2001 Z71 Vibration

centurion350 · July 16, 2011

Maybe try putting your t bars back to stock settings

i have an appointment at the alignment shop for tomorrow morning and will try this. I have another Z71 that is a 2003 with extended cab, it is set up the same way and does not vibrate.

will check it and report back. the short wheel base does make for a different natural frequency of vibration for the vehicle suspension.

centurion350 · July 16, 2011

I am thinking driveshaft also. They should be able to diagnose anything drive-train related on a hoist.

this truck is a four wheel drive and is also a short wheel step side with the fiberglass bed. a few years back Chevrolet had a recall on the driveshafts in the trucks replacing them with a large diameter aluninum shaft (waht was shiooed from GM was a normal diameter shaft of steel. the theory as per the GM Dealer was that the short steel shaft had a natural frequency issue but what i found out from another tech at the Truck GM plant (in Canada) was that a bunch of the shafts had went through the balance shop with the weights on on the shaft but installed on the wrong ends. the short large diameter aluminum shaft is no longer available so i tool the shaft out of the truck and had it rebalanced to 125 MPH at the local performance shop. no effect on the vibration after reinstallation.

ChevyTech77 · July 16, 2011

Lift the rear of the vehicle and rest the rear axle on jack stands, on a solid surface of course, so that the tires are off the ground. Run the vehicle up through the gears to the speed in which the vibration is normally present. Is the vibration still there?

earlier in the discussion i metioned that i have already did this twice. it is as smooth as a quiet lake on Jack stands. have did it on all four.

Sorry, I must have missed that.

I've never seen a vibration that was gone with the tires off the ground NOT caused by tires. There really is not other changes that you are making to the vehicle's dynamics by putting it on jackstands other than taking tires off the ground, as long the jackstands are placed so as the suspension still has the weight of the vehicle on it which keeps the driveline angles as they would be going down the road.

centurion350 · July 16, 2011

Lift the rear of the vehicle and rest the rear axle on jack stands, on a solid surface of course, so that the tires are off the ground. Run the vehicle up through the gears to the speed in which the vibration is normally present. Is the vibration still there?

earlier in the discussion i metioned that i have already did this twice. it is as smooth as a quiet lake on Jack stands. have did it on all four.

Sorry, I must have missed that.

I've never seen a vibration that was gone with the tires off the ground NOT caused by tires. There really is not other changes that you are making to the vehicle's dynamics by putting it on jackstands other than taking tires off the ground, as long the jackstands are placed so as the suspension still has the weight of the vehicle on it which keeps the driveline angles as they would be going down the road.

i will know in a little bit as i am off to the shop with it.

we will see. if it were not for having to drive on INterstate 95, where you have to reach the speed of light to live i would really not worry too much. i am basically a road speed limit driver, most of the time. so 55 would be pretty easy to live with.

did notice one thing yesterday......at 65 with my car trailer (not loaded) on the truck the vibration was much lower.

ChevyTech77 · July 16, 2011

did notice one thing yesterday......at 65 with my car trailer (not loaded) on the truck the vibration was much lower.

Sounds like just what I suspected, tire vibration making your frame beam. Swap to a completely different set of tires and wheels and then add 3-400 lbs of weight to the back of the pickup bed, against the tailgate, and try that.

pistonslap · July 16, 2011

Have you checked the rims for bends? and have you checked the axels to see if they are bent? I ran across this problem on a friends truck and turns out he had a bent axelshaft in the back.

have rotated the tires and rims on machine to check for true......almost perfect and this is the second set of rims on the truck.....both times it vibrated.

checked the rear axels at the time i replaced the bearings ...... good to go on a lathe.

changed bearings in the front and checked the shafts in front for true but hard to do as an assembly.

another technician said to take the drive shaft off the front drive and see if it still vibrates. the dealer said this is a no-no for an automatic truck.

this same technician said to take the rear drive shaft out and drive the truck with just the front. the dealer said this is a no-no also.

thanks

I have had my front drive shaft out for over a month with no problems. (2000 1500 4X4 SWB)

centurion350 · July 18, 2011

Have you checked the rims for bends? and have you checked the axels to see if they are bent? I ran across this problem on a friends truck and turns out he had a bent axelshaft in the back.

have rotated the tires and rims on machine to check for true......almost perfect and this is the second set of rims on the truck.....both times it vibrated.

