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1999 GMC Sierra 5.3 Extended Cab RWD. A long time ago I talked with Eric about this. Okay, I’ve been dealing with this problem ever since I got the truck in 2010 mostly because money is tight and I don’t want to throw parts at it. The main problem is on some freeway surfaces, I get an intense vibration/shaking between 60 and 70 miles per hour. It will usually stop after 70, but it can still be felt slightly. The shaking can be felt through the entire vehicle and the steering wheel. It feels like someone is grabbing you and shaking you 4 or 5 times per second. I haven’t gone through everything in the service manual, but I will tell you what’s been done.
I’m on my 2nd set of tires. Original tires did this – had them rebalanced several times. I bought a new set of BFGs – basically the same thing – balanced several times. I got the tire shop to replace the BFGs with Michelins (The most expensive tire for this truck) – same thing. Balancing doesn’t effect it very much.
I’ve taken the truck up to 75 MPH and then put the truck into neutral. Coasting down through the problem range – problem is still present.
The shocks are Bilstein heavy duty – perhaps a little too stiff, but all the shocks did was make the shaking/vibrating more noticeable. Ride can be a little rough though.
I’ve had two alignments within the past year. A GM mechanic I spoke with blames the alignment – this doesn’t make sense to me.
I’ve retorqued the ball joint nuts, lower control arm bolts, power steering rack bolts, tie rod ends, sway bar end links.
Ball joints do not appear to have any play when a giant pry bar is placed underneath the supported tire.
Truck has a two piece drive shaft. There doesn’t seem to be any play in the center bearing or the u-joints.
Some things I’ve also noticed: if I have an extra four or five hundred pounds in the truck (cab or bed) the vibration is greatly reduced or is eliminated. I do not think I am suffering from the infamous “frame beaming.” This shaking is much too intense.
I haven’t had a change to get under the truck to measure the suspension per the service manual but I found this interesting.Measuring from the top of the tires diagonally to the fender I get different measurements (my 1990 regular cab is basically the same side to side).
Front left: 5 and 1/16 inches
Front right: 4 and 3/4 inches
Rear left: 6 and 1/4
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As for tires when I put them on the balancer it’s easy to see if there is an abnormality there, sometimes a tire will balance out fine but you can clearly see a belt separation problem or something like that as the tire will ‘wobble’ as it spins. It’s not easy to see just by looking at the tire. It’s also possible that the driveshaft itself is out of balance, you might consider haivng it checked where you had the U joints done if you haven’t already.
Update:
It’s definitely NOT the tires. I scored a set of rims/tires from a 2011 Silverado with about 1000 miles on them for a good deal (The guy lifted it a little and put on big tires). Rims and tires are perfect and were rebalanced after he took out his TPMS. Same thing happens as always. Although the sidewalls seem stiffer and the truck seems a little more responsive in turns and going over speed bumps or dips. I think that’s because theses are 17s not 16s and the tires are slightly narrower. The rims look really nice though, lol. Gotta look at the bright side.
I was thinking maybe the bed is bouncing with no weight, but a few days ago I had about 250lbs back there and it didn’t do a thing.
I’m going to have to do some major brain storming to figure out what to look at next.
If it didn’t do it while it was loaded it could also indicate a driveline issue, when the vehicle is loaded it puts more stress on those components thus taking up any ‘slack’ in any loose parts in the driveline. I’d love to see a pic with the new wheels if you get the time.
Are you still dealing with the issues previously mentioned in this post? Your vibration sound like (to me) the driveshaft angle is off. I have seen this same thing many many times with two piece driveshafts. Loosen both of your center bearing bolts and add a 1/8″ alignment shimm between the bearing plate and the frame, the retorque (you can use regular washers if you don’t have alignment shims). You should notice a difference when you drive it, if it is better, but still there, add more shim. If it worse than the driveshaft needs to go up which may indicate a sagging frame. All I have delt with required shimming the driveshaft down. And as far as the clunk goes, the front yoke into the trans is a very common issue. GM sells a synthetic lube in a 1 qt can to lube the splines. I’m not sure if there are smaller containers. If you go to a Chevy dealership, just tell the parts guy you arte looking for driveshaft spline lube and he will know what you are talking about. If you want I can get you a GM part number on this (I have a can at work).
