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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: 1979C20 on February 01, 2012, 12:50:42 am
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I developed an issue today. I drove my truck to work with no issues. When I left, i noticed a strange shaking that ive never felt before. Its only when im slowing down, it doesnt matter if.my clutch is in or out, brakes on or off, coasting to a slow stop or stopping quick, between 35 and 25 mph only, the whole cab of my truck shakes pretty dang bad. I crawled underneath it when I got home and I noticed my tranny mount bolts are missing and that my tranny was slid over 2 or 3 inches to the left. So im thinking that either my transmission is bouncing around a lot, or if because it was shifted over, if maybe my u-joint is shot. Is there a way to check if the u-joint is the problem other than replacing it? Does my issue sound like a u-joint? Thanks in advanced, and yes, im going to get my tranny mount all buttoned up.
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The way to check your u-joints. Hold one side still, try to move the other side, any movement, they are bad.
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Sounds like a loose wheel, wheel bearing, or a soft tire to me. Bad universals will usually vibrate instead of shake.
Put some bolts in the transmission mount and check it to make sure it is not bad then you can just check the universals for play with a bar or large screwdriver.
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Bad news about the tranny mount. That should be relatively straight forward to fix.
I've had small bulges (caused from a broken cord I think) in tires that can cause the type of vibration you are speaking of.
Check all 4 closely.
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Thirsty and firefighter are right. I always check tires first. ( tire separation, or throwing a weight ) will cause shakes. Also I have had two (heavier vehicles ) with warped rotors cause shakes at certain speeds, regardless if I was speeding up or slowing down, and always at a given range of speed.
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yes check tires for missing weights. check for clean spots on the wheels where the weights used to be, inside and outside. and busted wires can cause shaking but i think thats at all speeds
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The shaking started at 35 and stops at 25 only while im slowing.down. It doesnt shake while I accelerat or coast.during those speeds. The shaking starts at the cab, pretty much right at the bed gap. The bed does not shake, but my cab and my hood shake like crazy. Its almost like my ujoint is bad causing a vibration, and since my tranny mount is shot and my tranny slid.around, its resting against the trans tunnel and the ujoint vibration is going through the tranny and shaking the whole truck. Ive noticed more and more vibration in the shifter over the last month or so. The tires were the first thing I checked. All have good pressure and none are misshapen or worn weird.
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When your trans shifted 2-3" it altered your driveline angles. Fix your trans mount and your problem may go away. But, do it sooner than later so your your problem doesn't escalate to include a broken bellhousing and/or broken fan shroud. While you're at it check your motor mounts.
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Motor mounts are good, and the bolts from the bellhousing to the engine are nice and tight. I made sure of that when I noticed the tranny was shifted. Im going to get bolts into the tranny mount today and see if that fixes it. While im down there im going to check my ujoint and replace it if necessary. Ill let you know how it all goes. Thanks for the help guys.
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Never have I had a problem with drive lines causing vibrations. That's kind of like saying lifted truck will vibrate. I've had bad mounts and the only way I knew was a clunk while shifting. The drive shaft weight could of fell off also. But let me get this straight its been vibrating for the past month and you just now are trying to fix it. The bolts probably fell out due to the vibration
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i would bolt the trany cross member back in befor u drive it much more!
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No, it was just a slight vibration in the shifter. But this is shaking the whole truck. I had to pay rent today, so I wont have any money till tomorrow, so I buy some tranny bolts anf get that tightened up, and if its still vibrating, my u joint is still under warranty so Ill swap that out. If both of those dont solve it, ill have some investigating to do.
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Never have I had a problem with drive lines causing vibrations. That's kind of like saying lifted truck will vibrate. I've had bad mounts and the only way I knew was a clunk while shifting. The drive shaft weight could of fell off also. But let me get this straight its been vibrating for the past month and you just now are trying to fix it. The bolts probably fell out due to the vibration
I have had drive lines cause shaking, but only on extreme lifted trucks/jeeps where the drive lines were at extreme angles and not balanced.
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Never have I had a problem with drive lines causing vibrations. That's kind of like saying lifted truck will vibrate. I've had bad mounts and the only way I knew was a clunk while shifting. The drive shaft weight could of fell off also. But let me get this straight its been vibrating for the past month and you just now are trying to fix it. The bolts probably fell out due to the vibration
I have had drive lines cause shaking, but only on extreme lifted trucks/jeeps where the drive lines were at extreme angles and not balanced.
thats what i mean lol. but 79 you can buy any bolt from the hardware store for under a dollar. i would almost say around 30 cents
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My u joint is shot, gonna swap it out today. And my tranny mount is screwed, the bolts are through the crossmember, but the tranny is still shifted, so I have to.get a new one. Thanks for the.help guys.
