The Stovebolt Site Forums The Shop Area Engine Shop Forgot to mark driveshaft before removal...

Anyone ever forget to mark their driveshaft before removing it and after you reinstall it, you have severe vibrations at ~65mph?

well, that's what i did. =/

I'm thinking that to fix the situation, all i have to do is rotate the driveshaft 90 degrees (4 bolts) and rebolt it up.
if the vibration doesnt stop, i do this until it does stop.

4 positions total (90 deg apart) for the driveshaft to be installed--i think.

OR am i screwed??

what are your thoughts on how to fix this?

Thanks,

mechttu
houston, TX

What make, model/size, year, engine, rear end?

1966 Chevy Stepside.
12-bolt/3.73 gears--no posi.

350 chevy (1990 year, i think).
700R4 tranny

i guess my question is "How do i fix this?"
(i have a tendency to ramble thinking all the side-details are important too)

Think about it; the position that the drive shaft is installed should not matter. The drive shaft is balanced as a unit, it is not balanced with the trans or the rear diff. What you do have to consider is the "clocking" of the u-joints. If you drive shaft is such that removing it can change the relationship between the u-joints, then your method of resolving your viberation issue should work. If both u-joints are attached to the drive shaft, then I would thing there is something else wrong.

So some questions:

Did it viberate before it was removed?
Did you change anything on the drive shaft?
Did you change anything else that could cause the viberation?

or, why was it removed?

>> "Did it viberate before it was removed?"
no. the problem developed after i pulled the driveshaft to fix my speedo gear ratio

>> "Did you change anything on the drive shaft?"
no. the only thing i can think of is that i was supposed to mark the position of the driveshaft before i pulled it. as i understand it, a driveshaft is balanced with weights. (am i wrong?)

>> "Did you change anything else that could cause the viberation?"
no. nothing else was changed that would cause the vibration. HOWEVER, i do know the u-joint coming out of the bell housing will "thunk" as i rotate it back and forth. initially, i thought my rear end was bad. however, after reading that i was supposed to mark the position of the driveshaft, i'm starting to think i need to rotate it 90 degrees and rebolt it to see if that will cure my problem.

>> "or, why was it removed?"
i pulled it to change out the gears for my speedo to work properly. =/

so, i'm back to my original question...
Will rotating the driveshaft and rebolting it 90 degrees fix my vibration problem? (and keep rotating it until the problem is fixed)

Has anyone else done this?

couple of things to consider. if it is a 1 piece d/shaft and you didn't cut it it shorten it there should be no prolem with the shaft. if you put iyt in the vise to remove a ujoint and tightened it up on the tubing then you quished it and possibly bent it. if you didn't alter the shaft or remove any you joints then you can't put it back in wrong
the thing that more than likely happened is that a ijoint cap came off and a needle or 2 dropped and is trapped in the nnd of the cap causing you a problem.
If it is a 2 piece d/s then there are a few ways to screw up the mechanism if you took it apart, but will await your response on why you removed it and what for
ron

>> "couple of things to consider.
if it is a 1 piece d/shaft and you didn't cut it it shorten it there should be no prolem with the shaft."
yes. the driveshaft is a NEW one-piece unit. it was installed at the same time my tranny was installed back in March (no vibrations then).

>> "if you put iyt in the vise to remove a ujoint and tightened it up on the tubing then you quished it and possibly bent it."
nope, no vice/ no crushing

>> "if you didn't alter the shaft or remove any you joints then you can't put it back in wrong"
ok... =|

>> "the thing that more than likely happened is that a ijoint cap came off and a needle or 2 dropped and is trapped in the nnd of the cap causing you a problem."
YES!!! a cap did fall off and hit the ground. i never saw any needles tho. i just picked up the cap and pushed it back on the u-joint--then reinstalled the snap-ring. i realize i shouldn't have been messing with the u-joint to remove the driveshaft, but this was my first time under there and i wasnt sure HOW to get my driveshaft out to access my tranny's tailhousing.

so, not knowing anything about a needle or what actually happened, where do i go from here...? (thx, btw)

Sound like you're ready for a new U-joint.

But if you ever have any questions about driveshafts and how they are installed or how they work/function check the links in this Tech tip: http://www.stovebolt.com/techtips/driveline/setup/index.html

Grigg

you wouldn't have seen the needles unless you looked inside of the cap before you put it back on. the needles are just held in there by grease. sometimes one may pull out just a bit when you remove a cap and when you go to replace the cap and the cross or end of that little shaft will push the needle sideways under the end of the cap (dropped needle) and then you force the cap on and there isn't really any room there for that needle and causes you problems or it doesn't sit all the way into the yoke and you tighten up the little ubolts that hold it together and that causes your problems.
as Grigg says you need a new ujoint. don't drop any needles either installing it in the shaft or unto the rear flange. and don't put the d/shaft tubing in the vise.
it happens to just about everyone and iyt is marked up to experience
have a good one as it is not serious
ron
remember which way the zerk fitting faces when you install the cross in the shaft

well, when the cap dropped off the U-Joint, it was on the topside of the driveshaft--away from me. so, i couldnt see it.

i just reached down, grabbed the U-Joint cap and pushed it back on.

however, if the zirk fitting's "direction" is critical, i'm back to wondering if i should just rotate the driveshaft 90 degrees and rebolt/test drive it a few times to see if the driveshaft's balance/rotational position is critical.

any final thoughts? (should i rotate/rebolt the driveshaft or just change the U-Joint?)

thanks for everyone's input,

mechttu
Houston, TX

Change the u-joint. The zirk only changes when you change the u-joint.