This drive shaft angle has been mentioned to the original poster before by myself a few posts back C8-) but im not sure if he has looked into that yet.
Hopefully we will get an update soon!
Eric – I will snap some pictures for you. It’s nothing fancy though I put stuff in the back occasionally and it gets me to work.
Baxman – you are pretty much on point to what I’ve been looking into lately. Recently I spaced out the center bearing with various combinations of washers, and it seemed to make the vibration worse. So naturally I removed the washers afterwards. Pinion angle is definitely a concern – I’m not sure if it is adjustable in these trucks or not. I want to pick up a cheap angle finder to get an idea of what the angle is.
Also, I just picked up another driveshaft from an 04 Silverado with the same specs as mine for 50 bucks. I thought it would be good just to rule out the driveshaft. I haven’t installed it yet, there is a little surface rust on the yoke that needs to get cleaned up first. The guy I picked up from was pretty cool and had a heavily modified truck. He told me he had the same problem, so he went to a one piece driveshaft, no luck. Turned out his rear end was the problem, eventually the pumpkin died and spit out pieces through the diff cover! New rear end fixed all his vibrations.
After spacing out the center bearing it seems like my vibration is getting worse. I can feel a slight vibration through the steering wheel/body at pretty much any speed, but of course 60-70 is bad on some highways. Sometimes even a little below 60 or above 70 will give me problems. But this thing is getting worse. I think there has always been a slight vibration through the steering wheel, but it very noticeable now.
About the frame – I have thought about taking it to a good frame shop to have them make sure everything is square and straight.
So I think it’s definitely a driveline issue. I hope it’s not the rear end or transmission, but I think that may be the case. I appreciate the help and comments guys. Oh, and Baxman, the part number would be great if you can remember it.
I will get you a part number tomm (Friday). And yes the rear axle is adjustable through wedge style angle shims between the axle and leaf springs. I have not done this myself so I have no advice on this possible repair. I chope this is all it will take to remedy your concern
Here is the info on the GM driveshaft spline lube. Part Number: 12345879. It is in a 16 oz can. It’s called Special Lubricant and is high temperature, ptfe filled and non-melting (all printed on the label). I would like to think that there could be a better name for it, oh well. It does work well.
Well, the 50 dollar driveshaft was a bust. Does the same thing and my original one that’s been rebalanced/new u-joints/center bearing. It has to be the rear end/pinion angle or the transmission. I can get a good 1/4 inch of play from the pinion when I try to rotate it by hand with the transmission in neutral.
No, I would like a dial indicator though. It’s a great tool to have, especially in these circumstances.
I’m thinking it’s in the differential then I’ve hardly ever seen a transmission cause a problem like yours but I suppose it is possible, I’d be doing a gear backlash check to see if it’s in spec, the procedure should be listed in a service manual somewhere along with the spec. I don’t have a video on this but you will need a dial indicator gauge with a magnet that mounts to the outside of the case. It probably won’t be a bad idea to check the tooth contact pattern with paint to see if the gears are meshing correctly. I’m concerned that when you open up the diff you may find some damage. Too bad those diffs don’t have a drain plug as you could just check the fluid for metal shavings. Keep us posted.
Eric, these diffs do have a drain and a fill plug. I changed the fluid and gasket a few thousand miles ago. It was pretty nasty looking and the magnet had plenty of stuff on it. There was one spider gear that had a damaged tooth, and the magnet caught the part that came off. I guess it wouldn’t hurt to check it out again and see if any additional damaged has occurred. Maybe it is just getting ready to grenade. It mad e a strange noise today when I was reversing – like snap or something. Who knows with that though, I could have run over something.
I can feel a constant vibration in the steering wheel no matter what now and it can get worse with engine load, so I was thinking about the torque converter in regards to that.
I jacked up the rear and watched the tires spin at idle, so about 10 mph. I didn’t see anything crazy with the driveshaft. The rear tire appears to be spinning true and straight. Okay I know with an open diff one tire should spin forward and the other backwards. However, what if just the driver side spins and passenger side hardly moves at all? Gears really are my thing at all…
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