Time for another driveshaft?

[Motorhead350]

I changed the U-Joints in the car a few weeks back. Upon install, I felt a ton of vibration, especially past.... the speed limit. I found out I needed the driveshaft balanced. I took it to a shop and they told me the U-Joints were not in properly, so it was hammered in properly (all the way) and they added weights to it for me. There was no promise this would fix the issue because like an idiot, I did not mark anything.

So after I installed it for the second time, a lot of vibration has gone away, but when I go above... lets say 65 the vibration is back, but it's pretty minimal. Still, it sounds like I am next to someone with an annoying subwoffer.

Is it possible the yolks are on the wrong sides or did I ruin this thing? With the u-joints off, the driveshaft looks the same on both ends.

Any and all help appreciated, even insults.

Thank you.

[whitey]

some stuff is better left to the professionals, i cant imagine that its ruined, but it might need more work done to it to make it work properly. good luck.

[RoyLPita]

Take the driveshaft off from the flange and reattach it after a 1/4 turn. Maybe that would cure your vibration issue.

[Motorhead350]

Take the driveshaft off from the flange and reattach it after a 1/4 turn. Maybe that would cure your vibration issue.

I will give that a try.

Thank you.

[tbone]

Maybe the u joints were ruined by not being in all the way the first time.

[Comin' in Hot]

take it to get it balanced, its the only way you are going to fix it.

[Stranger in the Black Sedan]

You can definitely ruin an aluminum driveshaft by not installing the U joints properly, it's actually pretty easy to do because the caps are so much harder than the aluminum bores. What kind if tools and method did you use to change the caps? If you attacked a soft aluminum driveshaft with a hammer to change the U joints, you probably ruined it. You really need to use a press w/ a mandrel, or a portable U joint/ball joint press, to handle U joints on an aluminum shaft. If you abuse it like a steel driveshaft and bang away on it against concrete you might not have good results. You'd have to check the end play on each cross shaft of the joints using a dial indicator. If you have end play you can't get rid of, you probably boogered up the snap ring lands on the shaft.

[lifespeed]

Normally a re-balance is not required after changing U-joints. To be brutally honest, you have probably screwed something up.

If you're chasing after a clunk in the rear there are other places to look as well: ring and pinion backlash in a worn rear end, and control arm bushing wear. Did you look at these? They're probably more likely an issue than the u-joints.

Also consider that it is sometimes worth paying a good mechanic to do work, rather than damaging expensive parts yourself. A wise engine machinist I once knew said "There's never enough money to do it right, but there is always money to do it over."

[Motorhead350]

Yeah I think I managed to break it.

I have yet to try the quarter turn, but I will soon.

[Motorhead350]

I think I need another.

I keep forgetting, what CV model years have the driveshaft that is good all the way to top end?

Thanks!

[larryo340]

MMC Police shaft that came in the 99-00 P71's, but hard to find.

http://i299.photobucket.com/albums/mm288/larryo340/My%20Marauder/32e5a38a4ce1c18dd5f688890bdeff a2_zpscaea6095.jpg

[fastblackmerc]

Dom, a drive shaft is one item you can source from a recycle yard.

[Motorhead350]

Ok thank you.

[vegasmarauder]

Just find a CVPI aluminum one from 99 up. It may not be a MMX but unless you have gears and plan on 105-110MPH plus sustained driving it will do. It is the same shaft as the MM except they didn't put the damper on the front because a little vibration in a CVPI was no big deal. If your damper front yoke is not bent they can use it on the new shaft. The color stripe code on the CVPI aluminum non-MMX is Pink/Green/Green, (same as the MM). MMX is Pink/Green/Blue.

Have a drivceshaft shop put it together and balance it. The ears on the aluminum ones are esy to bend and impossible to fix once bent (which comes from hammering out the joints with a socket and floor).

They get $35 out here in the pickapart yards for the CVPI non-MMX shafts.

A vibrating shaft is going to destroy your transmission output shaft bushing and seal and possibly the rear case output shaft bushing and then we will have another thread about how your trans is messed up now. Don't delay fixing the problem.

[Motorhead350]

Wow ok. Better get on it asap!

[nh muscle]

Dom I can send you pics if you need them

Sent from my HTC6435LVW using Tapatalk

[Motorhead350]

Its ok. I found the cop car one that is good all the way to top end. I pick it up monday.

Thank you though.