checked the rear axels at the time i replaced the bearings ...... good to go on a lathe.

changed bearings in the front and checked the shafts in front for true but hard to do as an assembly.

another technician said to take the drive shaft off the front drive and see if it still vibrates. the dealer said this is a no-no for an automatic truck.

this same technician said to take the rear drive shaft out and drive the truck with just the front. the dealer said this is a no-no also.

thanks

I have had my front drive shaft out for over a month with no problems. (2000 1500 4X4 SWB)

well, i will try it if the T bar issue dont work. went to the shop but the alignment machine was down all day on Saturday. they are going to try it on Monday..

centurion350 · July 22, 2011

Have you checked the rims for bends? and have you checked the axels to see if they are bent? I ran across this problem on a friends truck and turns out he had a bent axelshaft in the back.

have rotated the tires and rims on machine to check for true......almost perfect and this is the second set of rims on the truck.....both times it vibrated.

checked the rear axels at the time i replaced the bearings ...... good to go on a lathe.

changed bearings in the front and checked the shafts in front for true but hard to do as an assembly.

another technician said to take the drive shaft off the front drive and see if it still vibrates. the dealer said this is a no-no for an automatic truck.

this same technician said to take the rear drive shaft out and drive the truck with just the front. the dealer said this is a no-no also.

thanks

I have had my front drive shaft out for over a month with no problems. (2000 1500 4X4 SWB)

well, i will try it if the T bar issue dont work. went to the shop but the alignment machine was down all day on Saturday. they are going to try it on Monday..

well

sorry i did not get back earlier but was out of state on business.

While i was gone the truck stayed at the shop, but a different shop, a dyno shop.

Here are the things they found:

1. the drive shaft although balanced is not right. the ends of the driveshaft are not welded into the drive shaft true position to each other so the shaft has mort than one axis. i would have thought that the balance company that i used to balance the shaft not long ago would have found this but found that this is not checked when a shaft is rebalanced only when it is manufactured..........so i have to get a new driveshaft......the next part of this story is i called GM about a replacment and the cost is $516 dollars. called the service department and found that the previous recall on the driveshaft on the shortwheel pickups was for this problem and the mis-balance issue ALSO. i was not told that the first time.

2. the next issue found was that my front driveshaft turns all the time, even when it is not in four wheel drive. The dealer in Fredericksburg tells me this is not suppose to be happening.........the transfer case has a failed clutch in it and needs to be rebuilt............junk yard one is $400, no price yet from Jasper. Told the tranfer case is out and not engaged that the vibration would reduce.......common for this type of vibration in the truck at 60+ MPH when the clutch does not disengage.

will report back when i get the transfer case repaired or replaced and the driveshaft replaced..........very hopefull.

the weird part of this is i have had this truck in several (probably 30) shops over the last 7 years and none have ever found these issues.

we will see.

Mckenzie · July 22, 2011

Have you checked the rims for bends? and have you checked the axels to see if they are bent? I ran across this problem on a friends truck and turns out he had a bent axelshaft in the back.

have rotated the tires and rims on machine to check for true......almost perfect and this is the second set of rims on the truck.....both times it vibrated.

checked the rear axels at the time i replaced the bearings ...... good to go on a lathe.

changed bearings in the front and checked the shafts in front for true but hard to do as an assembly.

another technician said to take the drive shaft off the front drive and see if it still vibrates. the dealer said this is a no-no for an automatic truck.

this same technician said to take the rear drive shaft out and drive the truck with just the front. the dealer said this is a no-no also.

thanks

I have had my front drive shaft out for over a month with no problems. (2000 1500 4X4 SWB)

well, i will try it if the T bar issue dont work. went to the shop but the alignment machine was down all day on Saturday. they are going to try it on Monday..

well

sorry i did not get back earlier but was out of state on business.

While i was gone the truck stayed at the shop, but a different shop, a dyno shop.

Here are the things they found:

1. the drive shaft although balanced is not right. the ends of the driveshaft are not welded into the drive shaft true position to each other so the shaft has mort than one axis. i would have thought that the balance company that i used to balance the shaft not long ago would have found this but found that this is not checked when a shaft is rebalanced only when it is manufactured..........so i have to get a new driveshaft......the next part of this story is i called GM about a replacment and the cost is $516 dollars. called the service department and found that the previous recall on the driveshaft on the shortwheel pickups was for this problem and the mis-balance issue ALSO. i was not told that the first time.

