Bad U-joint?

Or a bad trans mount. Again - what year, make, and model???

Reply to
clare
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t at certain speeds, such as 40-45 MPH, I feel vibration if I step on the g as pedal and try to accelerate. If I let go of the gas pedal, vibration sto ps even as the truck continues to drive forward. It has gotten worse lately . I have thought a lot on what could cause it. It does not seem to be relat ed to the engine RPM. I watch the RPM vary and the vibration does not vary with it. What could it be? i

Worn suspension arm bushings caused that in my case, the upper suspension a rm bonded bushings had deteriorated to the point where there was only shred s of rubber left. The lowers still had the rubber but the bonding to the i nner sleeve was gone. I had another vehicle that still had the original fa ctory tie rod ends, these were also bonded rubber and had gone away. Only rattled at certain speeds and really didn't affect steering, somehow. The parts for these replacements were pretty cheap, had to have a heavy press t o replace the bushings. Have had to do this now on several vehicles since I tend to run them until they go to the junkyard. Upper bushings are hard to see on a lot of vehicles, hard to get to, too. Bum ball joints will do this, also, but you usually get a vague drifting feel with the steering whe n that happens. So check your suspension. Only real way I know of is to d etach the upper ball joint, get the spring out and see if there's play on a rms or ball joints. Now that I know how, I can usually do both ball joints and bushings on a Sat. Don't go for super-cheap suspension parts or you'l l get to do it again quite soon.

I've had regular Hooke's u-joints go bad with the needles rusted out and go ne, never really had any vibration at speed but had a loud clunk when shift ing into reverse, this was on an old IH Scout with a three-speed manual and 4WD. Never really caught on until I downshifted on the highway and the st ubs broke off on the cross on the front joint. Very noisy. Was my dad's t ruck when I was a teen and he plowed all winter with it. Didn't get much m aintenance in sub-zero. You should be able to check for u-joint play by ja cking up a rear wheel and twisting the drive shaft back and forth by hand.

I've also see vibration checked for by putting the vehicle on a lift with t he wheels free and running it up to speed with a mechanic looking underneat h for drivetrain vibration. It's a last resort, very dangerous, stay clear because rocks can come flying out of the tire treads. If no vibration tha t way, it's got to be suspension or front wheel bearings.

Stan

Reply to
stans4

Now that I know how, I can usually do both ball joints and bushings on a Sat. Don't go for super-cheap suspension parts or you'll get to do it again quite soon.

.......... or a front tyre issue (I just had one!)

I thought I had a wheel bearing problem in front RHS. Felt ok by hand when jacked up but made noise at, and varied with speed. I got a puncture in the RHF & the noise disappeared when the spare was fitted to the RHF. Tyre looks ok, seems to run true & is balanced. Beats me why its noisy. I've put it on the rear and don't notice any noise now.

Reply to
Glenn B

Amazing. It should have been wandering all over the road after you hit even a slight bump.

Amen to that.

I heard a Mexi-mobile (some funky old chebby) take off from a parking lot once. EEK-OOK-EEK-OOK-EEK-OOK from zero to 15mph or so. Must have driven the driver crazy. It was a pole-vaulting event waiting to happen. When front u-joints let go, it can make for spectacular crashes on the freeway.

I had a truck's rear u-joint go while I was following it once. The center flew out and hit my windshield right between my eyes. Luckily, it was spinning beneficially to the slant of the windshield, so my F-150 glass only got a shearing scratch there, no puncture. Most of it polished out. I was -really- lucky that day. A truck cross through the forehead would have kinda hurt. I avoided the drive shaft which the truck jumped over because I was in the next lane over by that time. Talk about adrenaline shakes...

Prolly ply sep in the tread area. They're easier to diagnose in the sidewall, where you can physically see them through the thinner rubber layer.

Reply to
Larry Jaques

I investigated this further. The drive shaft (prop shaft) does not appear to be loose.

The vibration seems to be related to a gear. If I drive wnd watch RPM, at around 35 MPH, the vibration starts as soon as the RPM drops, indicating a gear change. Again, it only appears when I push on gas, and seems to be further limited to that gear.

i
Reply to
Ignoramus27351

Reminded me of this video:

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As a kid I remember my dad coming home one day and telling us of a lost driveshaft scare he's had... IIRC he said it came from the opposite side of the freeway bouncing/flailing end over end through traffic, hopped the center divider for another bounce or two before impaling itself javelin style into an ice-plant covered embankment.

I've heard, (but don't know to be fact) that US Federal Motor Vehicle Safety Standards now require vehicles contain and prevent driveshaft separation in the event of joint failure.

Erik

Reply to
Erik

"Ignoramus27351" wrote in message news:8pidnXXLecRd88jPnZ2dnUVZ snipped-for-privacy@giganews.com...

