The Stovebolt Site Forums The Shop Area Engine Shop shake at 40 mph and above...

tried the serach and didn't come up with anything like what I have.
at 40+ the 53 gmc 228, 6cyl, 1bbl 4:10 has a bad vibration. not sure if it's engine, drivetrain or rear end. i know the rearend has quite a bit of play in it when i jack up the pumpkin and turn one of the wheels back and forth. those old gears might need adjusting but i've heard that's not for the faint of heart or inexperienced.
what can i do to troubleshoot the source and what are some suggestions for each of the 3 locations it could be once i narrow it down please?
btw, i have new radials balanced corrrectly with good straight 6 lug steel wheels and the alignment is correct.
thanks
tony

Sitting still rev up the engine in neutral & see if you get the vibration. If it,s in the engine or clutch you will feel it. It,s not likely to be the trans. or rear end. If you still have the closed drive shaft it probably is the u-joint. Drive line vibrations are higher pitched than wheel vibrations because it is going around 4 times as fast.

i still have the torque tube. i think the whole truck is original. anyway, i was told the ujoint was replace by PO, but i don't even see one, much less know how to check it for play. i'll check the manual. thanks very much wrenchbender for the info.
tony

Where do you feel the vibration?
If it is felt in the steering wheel more that cab parts, it is front wheels. If you feel it in the cab floor stronger than other places, it may be rear wheel balance.

Normally, driveline vibrations, especially u-joints, will change intensity with acceleration, cruise or trailing throttle.

Post back with more info after a test drive.

kenc, i have new radials and wheels on the rear and i'm think they balanced them corrrectly. the vibration seems to be more intense at cruise and trailing and eases off under acceleration. it is also present with the trans in neutral and the clutch out (foot off the pedal). it seems to clear up the instant i hit the brakes although that could be because i'm bringing the speed under 40 and that don't take much cause i don't drive more than 50. i'm pretty sure i'm feeling it in my feet and also in the steering wheel and gear shift lever. i dont' feel it in the driveway revving the engine in neutral, not moving.
what is it?

Old Blue,

My truck shook like a paint shaker until I put new radials on. Since you already them on back, I would put them on front. If your truck was ever stored, the tires will go out of round. I have seen it on 04 and 05 cars that have been on the lot but not driven for a few months. They shake like crazy.

Also check your king pins and bearings. But start with the tires/rims. If you are running stock style rims, make sure they are straight. I had one rim that was all bent up. My problem was up front. Worn or out of adjustment front end parts made the bad tires even worse.

Since you say it tends to happen at a specific speed, my first thought is tires.

I'd think if it were anything else you'd notice the vibration at 20MPH or 30MPH.. maybe not as intense, but you'd notice it.

I had a car once that just out of the blue would start rattlin' like it was going to fall apart right at 45MPH.. you could drive all day at 44MPH and it was smooth as silk.. but at 45MPH, it would rattle your teeth out of their sockets.

Turned out to simply be a weight had come off and put the passenger side tire out of balance.

If it was me, i'd take all 4 tires off and have them balanced.

I've been away for a couple of days, sorry for the delayed response.

I would swap tires front to rear and see if that changes the vibration. If it does, take the others advise and check, replace or balance tires.

If not, then you know it isn't tires, engine or clutch (since it doesn't do it reving sitting still).

Then check the u-joint, it is possible that it is not properly seated in the trans yoke since the PO replaced it, or worn due to lack of lubricatiion when it was replaced.

its a high pitched harmonic vibration; actually deafens you at a certain road speed inside the cab. its like some sort of harmonic or resonance. it could be engine, clutch or driveline as the frequency is so high and i bet it is something involving that torque tube/ujoing setup.
i'll report back when i get ready to tear into the transmission/tube for help as i know nothing about these enclosed bearings and ujoints.

thanks for all your help
tony

This is a long shot but the front bshing in the torque tube could have gone oval shaped. I had vibration at 45 mph and didn't know why. For another reason I put an Okie bushing/seal in the TT and the vibration went away. My front bushing which I had to pull out to install the Okie assy was worn oval shaped. As I say it is a long shot and I hope you find out what it is before you pull the TT apart.

about 6 or 7 yrs ago I had a '70 ford f-100 that vibrated real bad at around 50 to about 60-65...I got the drive shafts balanced and new u joints at a drive line place in Jacksonville and it was smooth all across the speed ranges after that...

I'd be suspicious of the front bushing in the torque-tube...

These are notorious for going bad in Chevy cars and trucks with torque-tubes...

I had a '50 Chevy Fleetline sedan with a bad driveshaft bushing (4.10 rear too!)...the vibration would appear at about 40-45 mph, be at its worst around 50-55mph, and would begin to lessen around 60-65 mph (but then the 216 was getting very unhappy !). The vibration would also vary with slight changes in pressure on the accelerator.

My '54 Chevy 3/4 ton (open driveshaft) had a similar vibration that turned-out to be a bad rear bushing in the tranny...

At any rate, I think what you're feeling is a drive shaft vibration...check out "Oakie bushings" in our various Stovebolt vendors' catalogs and see what you find...


Good luck !

thanks frank54 and all others. i'm convinced it's either a u-joint or the torque tube bushing from what you all are telling me. if anyone has any hints, tips, tricks to pass along that make the procedure of getting into the tube and replacing this seal easier than the manual, i'd appreciate it. the manual is good, but doesn't always take the most direct approach to my particular problems.
thanks again

I know this is an old thread but I'm having the same problem, mine starts about 45 or so, was the solution ever for sure determined

I wonder if running it with the rear on jack stands would give you some clues. If you do that I would suggest putting the jack stands under the axle in order to keep the driveline angle as close to normal as possible.