Truck starts to shake when going 25-30mph???

[wldcat10]

Ok I have a 2 problems. (#1) I was driving my '70 lwb c/10 on saturday and it started to shake when I was going about 25-30mph. I pulled over and couldn't really figure it out what was wrong? So I got back in and did the same thing again around 25-30mph, if I speed up it kind of lets off and if I slow down the shaking slowly starts to fade out. Not sure what it could be? Could it be that my shocks need replacing? (#2) Noticed that a had a small spot on the concrete where something was leaking under my truck. It was a very small leak from the speedometer cable was. So I tightened it and it stopped. Now my speedometer needle jumps back and forth between 30-50mph on the gauge. What can I do/adjust so that it doesnt leak and I dont have the speedometer needle jumping all over the place. Any help is appreciated, thanks!!!

[dcasalena]

hopefully the shake is something as simple as a wheel out of balance. Maybe threw one of your balance weights?

[wldcat10]

I am going to be getting an alignment and new tires hopefully this friday. Could it be shaking like that because it needs an alignment?
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[bajaracing]

if not the wheels, check the driveshaft support (usually it's a vibrating shake) just an idea..

[Lee H]

Shaking could be caused by several things including wheel balance, tire defects, worn out suspension components, mis-adjusted wheel bearings, etc, or any combo of. Tell the alignment shop about the shaking. They will do an inspection and advise of problems.

[JOHNORO]

I agree that you might have lost a wheel weight.
You might also check your tires to see if any of them have separated
just run your hand along the top of the tire to see if you feel a Lump.

[wldcat10]

When a buy new tires and get the alignment, do they check/replace wheel weights if needed?
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[JOHNORO]

Most shops that mount your tires will also balance them.
(but there usually is an additional fee)

[C low]

my 67 would shake at 30 to 40 having a few trucks with a two piece drivelines i knew it was the carrier berring the berings are usally good but the rubber that supports them rots good luck hope this helps

[justtime520]

Hey bro it sounds like your driveshaft. I would pick up some new u joints. I got mine from oriellys on grant and silverbell. They always have them in stock. Put them in and made sure the drive shaft was sitting right on the carrier bearing. After doing that, no more shake.

[wldcat10]

I'm gonna go see if its the wheel weight that's missing first by taking it in to get them balanced after I get my new tires. I hope that's all it is!
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[justtime520]

Hey bro also check out your hole front end and look at all the boots. wait is it shaking from the front or rear.

[wldcat10]

Feels like its shaking from the front passenger side.
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[justtime520]

I wonder if it is a bearing.

[dcasalena]

All these suggestions are good, but I'd think they would cause a constant vibration. Except my original thought, wheel balance, which tends to only happen at certain speeds. What that speed is can vary, but is worse at some certain "resonant" rotation velocity of the misbalanced wheel.
Most tire shops mount and balance new tires for "free", which means they already included it in the cost of the tire(s). Alignment usually cost some bucks though.
Good luck1

[wldcat10]

Yeah might be that the tires need to be balanced. Since I'm getting new tires this week I'll be getting them balanced too, hopefully thats what it takes. I also need an alignment so that will be another thing to cross off the checklist, thanks to everyone who replied!

[vexvader]

Originally Posted by justtime520

Hey bro it sounds like your driveshaft. I would pick up some new u joints. I got mine from oriellys on grant and silverbell. They always have them in stock. Put them in and made sure the drive shaft was sitting right on the carrier bearing. After doing that, no more shake.

Yep! I have a 70 LWB and that exact thing happened to me. I would bet that it on of these tow things. Wheel out of balance or drive shaft bearing.

Let us know when you track it down.

Vex
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[leddzepp]

check your u-joints. i had the same exact problem at 25-30 mph. and 2 u-joints were worn.
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[CC69Rat]

Is this a shake you're feeling in the steering wheel? or more in the seat, like it's coming from underneath the truck?

Is it like a humming vibration, or a physical shake (the steering wheel moves when it shakes) . ? coming from the RH Front, I'm leaning away from the drive shaft, just my .02.

Have you hit any big pot holes on that side recently? Does it make a clunking sound when you turn to the left at 20-30 mph.. going up / down a freeway ramp or somehting?

[cdowns]

i'd check to see if the lugnuts are tight

[wldcat10]

Originally Posted by CC69Rat

Is this a shake you're feeling in the steering wheel? or more in the seat, like it's coming from underneath the truck?

Is it like a humming vibration, or a physical shake (the steering wheel moves when it shakes) . ? coming from the RH Front, I'm leaning away from the drive shaft, just my .02.

Have you hit any big pot holes on that side recently? Does it make a clunking sound when you turn to the left at 20-30 mph.. going up / down a freeway ramp or somehting?

The shake is more in the seat like it coming from under the truck. no humming sound that I've noticed? steering wheel is normal from what I've noticed (no power steering). I have not hit any holes or anything like that. and no clunking sound when turning.

[BIGBLU 72]

My vote goes U joints! my Jimmy did this till i swapped them out! shook sooo hard that it would move my rear view mirror, then i speed up or slow down and it goes away

[CC69Rat]

I thought you mentioned Front Pass side ? Yes, if it's coming from under the seat, definately in the drive shaft, U-Joints, Carrier Bearing, or Pinion angle. Is the truck lowered?

[brad_man_72]

if it ends up being your drivesaft. Take both pieces of your driveshaft to a shop that works with drivelines. They will have the equipment and theknowlede to fix your driveshaft right, and they will be able to ballance the shaft as an assembly.

I've seen many people who call themselves mechanics mess up a driveline job because they don't have a clue how it works. It's not just a metal stick between the trans and rear end.

[wldcat10]

Originally Posted by CC69Rat

I thought you mentioned Front Pass side ? Yes, if it's coming from under the seat, definately in the drive shaft, U-Joints, Carrier Bearing, or Pinion angle. Is the truck lowered?

Yes I did say it felt like it was coming from the front passenger side. I just said I feel the shaking more in the seat than I do the steering wheel like you had asked. The truck is not lowered its all stock.