Elvis is leaving the building

[jmsaunders]

Monday night I ran up to Clarksville from Lebanon (about a 200 - 220 mile round trip). On the way down the 72 was shaking BAD around 65 and would sorta begin to clear back up if I could get up to around 70 (yes I'm running the original inline 6 so that was generally going down hill with a strong tail wind lol). So I creeped down the highway doing 55 - 60 and took the truck straight to a tire shop and had the tires balanced. According to them they were WAY out of balance.
Problem solved I thought. Ran to my brothers and did some work on my nephews car. Jumped back on the interstate to come home and was having the same problem. It wasn't as bad but still definately there.
Did some snooping around the forum and the internet and came up with some ideas. I cleaned a lot of the 40 odd years of built up grease and dirt off the suspension. Greased my ball joints and u joints. Today I put her back on the interstate to see if she still Shakes, rattles and rolls lol. Well yes she does. But it is very slight. Later today I'm going to change the front shocks. If that doesn't fix it then next I'll take her in for an alignment. After that I'll move to the back shocks. Hopefully that'll get the prob completely fixed.
Yes the problem is still there but I'm just happy that most of it has been fixed with 'basic' maintenance

[JRANGER]

good job!!! I would of been clue less lol

[leftcoast66]

Have you thought about checking the balance on the driveshaft? That can cause a shake as well. Nice work on rebuilding everything.

[CC69Rat]

Is the shaking in the steering wheel, or does it feel like it's coming from the underside of the truck? Is this truck lowered? Is it a LWB or SWB ?

I think I know what the problem is. .. just need more information.

[jmsaunders]

A little bit of it feels like its in the steering wheel. I think that is coming from the loose play in the column but I could be wrong. The majority of it feels like its coming from the wheels or under the bed. I haven't tried getting the drive shaft balanced but may give that a shot now that you mention it.

As for the info on the truck its a 72 LWB, 250/350. It does have the 2 piece drive shaft. Its stock height as best I can tell unless the previous owner lowered it but it doesn't appear to have been. It does sit a little low in my opinion but I think that's from saggy springs (yes they are on the replacement list ) But if you have other ideas of what I should check I'll happily check to see if that gets the shake completely out of the truck.

[CC69Rat]

Some of the other guys do too I'm sure, but I hang out on this site alot.

http://www.nastyz28.com/forum/showthread.php?p=2468039

Check out this article on the Pinion angle. What happens is this, when the truck is lowered, the springs change blocks added etc. The Axle orientation in the truck barely changes.

If you take a look at the front pinion, where your driveshaft connects to your rear end housing. This is what I'm referring to. And the fact you have a two piece driveshaft just complicates it a little more for you. (you have more angles to contend with) Not the end of the world, but you'll see what I mean.

All the angles where the trans tailshaft meets the first part of the driveshaft (A) then where driveshaft 1 meets driveshaft 2 (B) and where driveshaft 2 meets the rear end housing (C) You want these angles to be fairly close in relation. this article will explain it much better than I could type it all out.

The way I think about it is a jump rope. When it swings, the top angle of each handle causes a shorter distance on the inside than it does the outside. Make sense? So when the driveshaft spins (as you speed up) the vibes get stronger and stronger. Slow down and they go away.

It really sounds like (to me) if you put some pinion angle shims under your rear axle housing and 'nose down' the (C) point I mentioned above it would really help you. I would almost bet the yoke on the rear end housing is pointing slightly 'up' in relation to the (C) driveshaft.

This is really common in lowered trucks, and lifted Jeeps (I have been around the Jeeps too)

Just for example if you put a couple washers under the tailshaft of the transmission and the mount to raise it up just a hair, it might take 1 deg of angle out of your driveshaft in relation to point (B)

You don't want these completely 'Zero'ed' out .. but 1deg or two at the junctions will really help with high speed vibes.

I dropped an S10 ext cab and it has the carrier bearing in it too. I had t ouse a kit that moved the tailshaft of the trans and the carrier bearing to make this angle straight.

Here's their kit. I know this is S10 stuff we're talking about .. but this will explain the situation very well.

http://www.jagsthatrun.com/Pages/Par...aft-Align.html

Get this right and your truck will ride sooo much better. I promise.

[jmsaunders]

Thanks CC69RAT. I don't have an angle finder but know they sell them at Harbor Freight for about $5 and will pick one up. I do know from just crawling under the truck that the rear end pinion does seem to angle up instead of down or level so it's most likly off. I guess that mean's I need to get new coils sooner than later as I'd just have to set it again if the ones on there are saggy as I believe they are lol.