Mine didn't either. IIRC wiggling a jacked-up tire showed the loose u-joint better than trying to turn the driveshaft when the wheels were on the ground and the parking brake applied. Unbolting it was even better but I had to go out to buy a 12mm 12 point flex socket to get the front one off, and more importantly to torque it back on. jsw

Reply to
Jim Wilkins

When I was living in Wichita around 1981 a woman was killed when a IIRC plastic drain fitting fell off another vehicle and smashed through her windscreen. I myself have received minor facial cuts when a rock was jettisoned from a tipper truck, possibly having been stuck between the twin rear wheels, hit the back edge of the bonnet (US hood) and smashed the windscreen in front of me puncturing the laminated interlayer, fortunately I saw it coming in time the shut my eyes. Luckily no one else was in the car as they would have been showered in glass shards. I was surprised just how much glass was in the car from front to back, it got everywhere.

Reply to
David Billington

Oh OH! That is NOT a good symptom. It may be a combination of gear and speed, but if it really is only in one gear, it could mean transmission trouble.

Jon

Reply to
Jon Elson

Jon Elson fired this volley in news:HoidnZAr27fPMcjPnZ2dnUVZ snipped-for-privacy@giganews.com:

Really? (not making fun of you, Jon. It's just that the idea was ridiculed not 24 hours ago.)

Lloyd

Reply to
Lloyd E. Sponenburgh

Just making sure, I think that I did not ridicule anything. I hope. Anyway, this pick-up towed a lot of stuff. So, while I would hate the idea of transmission trouble, it could mean that. I will have one mbile mechanic I trust stop by tomorrow, I will see what he says.

i
Reply to
Ignoramus27351

Ignoramus27351 fired this volley in news:tMWdnRWjV9DbV8jPnZ2dnUVZ snipped-for-privacy@giganews.com:

No, you didn't, Ig.

High-rate stumbling in one gear is a pretty sure sign of a clutch failing (rapidly, at this point). It's not _always_ expensive, but almost always involves a 'pro'.

Lloyd

Reply to
Lloyd E. Sponenburgh

Your clutch comment reminded me of a mate in high school in Wichita around 1982 and he had an odd vibration on his pick-up and when the school shop looked at it they found the flywheel had a crack around the central hub about 3/4 of the way round by the time they pulled it.

Reply to
David Billington

If I ever go this far, I'm changing them - no matter what. I still believe in the clunk clunk sound forward to reverse for u-joints going out. Don't know if his truck has a carrier bearing, though I doubt it would contribute to the vibration.

I lean strongly to tires or wheels. Have a Freightliner that always had a very noticeable vibration at 46-47 MPH, gone by 48. It was much more obvious on acceleration, not so much on deceleration. Had to change those tires 2 months ago, made a good deal on Michelins - no more vibration. Go figure! YMMV.

Reply to
DanG

A highschool classmate had a big-block '67 Chevy that he used to drive pretty hard - Tearing down the street behind the school and speedshifting, he took out the front U-joint and poked the driveshaft right through the diff into the gas-tank - lifting the rear bumper a few feet in the process and tearing a furrow in the asphault.

Had the rear U-Joint let go on the AeroScare on the way from Kitchener to Winnipeg, via Michigan. I had the u-joint replaced by a shop while I was out of the country in Burkina Faso for a month, knowing I had the winnipeg trip coming up as soon as I got home, taking my daughter to University. The mechanic who installed it didn't get the retainer clip in right and it threw a cup just east of Flint, friday of the Labour Day weekend. No tools in the truck - no shop able to do the job - changed it laying on my back under the truck with a combination of borrowed tools and a vice and hammer I bought at the parts store where I bought the U-Joint.

Reply to
clare

If it seams like it might be transmission related, get a can of BG ATC. If it is a sticky or floating valve in the trans it could quite possibly solve the problem and it definitely won't hurt. It won't fix a mechanical problem - but can solve accumulator and valve related issues, as well as some friction material issues. If it makes a difference you KNOW it is transmission related and you can decide how much you are willing to do to the tranny. If it doesn't help, it's only about 8 bucks.

Reply to
clare

My buddy with the '67 Goat went through driveshafts, trannies, diff nuts, and axles like -popcorn-, but he never went pole vaulting. I used to kid him about all the money he threw away by being so aggressive behind the wheel.

When I stood on my Javelin, the whole rear end dropped 7 inches as it wrapped the springs around the axle, but it then shot like an arrow. The close ratio Borg tranny was hard to keep up with behind the slightly built 390. (circa 400hp and 450ft#) I'm really surprised I never lost a u-joint.

I hope you asked for and got a full refund from the jerk who did that to you. "Refund or lawsuit, what'll it be, sir?"

Reply to
Larry Jaques

The "jerk" was my kid brother - and yes, I got a full refund!!!

Reply to
clare

Good, but here's some advice:

Never [I repeat: -NEVER-] hire family or friends to do work for you. You'll lose your ass or lose your friend, and neither is worth it. I hope he understands the possible ramifications of screwing up something so important. Someone could have been killed, including you.

P.S: What's "burkina faso"? Is it contagious? ;)

Reply to
Larry Jaques

Like myself, my brother is a professional mechanic. He just sold his shop last year. He knows. It was his mechanic that actually installed it I think.

Burkina Faso is a landlocked country in West Africa, formerly known as "Upper Volta", and Africa DOES seem to be contageous - either that or inherited, as my daughter (yes, the one we were taking to Wininpeg) has worked in and with Africa a lot since graduation.

Reply to
clare

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