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Okay then, when I was dropping my drive shaft, I found a 3rd part to my issue. My center support bearing(carrier bearing) was messed up. The rubber bushing seperated from the bearing. So my best bet is my tranny mount started this all, the ujoint went out because of the extreme angle, and the center support bearing bushing ripped because of the angle the driveline was going through it. So, my "friends" down at checker helped.me oit. We got the carrier bearing off and a new one on, replaced the ujoint, and I picked up a tranny mount. The best part is, it was all free!! I had life time warranties on all of it since I had already replaced them all before. The bad news is, when I tried to get my tranny mount out, the bolt just kept spinning inside.of the rubber of the mount. So I got a hack saw and started to cut the bolt, then the blade broke. Well, I was replacing everthing in the checker parking lot because I haf no way to pull the parts off,l and brong them in because my truck is my only transportation. So I had to leave the tranny mount for tonight. I have to pick up my girlfriend from work and checker was closing. Ill probably swap the new one in tonight some time.
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Glad u got it fugured out! exspecially for free!! lol!
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My u joint is shot, gonna swap it out today. And my tranny mount is screwed
Well that will certainly do it. I hope after fixing those it solves the problem. Keep us informed.
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Well, im stumped. Brand new u-joint. Brand new carrier bearing. Brand new transmission mount. Everything is in line and tight. Motor mounts are good. But, my truck is still shaking between 35 and 25. Its not quite as bad, but its atill very promineny. Its driving me nuts. I can fell a strong vibration in the steering wheel, and the cab is shaking. Any more ideas?
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Are your u-joints in time?
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Yes. My 2 piece drive line has a flat spine. Theres only one way it goes on. And all of the drive shaft weights are still on.
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If you set the vehicle up on secure jacks and removed the wheels (reverse the lug nuts to hold the drums on), do you suppose you would still have the vibration?
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I was thinking about doing this. Putting the rear axle on jack stands and then accelerating to just above 35, then slowing down to see if it still shakes that would narrow down the problem.area to the front of the truck if it doesnt shake. I just dont know how safe it is to have my truck on jack stands at that speed.
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Put several jack stands around the back. I have done this but 1 set I used had chains on it to strap to frame/axle. I was going to suggest front rotors or tires, but this way you can eliminate the rear end.
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Sounds like what people call the death wobble in four wheels drives the way you are describing it.
Don't you have newer wheels and larger tires on your truck? I would pull the wheels and check the lug holes to make sure that they aren't worn. Check the tires again for a broken belt. Go over all steering and suspension components closely.
I bought a K20 once that had the death wobble. On the test drive the guys tells me to power thru it and it will come out of it. I couldn't do it the first time...it was that bad, I had to pull over. Then I got it past the death wobble and it drove fine. I ended up buying it and replacing the stabilizer shock and a tie rod end. Never had a problem again. It had 33"s on it and the tires would do their own thing left to right until they really got rolling fast.
Maybe you have the same type of thing starting with yours even though it is 2wd.
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Death wobble is not limited to straight axle trucks.
A long time ago, a company I worked for had a worn out 85 2 wd dually flatbed truck that had death wobble issues. Everything was stock, just worn out.
Recently I saw a 90's F250 4x4 (Twin traction beam front end) begin the death wobble on the road... Interesting to see from the outside...
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Recently I saw a 90's F250 4x4 (Twin traction beam front end) begin the death wobble on the road... Interesting to see from the outside...
Isn't it? Really excessive caster can cause a shimmy too.... But, worn parts are probably the biggest offenders and oversize tires with aggressive open tread exaggerate the issue.
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I was told that ball jpints may be the culprit. Im going to check it all out tonight. Thanks guys.
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Okay, well I have gotten 6 suggestion that its ball joints. I didnt get a chance to check them yet, but im prepared to have to replace them. I have a set of coil sprin boosters that I want to install if I do have to replace them im going to do the uppers and lowers, replace my swaybar bushings, and going to install the upper ball joint UNDER the control arms so I have a little more suspension travel between the upper control arms and the crossmember. Im thinking about replacing my tie rod bushings as well. Just to freshen up the whole front end.