the one I HAD. With my currant setup I had a driveline vibration as well but had the tranny tucked in tighter at 3 degrees down with my driveshaft and pinion being nearly zero like yours, I shimmed the nose of the pinion up 3 degrees and life's great! You want the pinion pointed up the same degrees as the tranny is down to cancel out the vibration from there it's just a matter of testing and compensating for spring windup (mine never needed any further shimming). I know it's not what you want to hear but I'd get that tranny further up in the car than that meaning some significant cutting. Good luck

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My Tremec was shoehorned in by a shade tree mechanic. Pinion schminion for me. Dana is where it was. The floor pan was cut and dimpled for clearance. It rattled/vibrated on acceleration. The provided Keisler crossmember crinkled on the first romp. A local machine shop fabbed a crossmember. No vibration. I doubt that this is a tight tolerance angle degree issue. I have been wrong before. My shifter rattles too at certain higher rpm's. Big difference between floor pan tap and driveline vibration. Good luck. If I had to do it again, i'd consider gear vendors.

Boy you sure are hard to convince old man haha! If we ever get to meet someday I'll take you for a ride then pull out the shims (only takes 15 min) and then go for another ride.......... Then you'll be a believer.
 
Modern technology never fails to amaze me. Using your android or I-phone there's actually an app that uses your phone as a level and by plugging your tranny angle ( which the phone is used to measure ) and your drive shaft angle into this app it will tell you exactly what angle your diff should be on. Don't ask me to explain how it works but it does. Download it and plug in some known values and by God it comes up with the right answer every time. And nice part is you use the edge of the phone just like an angle finder and the calculations run in reverse also in case you just want to adjust the tranny angle.
 
I keep trying to get the word out about those dam trannies because I had the same deal with the one I HAD. With my currant setup I had a driveline vibration as well but had the tranny tucked in tighter at 3 degrees down with my driveshaft and pinion being nearly zero like yours, I shimmed the nose of the pinion up 3 degrees and life's great! You want the pinion pointed up the same degrees as the tranny is down to cancel out the vibration from there it's just a matter of testing and compensating for spring windup (mine never needed any further shimming). I know it's not what you want to hear but I'd get that tranny further up in the car than that meaning some significant cutting. Good luck

If I shim the nose of the Dana UP, not down, and make the trans and pinion parallel, the pinion angles would be 5 degrees at the axle and 10 degrees at the tranny. That would be worse, right?
 
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the angles need to be opposite to cancel each other
so open the floor and raise the transmission then adjust the rear end minus a couple to offset the axle wrap
 
Modern technology never fails to amaze me. Using your android or I-phone there's actually an app that uses your phone as a level and by plugging your tranny angle ( which the phone is used to measure ) and your drive shaft angle into this app it will tell you exactly what angle your diff should be on. Don't ask me to explain how it works but it does. Download it and plug in some known values and by God it comes up with the right answer every time. And nice part is you use the edge of the phone just like an angle finder and the calculations run in reverse also in case you just want to adjust the tranny angle.

If your talking about Tremecs app I'm not sold, I used it and had mine in the green (acceptable) even though it wasn't. I then matched the angles using a Clinometer app I downloaded and have been happy ever since.

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the angles need to be opposite to cancel each other
so open the floor and raise the transmission then adjust the rear end minus a couple to offset the axle wrap

Exactly, 5 degrees down at the tranny means 5 degrees up at the pinion. It's sad they say those are a bolt in deal, now your seeing what they call bolt in. Really you need to make more room and move it up but a 5 degree shim is easy enough to try.

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I keep trying to get the word out about those dam trannies because I had the same deal with the one I HAD. With my currant setup I had a driveline vibration as well but had the tranny tucked in tighter at 3 degrees down with my driveshaft and pinion being nearly zero like yours, I shimmed the nose of the pinion up 3 degrees and life's great! You want the pinion pointed up the same degrees as the tranny is down to cancel out the vibration from there it's just a matter of testing and compensating for spring windup (mine never needed any further shimming). I know it's not what you want to hear but I'd get that tranny further up in the car than that meaning some significant cutting. Good luck

If I shim the nose of the Dana UP, not down, and make the trans and pinion parallel, the pinion angles would be 5 degrees at the axle and 10 degrees at the tranny. That would be worse, right?

The tranny is 5 degrees unless you move the tranny. What happens when you move the pinion up to match is the pulses from the universals (they don't run in a smooth motion at an angle) cancel each other out and you gain angle at the pinion (zero angle is not good).

angle.jpg
pinion_angle_bad_angles.jpg

I don't agree with #1 pic being perfect, no angle at all means no bearing movement which equals bearing pitting poor lubrication and very short life.