Removing the driveshaft flange or the U-bolts and reattaching it in a different position makes no difference.

Having the U-joints on both ends of the same shaft lined up with each other makes all the difference. If you had a good shaft and both ends are welded on then you couldn't have messed that up.
If you have a slip joint in the shaft or a spline of some sort between the two U-joints there is a chance you slipped it together in the wrong position.
The Spicer manuals in the the tech tip explain why this orientation is important (and the few occasions when a different angle is advisable).

So far from your description sounds like you have a bad U-joint, it's easy to do.. We've all probably done it at least once.
Do you have a picture of the shaft?

Grigg

grigg - if the joint wasn't taken out completely, there's no way to mis-align it relative to the other end. bec it can only go back in two ways, 180degrees difference, but either way would still put it back in alignment with the other end. no?

he does have a 700r4 so there is no slip yokes between the joints. all that he has to do is install a new ujoint and put it back in. there would be no wrong way to put the shaft back in. it can be put in one way or 180 degrees and it makes no difference in this application
ron

That's what I'm thinking, but wasn't going to eliminate a slip yoke and or joint phasing problem without seeing a picture or a good description of what he has.

For example, both of these shafts could be assembled wrong http://www.stovebolt.com/techtips/driveline/setup/a.jpg
But one with yokes welded on each end can not be assembled wrong... (unless welded together wrong to start with)

Grigg

A good U joint will not make a "thunk" when rotated. They are a completely snug fit and shouldn't show any play at all.

right and he said that he had it made so if a pro made it, it should be in alignment," you hope".
ron

Was anything else taken apart? Are you sure the the vibration is from the driveshaft. I am still wondering why it was taken out in the first place. Is the tailshaft bushing in the transmission still intact? Was the pinion nut monkeyed with when the shaft was out?

I am still wondering why it was taken out in the first place

that was also my question cren, but he didn't answer

if you have a 2-piece driveshaft, then you have a phasing problem unless you shortened a 1-piece, then you may have a phasing problem only if you shortened it.

it has already been concluded that it is a one piece d/s
ron

rednate,

"why was it removed?"
at the time, i needed to pull the driveshaft out of my tranny's tail housing in order to install new speedo gears (so my speedo would read correctly).

i realize now that i shouldn't have been messing with the u-joint to remove the driveshaft, but this was my first time under there and i wasnt sure HOW to get my driveshaft out to access my tranny's tailhousing.

call it inexperience...

PROBLEM SOLVED!

the source of the problem was several needles had come loose when i dropped the old U-Joint Cap.

I bought a new U-Joint at a local auto parts store (with lifetime warranty) for $13.99 + tax.

after i installed it, no more vibrations were present at 40-65 mph.

BIG TIME KUDOS to everyone who chimed in.
I truly appreciate your help.

mechttu
Houston, TX

ah - good go

i've found my inexperience to be a gggrrrrr! but good teacher esp when the more experienced are around to ask

I concure with most of the info posted by others.
If you removed the drive shaft as an assembly by simply unbolting it from the differential yoke at the 2 U bolts lowering it and sliding it out of the rear of the tranny housing and did not remove the universal joints from the drive shaft. I can't imagine any reason for completely removing a front or rear u joint just to drop a drive shaft for a quick-ee speed-o gear swap? Chances are, the shaft assembly balance is not altered and the shaft can be re-intalled without regard to it's "clocking" to the rear yoke.(180 degrees either position)
Next, drive shafts are in fact balanced and generally have small steel weights welded along their surface. Generally, shafts are balanced at a machine shop without the universal joints attached. Unless the shaft has been bent, twisted, crushed, shortened, lengthend or lost it's weights, or has a thick layer of undercoating applied to one side it will remain balanced.
I would suspect based upon your information provided that the vibration that magically occured after removing the shaft is in fact a problem with the universal joint at the point of disconnect. You have either not ensured that the u joint bearing caps were not properly seated in the yoke journal or you have installed the bearing cap/s with missing or misplaced needle bearings. Re-check the u joint at the point of disconnect make sure all bearings are in place and the u joint caps seat in the indent of the differential yoke fully. Make sure to torque the u bolts evenly and to the specs.