Driveline Vibration

[MrFiveOh]

Whats your exhaust setup? all secure?

[philo_beddoe]

Factory config. single exhaust. Not touching anything. I wish it were that!

Thanks for the reply though. I have a feeling i dont get much replys on this problem, either folks are sick of the thread or its just too difficult to pinpoint. I should learn a lot this week though. Will post results.

[SkinnyG]

~I~ am NOT sick of this thread.  I am wanting to ride your coat tails.  WHATEVER HAPPENS - make sure you post the solution on here.  I hate threads on exactly what I need info on, only to find the thread left dangling with no solution.

I notice mine feels like it will come back or go away if I turn a corner.  This would indicate a bent or imbalanced wheel to me, but I have checked and re-balanced my wheels.  Problem is still there with my winter wheels and tires too.

I ~did~ balance my brake drums - one needed 5oz of weight - but the sticky weights fell off this summer.  I will machine the heavy lip down to balance it this fall, but I'm not convinced that's the problem.

My exhaust is very tight, but still compliant.  Using typical universal hangars at the back of the cab and at the tail pipes.

I've raised the tail of the transmission, and shimmed the every which way but fixed on the diff, no solution.

I had the front u-joint (a brand new "Precision" joint) go south in a hurry - I replaced it with a Spicer which made a difference.  The rear still seems tight, but I have a Spicer in the glove box for when I'm feeling frisky.

I have flipped the driveshaft 180°, and I've swapped pinion yolks to no avail.

I've tried different flexplate (broke the factory one), rebuilt the entire back axle (all new everything), and recently rebuilt the trans (it popped).

I ~do~ have poly motor, trans, cab, and suspension mounts, so I certainly will feel a whole lot more.

[Irish_Alley]

im not tired of it but i think youre on the right trail now and its the only thing left. so im just waiting to hear you say "fixed"

[MrFiveOh]

Factory config. single exhaust. Not touching anything. I wish it were that!

Thanks for the reply though. I have a feeling i dont get much replys on this problem, either folks are sick of the thread or its just too difficult to pinpoint. I should learn a lot this week though. Will post results.

Im just as curious as you are, issues like this are the reason i like groups like this. I like troubleshooting and eventually someone down the line will have the same issue. Obviously it isnt an issue we have dealt with before based on process of elimination, so im really curious as to what it is.

[philo_beddoe]

im not tired of it but i think youre on the right trail now and its the only thing left. so im just waiting to hear you say "fixed"

Well thanks for the encouragment! Ya know irish, your right...everything has been addressed, except what lies behind the rear ujoint and between the rear wheels. I will have a long conversation with the shop tomorrow. I'm not going to rule out anything, but there is strong evidence as to what it is NOT. I never thought of unbalanced drums or raising tail end of tranny. I will certainly mention that.

I will keep this thread updated. And if and when solved, all will know. I will include a summary of the problem and all the trials right to the end.

I have a strange feeling Vile Z. will have his hands on it last.

[philo_beddoe]

Well stopped at shop this morning and took the mechanic for a ride. I could hardly feel the vibe myself it was so smooth. Figures!! The mechanic said he really needed to feel it to get an idea where to start. Sounded very knowledgable and professional. Anyway, i wonder if having a passenger does something, he was a little heavy set. Maybe theres a pattern, problem is, i never have any passengers. But i do have sandbags to simulate. Could something be off-centered or not level??

[zieg85]

By adding weight it will change the driveshaft angle

[philo_beddoe]

Perhaps its off a little, how do i physically adjust the angle?

I know Vile is usually against "stacking washers" lol

[zieg85]

I am merely suggestion that if weight squats the truck some the angle of the driveshaft changes.  If the vibration changes or is eliminated that is a clue.  Stock height 2 wheel drives shouldn't matter the angle within reason.

[philo_beddoe]

Before the new engine, i had a new tranny mount installed.  But, i cant remember if i had this vibe before that. The old engine vibe was so bad that it superceded this one.

How about 1 or 2 rubber washers on one side of the tranny mount? Just to see? I'm tempted.

[philo_beddoe]

STOP THE PRESS!!!!

Attached is a pic of my simulated heavy passenger i had this morning. 4-60 pound sand bags, 240 lbs.

Note: no offence if you weigh 240 or more.

Anyway...took a long drive and it felt like it did this morning, real smooth! I'm too exited to think. Someone tell me whats going on? What do i need to adjust? Perhaps a different size tranny mount? Stack some washes somewhere??? Help, and thanks!



Of course....i'm going to drive around with my simulated passenger for a few days. I've been bamboozled before!

[MrFiveOh]

Before the new engine, i had a new tranny mount installed.  But, i cant remember if i had this vibe before that. The old engine vibe was so bad that it superceded this one.

How anout 1 or 2 rubber washers on one side of the tranny mount? Just to see? I'm tempted.

Maaaaan, i said trans mount the very first time... lol

[philo_beddoe]

Nice job 5-oh!!  Lets see what a few others say!

VILE!!!  "Oh where could he be?"

[Irish_Alley]

See how much of the slip yoke covers the output shaft of the trans before and after the added weight.