Anyone have a powr lok in the rear end in there truck and had an issue with severe shake and possibly axle wrap at about 40-50km/h. Its starts at about 40 kms and you you can feel it gradually shimmy on what almost feels like the front end until it shakes the whole truck apart. Never had any problems when I had it on road last but now it has a dana 60 front with crossover which runs very smooth even during the shake issue so steering doesn't seem to be the issue. The only other thing is I installed a power locker in the rear and it might possibly be giving me axle wrap. I first thought it might have been my detroit locker in the front because my hubs were locked but no driveshaft was in but no it wasn't that either... My driveline is tight and angles on ujoints are not steep and havn't been changed. I have a 4 inch block under the rear springs and come to think of it I have a shackle flip to. The box is full of scrap steel and junk too is this too much for the shackle flip and the reason for the shake?? I've heard shackle flips lowers the towing ability. What do you guys think??

 

Your HP60, is it kingpin or does it have ball joints?? I don't have any experience with flipped shackles, but I wouldn't think they are your problem?
after all the front shackles hang down(just pondering). I have experienced what bronco owners call the death shake, when the track arm bushing get loose. let use know what you find .

Thanks RW

 

yeah its a kingpin frontend. I have a track bar with leaf springs and I ran it with and without. No difference. I need a camera on my driveline while its happening to see whats going on. Maybe I'll just tow my brother beside me on a skateboard...lol

 

Front ends looks good. I have asked before, but I have to ask again. Does the driver side spring hit he drag link, or pitman arm during full spring compression? Mine has enough flex to kill that, and I am still a little concerned that this drop pitman arm is gonna hit.
Back to the topic.
It is entirely possible that the Power-Loc limited slip is chattering, but probably not at the speeds your describe. Your block back there is not the contributing factor. Axle wrap is not the cause of this at the speeds you mentioned. You would encounter much more of a problem during acceleration from a dead stop if this were the case.
Your shackle flip is also not a problem, unless,,,,,the shackle angle is wrong. If the shackle points foward, you will have an issue, and a rough ride. I do not recall how you did you shackle flip, but if a stock habger was used, you wil have to move it foward to obtain the proper angle.
Much discussion has been made with regards to limited weight capacities and shackle flips, and I have a difficult time believeing this. I tow some incredible weight with my 74 and I run a shackle flip. Never have I had a problem, nor have i bent a shackle. I side load the snot out of them without a single failure.
I tow my trailer, and have had other full size F250 trucks on top of it, without a single problem. i do not believe the statement that weight capacities are limited by the shackle configuration.
Alight, just by design there are limiting factors, but I doubt that you have reached that threshhold.
To make things real simple, we should look at the basics;
The driveline ange should be alright, but what about driveline phasing? Is it in phase?
Is it too far extended? Is there enough penetration in the splines?
Are the splines greased, and are they in good condition. Worn splines can also cause this problem.
Was friction modifier suggested for your LS rear? Even though it is gear operated, it still has clutches. This is a two piece carrier right?
Are you absolutely sure that "caster" is not a problem? I believe I spy a pretty long set of front shackles, and a rather large wedge, or block under the front spring pack.

 

Sounds like typical big tire shake. Did you load the tires with bb's ? Did you shim the king pins ? Did you put the 2 tires with the least amount of runout on the front ?

 

All really good suggestions.My suspension is all the same as I had before with the pinion shim under the front and shackles. I have a spring hanger drop as well to compinsate for the longer shackles. That wasn't my problem before though. 75f350 my draglink is actually very close to my spring on the pass. side and I'm actually changing to a stock pitman arm today when my tie rod end comes in to make the angle steeper for clearance over the spring. It was actually slightly rubbing when turned right or left can't recall which. the thing is though the steering seems to be ok while it shakes. This could very well be my issue though!!

 

Limited slip in the carrier is a good idea as well. just thought these carriers didn't need an additive as they were a locker.Yes it is a two peice carrier. as for shims under king pin caps I've heard of this for larger tires but thought i'd run it before I did that. It two 7/8 washeres under the cap right? Do you guys have experience doing this and what are the results before and after.

 

I have installed shims in my king oin caps, and it worked well. Beware not to put shims that are too think, or you will bind the springs, and this is worse than not having enough tension.
Too tight and this will happen:
Image of Problems with big tires and king pins - Photobucket - Video and Image Hosting
The better fix, is to cut the original steering arm off, and clean it up so you can use it as a new KP cap. It is much stronger than the stamped steel unit.
Looks like this after:
Image of Final KP fix - Photobucket - Video and Image Hosting
I have a few other pics in my photobucket that you can look at. Some washers do not fit all the way to the bottom (actually top) of the KP retainer, so be careful that you size your shims correctly.
Easy fix, but this problem typically results in a steering wheel wobble.
The Dana Power-lok is still a Limited slip, despite the name, has imitations, and while it is a good LS, it is not a true locker. It still has friction plates, and I believe they recommend 1 bottle of GM LS additive.
Since you have driven the truck, and this is the new variable, you may just add some friction modifier, and see if that cures your problem.

 

what is loading the tires with bb's??

 

So loading the tires with bb's is exactly what it is duh. I was thinking bb's stood for something. I did notice tonite one of my back tires has a pretty good wobble to it compared to the one beside it. I put axle stands under it and let'r run in 4th at pretty high RPM (started to wobble pretty good). With the tires of it ran smooth then again with tires back on but in switched postions to make sure it was tire it wobbled again. So putting bb's in the tire...how much and does this cure a minor death wobble. thanks guys