t5 issues

From the number of times I've seen your situation posted I'm guessing it happens allot.

My first guess is you may have a drive line angle issue.

Quite a while ago I worked out how much difference drive line angles were changed by shortening the drive shaft a couple of inches, shortening the shaft increased the angle of incidence 1~2 degrees at the rear yoke, IIRC.

I would degree the drive line/power train.

As to why the pattern of vibration changed? I could speculate all day and still not get the answer. And it may not be any one thing.

Did you get the U-joints from Sadler? They installed mine but the caps for the yoke were a bit too big and the needle bearings started to come out the seal which caused about the same type of vibrations you have.

StangIIttop said:

Did you get the U-joints from Sadler? They installed mine but the caps for the yoke were a bit too big and the needle bearings started to come out the seal which caused about the same type of vibrations you have.

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A 'change' in the U-Joints (by being driven) would be one of my speculations. Heat, wear, binding, etc.

How the hell do they get the wrong caps on a new set of joints? They come as a set. More than likely they lost needles during install?

LILCBRA said:

I am not sure if the angle is too far off, but it could be. It seems to be a pretty straight line, but I could be wrong-never actually measured, just more of an eyeball look. I will try to measure it at least up and down to the floor.

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You'll need a machinist protractor or inclinometer/angle finder.



Problem with inexpensive inclinometers is they can give different readings when measuring from different directions or the other surface on the gage.

LILCBRA said:

As far as measuring the angle, what I was going to do with it was get the car off the ground as level as I can, then with the driveshaft out, I was going to measure the centers of the tailshaft and axle to the ground. Trick is with either way you go, with either the angle finder or just measuring, the car has to be level. Where do you check for level-the rocker panel? That seems to make the most sense to me, but I just don't know.

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Only way I know of that works is using a protractor head or inclinometer.

Level is irrelevant, and the suspension should be normally loaded (IE: Over a pit, on an alignment rack (or similar lifting device), rear wheels on blocks with stands under the front cross member, and so on).

Years ago I chased this s**t around, lots of stories there, some even funny.

I pulled the last "factory installed" engine from the last car with a factory 8", and as the engine and trans cleared the engine bay I realized I forgot to measure the angles before pulling the engine ... Kick myself in the ass! Now I have to stick the frigging engine/trans back into the frigging car to measure the frigging angles before the rear is swapped because it's going to be my last frigging chance to personally acquire that frigging data.

LILCBRA said:

I was just having a thought, and I don't remember ever seeing anyone checking, changing or mentioning it. Is the II yoke OD the same as the T5 yoke OD? I guess where I am going with it is if there is a difference, couldn't the original vibration have been from the difference in the bushing ID and my yoke's OD? Then the sudden change could be from maybe the bushing and/or tailshaft housing cracked? Like I said, it is going to be a couple of days before I can get underneath it, so I am just speculating, but it seems to make some sense in my mind right now.

As far as measuring the angle, what I was going to do with it was get the car off the ground as level as I can, then with the driveshaft out, I was going to measure the centers of the tailshaft and axle to the ground. Trick is with either way you go, with either the angle finder or just measuring, the car has to be level. Where do you check for level-the rocker panel? That seems to make the most sense to me, but I just don't know.

Click to expand...

You don't need to do anything fancy. You don't even have to remove the driveline and car should be on the ground or positioned as such. Just put a magnetic degree (finder)scale (easily found at home depot) on the yoke in the tranny with the yoke's u-joint ear 'down' and then place another scale on the rear axle's yoke (should also be down as the ears on the driveshaft should be clocked the same) now compare the angles in degrees. Also seen adapters or round magnets that are designed to 'sit' right on the u-joint caps themselves at each end... in cases where the yoke is not square with the face of the u-joint cap. Compare the readings on both scales and make your adjustments.