2. the next issue found was that my front driveshaft turns all the time, even when it is not in four wheel drive. The dealer in Fredericksburg tells me this is not suppose to be happening.........the transfer case has a failed clutch in it and needs to be rebuilt............junk yard one is $400, no price yet from Jasper. Told the tranfer case is out and not engaged that the vibration would reduce.......common for this type of vibration in the truck at 60+ MPH when the clutch does not disengage.

will report back when i get the transfer case repaired or replaced and the driveshaft replaced..........very hopefull.

the weird part of this is i have had this truck in several (probably 30) shops over the last 7 years and none have ever found these issues.

we will see.

The front drive shaft is always suppose to be turning, don't let them rip you off on that, that's completely normal. My 01 does it as well, i think it is what enables you to shift into 4HI on the fly.

http://www.gm-trucks.com/forums/index.php?...p;#entry1181023

centurion350 · August 22, 2011

Have you checked the rims for bends? and have you checked the axels to see if they are bent? I ran across this problem on a friends truck and turns out he had a bent axelshaft in the back.

have rotated the tires and rims on machine to check for true......almost perfect and this is the second set of rims on the truck.....both times it vibrated.

checked the rear axels at the time i replaced the bearings ...... good to go on a lathe.

changed bearings in the front and checked the shafts in front for true but hard to do as an assembly.

another technician said to take the drive shaft off the front drive and see if it still vibrates. the dealer said this is a no-no for an automatic truck.

this same technician said to take the rear drive shaft out and drive the truck with just the front. the dealer said this is a no-no also.

thanks

I have had my front drive shaft out for over a month with no problems. (2000 1500 4X4 SWB)

well, i will try it if the T bar issue dont work. went to the shop but the alignment machine was down all day on Saturday. they are going to try it on Monday..

well

sorry i did not get back earlier but was out of state on business.

While i was gone the truck stayed at the shop, but a different shop, a dyno shop.

Here are the things they found:

1. the drive shaft although balanced is not right. the ends of the driveshaft are not welded into the drive shaft true position to each other so the shaft has mort than one axis. i would have thought that the balance company that i used to balance the shaft not long ago would have found this but found that this is not checked when a shaft is rebalanced only when it is manufactured..........so i have to get a new driveshaft......the next part of this story is i called GM about a replacment and the cost is $516 dollars. called the service department and found that the previous recall on the driveshaft on the shortwheel pickups was for this problem and the mis-balance issue ALSO. i was not told that the first time.

2. the next issue found was that my front driveshaft turns all the time, even when it is not in four wheel drive. The dealer in Fredericksburg tells me this is not suppose to be happening.........the transfer case has a failed clutch in it and needs to be rebuilt............junk yard one is $400, no price yet from Jasper. Told the tranfer case is out and not engaged that the vibration would reduce.......common for this type of vibration in the truck at 60+ MPH when the clutch does not disengage.

will report back when i get the transfer case repaired or replaced and the driveshaft replaced..........very hopefull.

the weird part of this is i have had this truck in several (probably 30) shops over the last 7 years and none have ever found these issues.

we will see.

The front drive shaft is always suppose to be turning, don't let them rip you off on that, that's completely normal. My 01 does it as well, i think it is what enables you to shift into 4HI on the fly.

http://www.gm-trucks.com/forums/index.php?...p;#entry1181023

well sorry i have been out for a while and the truck has been in the shop.

so here goes:

Put in a new driveshaft, 4 in aluminum and it is real nice and true running. moved the vibration to 62 mph but still bad.

took the wheels of the 2003 and put them on the 2001....no difference but did find i had a bad right rear rotor on the 2001. replaced both rotors, both calipers, both brake hoses and put on new shoes allthe way around. No impact on the vibration.

man this is getting old.

mxeightyeight · February 16, 2012

Not to dig up an older thread but this sounds like "beam-shake" all day long. There was a TSB on this. I think the fix was to replace body mounts to help dampen the vibration. For whatever reason, it seems EXT. and REG cab trucks have it. Maybe someone can help me out with that. If I remember it said the vibration was between 45-55 mph. Hope this helps.