I think you answered your own question. It sounds like the driveshaft is too short. Have the new one balanced with the yoke if possible. The word on the street is "no more than 1" of yoke exposed"

 

Yeah some times when you put it all down on paper ( or the net ) the answers jump out them selves. Tomorrow I will make some calls just to make sure what the other options maybe.

will look for new U joints. I know the stock drive shaft takes 1300 serries, my 9" takes a 1350 i believe, So i will need a special u joint. I used to have the part number but forgot it. I also know that the slip yoke has takes a different u joint aswell. So ill need 2 odd ball u joints.

 

U joints come in 1310, 1330, 1350. 1350 were not used by the factory. Sounds like you need a 1330/1350 conversion joint.

Note: if the driveshaft is 1310 then replace it. You do not want to run 1310 if you are making any kind of power at all.

 

yeah the drive shaft is a 1310, The 1350 drive shaft i have is 48" center to center, 2" to short for my application.

Any one happen to know how much degrees the rear end gets thrown off when using 2" rear drop springs?

What I've found out so far about my set up; mopar spring perches, 2 1/2" wide 4 leaf springs out back, 5/16" leaf spring center pin, stock drive shaft will use 1310-1350 and 1310-1330 u-joints.

I need to buy a angel finder. As of now I'm some what sure of how to find out the pinion and tail shaft angels, as well as the drive shaft angle, to land on the correct degree shims to purchase. However I am not sure If I want to go with the shims that weld on the axle. I may want to switch out to different spring heights for bigger wheels, which will throw off the pinion angle again. So the bolt on ones, that are held by the center pin are the ones to go with. I just need to find a good source for these with the 5/16 hole machined in it.

Or am I supposed to buy any size and machine the hole myself?

Best options? Ideas?

My complete total If I do the correction my self, and I magically prevent trani fluid from spilling, is around $100

Local 4x4 shop guy gave me an estimate over the phone, for around $150, + cost of u-joints, which on summit makes up for 50 dollars on parts. So basically $200 +- .

Im broke have $70, have to ask gf for money to do this job. So WHAT WOULD YOU FELLOWS RECOMMEND!?

 

I should add the climate is 100* average during this time of year, and I have no shade except what the car makes. So that should be a factor.

 

Do not borrow money from gf to fix car. Walk or take the bus first.

You can thank me later.

 

is 1/2" of slip to little? As of now with the ford slip yoke i have 1/4" of slip with the stock drive shaft. If I install my swap slip yoke, I will have 1/2" of slip.

I really dont want to pay to get a drive shaft retubed, or shortened for only 1/2"

 

as far as the drive line angle went the pinion angle is at 2*, compared to the 0* on my drive shaft, and the transmission angle is at 2 1/2* so its basically dead on. only problem is drive shaft.

 

any one?

 

1/2" should be ok, you're measuring with the"car on the ground" right?

 

Couple things that might help you find your problem. First, the obvious. Put a magnetic base dial indicator under there and check shaft runout. I've had quite a few of the long style pinion yokes be way off brand new out of the box lately. And one on a Currie 9" center just the other day. That's a story for another day though as far as what their tech tried to bs me through.......My guess is your suspension setup from what I read above. Trans yoke "needs" a minimum for travel but as long as the yoke collar extends past the tailshaft bushing (inner leading edge) length isn't an issue. You posted degree readings from trans/shaft/pinion. Are they in relation to a 0 level chassis or just numbers to compare? My guess is your 0 d-shaft angle giving you some reverse angles u-joints won't run at without vibration. In a perfect world the crank centerline runs completely through the trans, d-shaft, and pinion, with no angles present. A straight shot. And, from the factory they're very close like within a degree to compensate for a needed working angle that helps a u-joint live. And cancel each other. (not getting into tq wrap pre-load/un-load for simplicity sake). I'll try to keep it simple and short but I've had a few so.......You said you read 2.5 on the trans, 0 on the shaft, and 2 on the pinion. That would give you joint working angles of 2.5 front and 2 rear which is ok and shouldn't cause a vibration. U-joints need at least 1 degree to self lubricate and no more than 3 to self cancel harmonics. But, and here's the problem, once the d-shaft angle reaches 0 or less, the u-joint angles are compounded rather than working together to cancel each other. Picture this. And I'm just using numbers. You have your trans at 4 degrees down, d-shaft at 3 degrees down, and pinion angle at 4 degrees up. (again, no tq wrap taken into account) You have a 1 degree working angle at "both" ends which makes for a happy vibration free driveline. Now, raise the pinion to where the d-shaft is at a 0 angle between trans and pinion. You now have a pinion angle that is +4 degrees and a trans angle -4 degrees from d-shaft centerline. That's 4 degrees either end and a working angle of 8 degrees. Once above 0 plane the angles are added rather than cancelling. Way way way out of usable harmonics cancelling as well as u-joint life. And there really is no fix for that as far as angle shims. You can make it better, but not eliminate it. Shimming the tailshaft up and pinion down will help but in a leaf spring car the d-shaft has to be at the very least 2 degree down slope to have room for axle wrap alignment in a street driven car with no vibration. Or minimum vibration. Drag cars will be setup as much as 7-8 degrees down angle on the pinion and tq wrap will make it a 0 on accelleration. Another thing to consider is pinion offset. If the rear was done right the 9" should have an inch and a half offset via tube length to center the pinion and not introduce compound u-joint angles. Like going down and right or left. Easily seen from under the car if the carrier is centered but again, I've seen some "bolt in's" from several big name vendors that are off considerably. Sorry for the long post I tried to keep short but hope it helps you find your problem.

 

I vote for a balance issue. Either driveshaft out even rear tires. Is this a recent T5 conversion? If so, are you driving at higher speeds than normal? This might not be a "new" issue. A new drive shaft is in order from what you described... Balancing your rear tires might be helpful as well.

 

The fact that you're feeling more vibes while coasting leads me to believe it's a driveshaft balance issue.
When you are accelerating, the driveshaft is under constant load, therefore you "feel" it less. It's still there, you just won't notice it until a u joint let's go, causing you're driveshaft to fall to the ground and cause serious havoc. You will feel that.
Your best bet is to measure for proper driveline length, factoring in 3/4 inch of slip yoke showing. Then get one made.
And I have to agree with an earlier poster about the girlfriend. Avoid borrowing money from her at all costs.

 

I just went through the same exact thing. T-5z conversion. Out of the throttle deaccelerating from highway speeds presented a bad vibration, was even worse with the clutch in. The car was eating rear U-joints every 300 miles or so, turned out to be a misbalanced driveshaft. I went with an aluminum one from Shaun at S&T and haven't had any issues since!

 

Had the drive shaft changed, put a 4 degree shim out back to get the angles pointing parallel to one another, I now have 2 1/2* on the ts, and 3* on the pinion.

Now with the vehicle loaded on all 4, the drive shaft has 1/2 of slip, and no longer makes the messed up clunking noise, just a light tap every once ina while, beleive it is do to the fact that its not rolling on the ground. No more vibrations up to 3 k, and no vibrations on sudden decel.

seems like the problem was solved. I will no more after I drive the car to work today.

 

Thanks alot for the info guys, Rickgto, I read alot about axle wrap up, and the set of springs i bought were supposed to prevent that from happening. If this does occur I will replace the 4* shim with a 2* to give me that extra degree or 2 for sudden accelerations. So that the angels remain parallel.

 

total cost came up to 85 dollars. compared to the 200 dollars at the shop. And I learned alot.