Here's a couple links to a good articles explaining it all.
DRIVE LINE PHASING

Inland Empire Driveline Service, Inc. - Driveshafts, Pinion and Transmission Yokes, Center Support Bearings

Also wanted to add-

Check the torque on the pinion nut on your 3rd member (rear axle pinion @ the yoke)
I've been finding 9" fords fromt he late 60s and 70s have been working the nuts loose causing the pinion yoke to slide forward and become loose causing occasional vibrations and quick destruction of the rear u-joints. I have yet to run into a case with the 8" rear but have found at least 4 different cases with the 9" rear, mostly in trucks.

Dano78 said:

You don't need to do anything fancy. You don't even have to remove the driveline and car should be on the ground or positioned as such.

Click to expand...

Fact is the shaft can't be measured with it out of the car.

Here's a couple links to a good articles explaining it all.

Click to expand...

With all due respect, Not really.

DRIVE LINE PHASING[/quote]

I've worked with drivelines and drive shafts on my cars, fleet trucks and installed equipment and the above artical left me scratching my head. The author was going back and forth between cars and trucks which are the same but different, and doesn't explain relationships, etc.

Take the following illustration:




Wrong is Right for a leaf sprung vehicle in motion at "speed", speed being ? 30-40-50-60 mph? and above ?

THe author does write this: Normally the pinion gear angle is a negative angle and the nose of the rear end is pointed down. This allows for the upward movement of the rear end when torque is applied. Those who follow racing will know the term spring wrap. Setting up a drive line for racing situations or high torque off-roading is different and much more complicated than for street vehicles, as many more variables enter into the formula.

A Story:

When I was a kid I had the rear axle of the '71 on stands and spun up the drive line like we do when we're kids. I noticed there was a vibration ~ 40? (this was a long, long time ago). So I watched under the car while playing with the throttle. (Speeds are for purpose of illustration only)

At low speed there was no vibration, then as I gradually increased speed there started a vibration. In looking at the chunk I saw it was getting a little blurry. Continuing to gradually increase speed the rear yoke would pop up - no vibration- drop down - vibration - pop up - no vibration - and so on. Increasing speed a bit more the rear yoke popped up and stayed up and didn't vibrate.

Apparently the physics of the spinning drive shaft created forces about the rear yoke resulting in the rotation of axle to a point the physics of the drive shaft locked the axle in position, apparently where the system was going through a minimum change in velocity. The minimum change of velocity is when the system is in as straight of line it can get.

In my observation it was only the physics of the drive shaft causing the change of angle of the pinion. In operation there is hte "torquing" of the axle and climb of hte pinion from "pushing" the car.

So in the above illustration wrong is right for a vehicle in motion, the physics involved "lifting" the pinion till the system in in a straight line.

At least this is the way it is suppose to work in a leaf sprung automobile!!!!

Also, in the above illustration, both pictures are the same. In both pictures the driver (engine and trans) and driven (pinion) lie in the same plane so rotating the axle will take both systems out of phase.

Phase, I forgot to address that, sorry. In a U-Joint system there are two acceleration and decelerations per rotation (unless both driver and driven are in a straight line). So now you have a joint on each end of a shaft and when the driver is accelerating the shaft the driven is decelerating the shaft keeping a constant velocity.

I didn't want to get into any of this .....

Inland Empire Driveline Service, Inc. - Driveshafts, Pinion and Transmission Yokes, Center Support Bearings

Click to expand...

When I forst looked at the illustration on this site I thought Madness , shear MADNESS!!! The shaft will rotate into knuckle city.

Then I realized it was a toy car site. And their using heims. Heim joints don't allow the axle to rotate so the driver and driven have to be set in the same plane.

Then tere is factory 4 link (sic) and the bushings allow a little play.

Leaf springs? Axle wrap is our nightmare.

I'll re read this and see where I forgot this or that, where something could have been written better ... it's not a term paper.


Conclusion ...

Leaf sprung automobile drivelines are designed so the rear axle rotates into a straight line thus everything is in phase and everything is spinning at a constant velocity resulting in a nice cushy ride.

Truck drivelines, otoh, such as my Toyota 4x4, will never be in a straight line, the system is designed for the axle to rotate (sort of,) into phase. The truck will always have some vibration because the drive shaft will always have two accel/decel cycles per revolution.

