vibration problem

[ONEBADPNY]

ok here is the deal i just put in a new tremec 500 and new yoke with it. now at highway speeds of 60 plus i get a vibration in the drivetrain. it is more serious or just more noticeable with speed increasing. if i push the clutch in and coast it gets worse then if it is in gear. not realy noticeable to me in town driving normal. i am thinking it is just a u-joint that is causing this. maybe i did something to it putting in the new yoke. i tried spinning it 180* but nothing helped there.

 

[Daggar]

Did you happen to replace the u-joints when you pulled the DS? Only reason I ask is because pulling and reinstalling the DS seems to be the hot ticket in finding u-joints that were bad but just weren't giving any signs.

 

[HISSIN50]

A driveline shop can dynamically check the rotating assembly balance (you have a lot of new stuff going on - might be tough to figure out which item exactly is at fault).

Good luck.

 

[89MustangGX]

I would suspect the u-joint as well.

 

[slow93]

I would suspect the u-joint as well.

i dont mean to jack the thread,but will a u-joint cause a vibration while accelerating and then smooth out??

 

[89MustangGX]

i dont mean to jack the thread,but will a u-joint cause a vibration while accelerating and then smooth out??

I believe that's a common symptom. I heard once that the rear u-joints will cause the most vibration while the fronts will make the most noise -- but not sure that it's 100% accurate. Once you get the DS off, if they're THAT bad, it will be easy to see. They're fairly cheap and easy to do, so if one is bad, I'd probably do both.

 

[HISSIN50]

in my experience fronts need to be replaced about half as often as rears (U-joints).

I agree with Adam. when one accelerates it loads the u-joint differently than when coasting. This can be enough to change the imbalance dynamic.

Good luck.

 

[speedytang]

IT just sounds to me you need to unbolt and rotate the shaft 180 degrees and you will be set. Common problem if you don't mark the shaft to install back in same location.

 

[ONEBADPNY]

well going to replace the u-joints tomorrow hope this does the trick. i can't afford anything else after having to buy a new tranny to replace the broken one. thanks guys

 

[ONEBADPNY]

well i changed the u-joint and nothing changed. going to try and rotate it and see if that helps. it seems maybe a little better but stilll there. sould some bad cross member bushings cause this vibration? i have a prothane tranny mount so thats good. going to have to change the clutch because it got really really stiff since the tranny change.

 

[speedytang]

Another common problem of vibration is that the pressure plate is not flat on the flywheel. If you had problems with the pressure plate and the dowel pins the clutch is not flat. I had a customer who installed a clutch themselves last week and it vibrated bad at different rpms but was fine at idle. I found that the bolts are torqued at 45 ftlbs. but the pressure plate was not flat on the flywheel. I honed the pressure plate holes out a little and it torqued up correctly and was flat against the flywheel. The vibration is gone. The dowel pins are cone shaped but he did not get it flat against the flywheel first before he bolted it down. I have found out by others that this is a common mistake and out of 10 who responded 8 had the same mistake.

 

[ONEBADPNY]

still have the vibration. rotated the driveshaft and changed the u-joints nothing. i going to try new crossmember bushings and maybe a driveshaft someday.