70hemicuda

I have done everything to try and get rid of these vibes. I did a hack n tap sye and shimmed the rear axle so its pretty much perfect. brand new tires that are balanced and an alignment done. As far as i know u joints are solid. I really dont know what do from this point on. Help would great. Its great until I hit 60-65. Then the shakes come on. Any ideas?

Tony_SS

Have another set of wheels and tires you could try out?

What is your working angle at the pinion?

freegdr

High speed balanced or bubble balanced ? Drive train vibes are usualy come on at lower speeds and stay there. Vibes in steering wheel ?

70hemicuda

I originally thought my old tires were out of balance but these are brand new and i am getting the same vibes. I dont have any other tires to try out.

Tony_SS

This is why its never a good idea to lift and swap wheels and tires at the same time...it makes it that much harder.

See if you can borrow a sent of balanced wheels and tires that are confirmed good. I would start there. Even new tires can have runout..

Also you never said your working angle at the pinion.. you need to know that to know it is shimmed correctly.

70hemicuda

I have had the lift on for about a year now, I got the tires cause my old ones were bald and also hoped the new ones would have fixed my vibes. i dont know my pinion angle exactly but the rear axle yoke is straight with the driveshaft.

Tony_SS

Instead of eyeing it, determine your working angle at the pinion and let us know what it is. It should be 1-3º.

If you dont think its the tires, that is the next best place...but vibes in that ranges are usually tires I think. Did vibes change at all from the old to new tires?

70hemicuda

how would i measure it correctly? protractor? and the vibes got a little bit better, but nothing that was major and pointed to the tires

Tony_SS

use a simple angle finder gauge or a free angle app on a smart phone.

Measure driveshaft angle and then pinion angle, subtract the two. That is your working angle. Mine looks straight but is actually 7º. It should be 1-3º. Go to tom woods website and do some reading.. its good info.

70hemicuda

measured them both with a finder on my phone. I got a 5-6 degree difference. But im not sure if i did it right. I measured the ds in the middle and the Pinion angle on like the arms of it, where it hold the u joint. is that a good place to measure?

Tony_SS

No, on the back of the differential.. there are 2 bolts on the left hand side that are top and bottom of each other. Use those

freegdr

Pics can really help in giving you the correct advice on this...

SteveMongr

Front wheel bearing maybe? Or front pinion angle not adjusted properly when lift was done?

Tony_SS

How can you adjust the front pinion angle? Never heard of that one.

SteveMongr

With adjustable control arms. I use lower arms to set wheelbase and uppers to set the caster and pinion angle.