Continued later .....

Dano78 said:

Also wanted to add-

Check the torque on the pinion nut on your 3rd member (rear axle pinion @ the yoke)
I've been finding 9" fords fromt he late 60s and 70s have been working the nuts loose causing the pinion yoke to slide forward and become loose causing occasional vibrations and quick destruction of the rear u-joints. I have yet to run into a case with the 8" rear but have found at least 4 different cases with the 9" rear, mostly in trucks.

Click to expand...

And heres a funny thing.

Shortly after buying the Toyots the rear pinion seal started leaking. I had it fixed (Warranty) and when I got the truck back it had a vibration. WTF? Of course the dealer couldn't feel it ... WTF?

As time went on, a couple 10k miles or so, the vibration got worse and locking in the front hubs would turn the truck into a vibrator.

They traced the initial vibration to the Tech having over-torqued the rear pinion nut (which took out the bearings making the vibration worse).

Wow, an overtorqued pinion nut causing vibration... learned something new.

Something needs addressed.

I have an AOD I want to install in one II. The transmission cross member is the hang up as I believe I'm going to run into the same problems as those installing the T5, that being relocation of hte cross member or other mods needed to support the transmission mount.

In one car it wouldn't be a problem, I only need to attach the cross member to the sub frame connectors (actually a frame). The car I want to install the AOD in needs to remain stock, or able to be returned to stock, so welding and hole punching is well out of the question.

I mention this to let you know I feel your pain. .....

I have seen only ONE person relocate the cross member in an acceptable manner.

From what I have seen most have handled the relocation of hte cross member by simply getting a couple of pieces of pipe and long bolts.

While it may work it is a solution that is far from sound engineering. It creates a bouncy flexy mount which could create or aggravate vibration. It is most certainly weak.

More later.

My car has a vibration also. It starts at 75 and at 80 its bad. I will have to measure the drive line angles. One thing is my car has lifted leaf springs in the back they are not stock I think it is raised about 2 or 3 inches. I also have the southside machine bars and those change the pinion angle. They maybe for stock springs only. I will have to drive it with the fronts loose and see if that has any effect. I have gone 120+ with the car and it was fine the only things I changed since then were the rear gear 3.40 to 3.80 and installed the lift bars. I will have to measure the angles in the next couple days.

I measured mine yesterday and I got on the back of trans 4 degrees down, and the pinion was 7 degrees up. What the hell does this mean? I am going to try to get the trans down 1 degree to 3 and I am going to install 4 degree shims in the back to point the pinion down to 3 degrees. Then that would be 3 down 3 up so then I guess that would be the ideal situation.

Wow.

1) When measuring this the cars rear suspension needs loaded as though it's sitting on the ground. The rear axle needs set on blocks or stands or the tires on blocks, the front wheels need to be on blocks or the front held by stands on the cross member (on a line between the spindles). I've had the back on blocks and the front frame rails on stands in the header area and notised when lifting from the cross member the rear pops up or down when coming off or going on the front stands.

2) as has been stated, the inexpensive inclinometers arent to be trusted, Their repeatability needs verified. IE: Mine will read 1 ~ 1 1/2+ degree different depending. IE #2, If I measure from the tail shaft of the trans and the measurement is 1 degree off true, then rotate/spin the gage 180 deg and measure the rear and it reads 1 degree off in the other direction it's actually reading 2 degrees off.

3) Unless measuring from the machined surfaces of the yoke your probably not getting a good reading. I don't remember seeing a factory yoke with other than the cap surfaces that could be considered measure worthy. So you need to seat a set of caps in the yoke, or figure another way to measure from the machined surfaces.

I get the tail shaft angle from the front belt pulley/dampener. Luckily I have a 2' steel rule so I can drop a parallel measuring surface about 14~16" under the pulley. Any straight and parallel item of sufficient length will work.

Doing it this way I can measure from the "right" in the front and from the "right" in the back and inaccuracies in the inclinometer matter little if any.

4) Then that would be 3 down 3 up so then I guess that would be the ideal situation.