You want #2 pic
 
Pic 2 min 2 degs so you get ujoint life
you also have to look at side angle as in motor off set and pinion not in centre
 
the angles need to be opposite to cancel each other
so open the floor and raise the transmission then adjust the rear end minus a couple to offset the axle wrap

Open the floor? You mean cut and patch the tunnel, then get a new crossmember? Trying to avoid that.

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Pic 2 min 2 degs so you get ujoint life
you also have to look at side angle as in motor off set and pinion not in centre

That is what I would like to have, but how can I do that without a torch and a welder? I hate shackles, but if I raised the rear of the springs that would angle the axle up while dropping the nose.
 
I'm having the exact same problem with my Tremec in my 74. One quick question.... When you say your Trans is 5° down, what are you comparing it to? What are you using as zero?
 
The angle finder I have is oriented relative to gravity, so 1 degree down would be relative to a line perpendicular to which way gravity pulls the angle finder. The changes I am aware of include: modifying the tunnel and shimming the trans mount or using a different cross member (the preferred way), changing the angle or height of the differential, or changing the engine height by shimming the K-frame to drop the front of the engine and level out the engine-trans. If someone had done the K-frame shim, I would be interested in hearing about it.
 
shim the k frame 1/2 in, it raises the tail shaft & gives more room to raise the xmember more
 
What is involved in shimming the K-frame? I assume it is more than just dropping the four bolts that hold the K-frame on, lifting the body, inserting shims and then replacing the bolts. question from a novice.
 
loosen the torsion bar adjusters & use jack stands & a floor jack, I made some spacers out of 1/2 aluminum, after you are all done do a front end alignment. you will have to bend trans cooler lines near the radiator
 
I have an A518 overdrive & no rear pinion shims .
 
I'm having the exact same problem with my Tremec in my 74. One quick question.... When you say your Trans is 5° down, what are you comparing it to? What are you using as zero?
What really matters is where they're at in relationship to each other. You want to check pinion angles while resting on its weight, I just put jackstands under the axle. I like to set the car level with the rockers then check angles just so it's repeatable plus pulling the driveshaft makes for a more accurate reading. Turn the pinion yoke facing up and down with the clamps left off to check it then check the trans angle either off of the tailshaft itself or the crankshaft pulley.

Like CDR is saying there's more than one way to get there but you need the angles to run parallel like the illustrations show while trying to preserve some angle at the joints for long universal life.

After playing with them long enough you'll be able to tell what needs done just by driving it, mine could still come up a hair...
 
What really matters is where they're at in relationship to each other. You want to check pinion angles while resting on its weight, I just put jackstands under the axle. I like to set the car level with the rockers then check angles just so it's repeatable plus pulling the driveshaft makes for a more accurate reading. Turn the pinion yoke facing up and down with the clamps left off to check it then check the trans angle either off of the tailshaft itself or the crankshaft pulley.

Like CDR is saying there's more than one way to get there but you need the angles to run parallel like the illustrations show while trying to preserve some angle at the joints for long universal life.

After playing with them long enough you'll be able to tell what needs done just by driving it, mine could still come up a hair...


Well I put her up on jack stands yesterday and leveled the car to zero according to the rockers. The Trans is down 4.40° and the rear was at 0°. I couldn't go up with the Trans due to tunnel hump clearance so I shimmed the rear up 4° and things are better but I still have that rattle snake in the shifter between 3-4000 rpm in every gear while accelerating. The higher the gear, the stronger the rattle and the harder I accelerate, the stronger the rattle. The rattle is not there in neutral regardless of clutch position. Engine is new and balanced, Trans is new directly from Libertys Gears. Bell housing was checked and aligned to perfection and pilot bearing is brand new from Hurst. The last thing I think to check is the worthless flimsy Keisler crossmember and mount. I just ordered a new member and poly mount from Hurst.
 
I'm also thinking the shifter mounting bracket is too flimsy and flexible which isn't helping the shifter rattle. I'm planning on taking it out and welding in a few gussets.
 
Awesome, glad that helped. I did a lot of cutting and welding to get mine at 3 degrees.
I'd check the tranny slip yoke for exessive slop or proper engagement (usually all but an inch in the tranny), look for any place the tranny could be touching the floor, double check your universals, rims are all torqued, etc. Good luck.
 
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