Could my driveshaft be bent, and how did it get that way?

I have never been able to go over 80 mph or so without the car feeling like it was rattling to death. I assumed lack of balance on tires and motor.

I have moved my floor shifter, and there is a 1/2" hole right under my right arm (from previous placement of shifter cable) where I can see the drive shaft. I was driving a couple days ago, and noticed that it seems like it wobbled while I was driving. So, I got onto a safe and empty stretch of road (I would not be paying attention to traffic for the next few minutes), stuck a ballpoint pen down the hole, and let it ride over the top of the shaft like a roller cam lifter. It went up and down, close to 1/2".

I think this is the source of my high-speed shimmies.

Any suggestions for straightening or balancing, or am I on the lookout for a junkyard shaft?

Could this be bent from the showroom floor, or has my hard launches with 180 Brute HorsePower bent it

 

If the driveshaft is bent, go look for another. You might also double check
to make sure your u-joints are seated properly in the u-bolts. If they are
not centered, you'll get a tremendous vibration and wobble. I'd pull the driveshaft and place it on a flat surface and roll it. It's possible it has a
counter weight on it also. You could also take it to the local driveline place
and have them check it for straightness and balance...just my

Don

 

better yet, yank it out and take it to drive line repair shop and have it checked, if all you did was get another one you might have the same problem, they can straighten and balance it for you and it's not very expensive,it'll save your tailshaft in the tranny in the long run and let you run faster than 80mph.

 

It could also be a worn or bad tranny mount allowing the tailshaft to bounce.
Let a driveshaft shop check the shaft out for you.

Seth

 

Would the "worn or bad tranny mount allowing the tailshaft to bounce" happen only at high speeds or all the time?

I tested it just idling at under 5mph, and it was wobbling.

I want to NOT be tranny related. Just driveshaft

 

if the drive shaft has been bouncing long you probley already have tailshaft and tranny mount problems. you can bet the u joints need replacing...frank...

 

I swapped the U-joints twice in two years. Once when I first got it, because it was old and rusty. Then again a couple months back when I replaced the gears. Couldn't see reassembing the differential and not replacing the $10 u-joint. (actually, the real reason I replaced it is one of the caps came off and I lost all the needle bearings )

What do I check, and how, with the trans mounts? Is it just a wiggle and watch type of check?

 

push up on the tailshaft and look at the trans. mount...if it is a c4 then you will want to change the tailshaft seal...i put tape around the u joint cups when i pull a drive shaft...frank...

 

I did not mark the driveshaft when I swapped u-joint. Is there a way to tell if I am in/out of phase, and can I re-line it? I don't think I turned the shaft or the differential when it was off, would that make a difference? Then again, I might have???

I am pretty sure the cups are seated all the way. I will check all of these things tomorrow morning. Just got done working on it for today. In texas, it is better to be done by 7:30am, when the sun comes out, it gets miserable.

 

if you are referring to my comment about straightening the shaft, replacing the tube is the way to go, but this young fellow is not experienced enough yet to know,so my suggestion is to take the shaft to a drive line shop for repair, i know you can't straighten a tube but he might not, that's all i'm saying. also if his shaft has ever been removed(like he said he has) then it's not in sinc anyway! he can just line the grease fittings towards each other, on the same side and hope for the best unless he's willing to spend the $$$ to do it right.

 

What the heck is this in sinc thing? I thought that was only for big trucks like my F250 that have 2 seperate drive shafts that connect to each other half way under the truck? I've had my drive shaft out several times and completely replaced the drive shaft with one from another car and have not had a problem. How do you know if your drive shaft is not in sinc?

 

I took the driveshaft off today and checked it with a "straight-edge" which, I agree, is not the most scientific or accurate way to check it out. It looks straight. There is also no play at the tranny-shaft junction. So, I just rotated the shaft 180 degrees.

I haven't had a chance to run it fast yet (just finished the cutting of the front springs to lower the front and don't trust it yet) but will try it maybe tomorrow and see if it solves the wobbles.

Also, in the process of working on this, I read the Mustang II Chilton manual, and it says to put run it at 40-50 mph while on blocks, run a line on it, then put 2 hoseclamps on it at 180 degree (screws opposite of each other) at the rear end of the shaft. They say to run it, and if it still wobbles, turn one about 45 degrees, and repeat until the wobble goes away.

Sounds kinda scary to me.

Trust me, I can scan the page if you don't believe me.

Anyway, lowered the car, and it looks great, even with worn out 195/60r15s on it. Check out the "cutting the springs" link.

 

I bent the original driveshaft in mine,, dunno how I did it.. but probably due to some pedal to the mat stuff and release of clutch in a quick manner. I had a new and stouter shaft made,, bout $150.00. Stopped at an old buddies garage today. He showed me his old driveshaft which he had torn in half. wow!!!
Dan

 

My cousin has a jeep, he tore the rear drive shaft in HALF. I mean, take a banana, twist it until the front half rips off the back half, and that is what he has!!!

Being an idiot Chrysler driver, he took the rear drive shaft out, and is now driving front-wheel-drive only. Apparently, there are 4 different shafts for that year model, and he cannot find the right replacement.

As for mine, it appears straight, but I think I hooked it up out-of-sinc when I changed the gears and U-joints. I turned the shaft 180 degrees, but have not had a chance to test it out yet.

I doubt I have bent mine. I don't think 180 HP, even with a spool, will twist my shaft.

 

All of my Mavs have the 75 mph shake and rattle...even the six bangers...I look forward to hearing what you find out.

Nice detailed website BTW...I like it when folk detail everything.