Um, Yeah, that is called 'in phace' and is the ideal situation with a car in motion. Not at rest.

The force needed to move the car rotates the axle causing the pinion to climb.

When you start in phase the pinion rotates/climbs out of phase. I did this ... once. At 55 the rear end banged/slammed so badly it sounded like it was going to come up through the bottom of the car.

So you want to set the pinion "low" so the axle rotates and the pinion comes into phase.

In an ideal world when the pinion comes into phase the trans shaft, drive shaft and pinion would be in a perfectly straight line*.

How low to set the pinion ... I believe the figures are ~ 3 1/2 degrees for a 'street driven' car, and up to 7 degrees for a purpose built straight line car. Of course this only applies to leaf springs.

* One of the things that make the "straight Line" a laugh is the IIs drive shaft isn't "straight'. The 'shaft' doesn't leave the trans at 180 degrees nor enter the rear at 90 degrees. Thus there will always be a measure of vibration. The best you can hope for is to minimize vibration.

I believe that's why the II came with soft engine and trans mounts and rubber freaking mounted rear ends.

I am still working on mine. I will get to it this week end maybe. Now I noticed my ssm bars pointed the pinion way up when the fronts were bolted to spring. I do have differant springs in back taller. That was probably throwing it all off.

Wart said:

Wow.

1) When measuring this the cars rear suspension needs loaded as though it's sitting on the ground. The rear axle needs set on blocks or stands or the tires on blocks, the front wheels need to be on blocks or the front held by stands on the cross member (on a line between the spindles). I've had the back on blocks and the front frame rails on stands in the header area and notised when lifting from the cross member the rear pops up or down when coming off or going on the front stands.

2) as has been stated, the inexpensive inclinometers arent to be trusted, Their repeatability needs verified. IE: Mine will read 1 ~ 1 1/2+ degree different depending. IE #2, If I measure from the tail shaft of the trans and the measurement is 1 degree off true, then rotate/spin the gage 180 deg and measure the rear and it reads 1 degree off in the other direction it's actually reading 2 degrees off.

3) Unless measuring from the machined surfaces of the yoke your probably not getting a good reading. I don't remember seeing a factory yoke with other than the cap surfaces that could be considered measure worthy. So you need to seat a set of caps in the yoke, or figure another way to measure from the machined surfaces.

I get the tail shaft angle from the front belt pulley/dampener. Luckily I have a 2' steel rule so I can drop a parallel measuring surface about 14~16" under the pulley. Any straight and parallel item of sufficient length will work.

Doing it this way I can measure from the "right" in the front and from the "right" in the back and inaccuracies in the inclinometer matter little if any.

4) Then that would be 3 down 3 up so then I guess that would be the ideal situation.

Um, Yeah, that is called 'in phace' and is the ideal situation with a car in motion. Not at rest.

The force needed to move the car rotates the axle causing the pinion to climb.

When you start in phase the pinion rotates/climbs out of phase. I did this ... once. At 55 the rear end banged/slammed so badly it sounded like it was going to come up through the bottom of the car.

So you want to set the pinion "low" so the axle rotates and the pinion comes into phase.

In an ideal world when the pinion comes into phase the trans shaft, drive shaft and pinion would be in a perfectly straight line*.

How low to set the pinion ... I believe the figures are ~ 3 1/2 degrees for a 'street driven' car, and up to 7 degrees for a purpose built straight line car. Of course this only applies to leaf springs.

* One of the things that make the "straight Line" a laugh is the IIs drive shaft isn't "straight'. The 'shaft' doesn't leave the trans at 180 degrees nor enter the rear at 90 degrees. Thus there will always be a measure of vibration. The best you can hope for is to minimize vibration.

I believe that's why the II came with soft engine and trans mounts and rubber freaking mounted rear ends.

Click to expand...

So then my 4 degrees down and 7 degrees up will change to say ten up under load. I thought the numbers have to be within 1 degree to be vibration free. I plan on drag racing this car. So 3 down and 1 or 2 up? And then under load it will maybe go to 4 or more?