Vibrations at 60-70

[dcfd470]

I have a vibration on my 1999 4 door tahoe at 60-70 MPH. Also it comes and goes depending on going up hills and/or when there is a load or trailer. It also seems to come out of nowhere at times. I have had tires and wheels balanced, Drive shaft balanced, New u joints, All new front end stuff including wheel bearings, Changed fluids in rear, transfer case and front differential everything looked good no metal shavings in any of them. I have also changed wheels and tires to another set with no improvement. I have shifted to neutral several times when it starts to vibrate and it is still there. I thought maybe a pinion gear or bearings or something else in the rear. I changed it out the rear and I still have the vibrations from time to time. Could it be something with the 4 wd components? I may change out the transfer case next. Right now it will not go into 4wd low. Any suggestions? Thanks.

 

[dcfd470]

I have a vibration on my 1999 4 door tahoe at 60-70 MPH. Also it comes and goes depending on going up hills and/or when there is a load or trailer. It also seems to come out of nowhere at times. I have had tires and wheels balanced, Drive shaft balanced, New u joints, All new front end stuff including wheel bearings, Changed fluids in rear, transfer case and front differential everything looked good no metal shavings in any of them. I have also changed wheels and tires to another set with no improvement. I have shifted to neutral several times when it starts to vibrate and it is still there. I thought maybe a pinion gear or bearings or something else in the rear. I changed it out the rear and I still have the vibrations from time to time. Could it be something with the 4 wd components? I may change out the transfer case next. Right now it will not go into 4wd low. Any suggestions? Thanks.

I am also hearing possible Torque converter? But will it still do this even in Neutral if it is?

 

[exp500]

Rotate your tires front to back and see if vibration follows. Determine first whether it is from front or rear. Any Strange wear on tires that you can feel with your hand running along tread??

 

[dcfd470]

Rotate your tires front to back and see if vibration follows. Determine first whether it is from front or rear. Any Strange wear on tires that you can feel with your hand running along tread??

I have done all of that already no change even with different wheels and tires.

 

[B-train]

Does the vibration change with engine RPM, or just speed. Knowing that will determine whether engine related, and then go after driveline. As asked earlier, can you pinpoint the perceived location of the vibration? Is it in the steering wheel, under your butt in the seat, etc?

 

[dcfd470]

Does the vibration change with engine RPM, or just speed. Knowing that will determine whether engine related, and then go after driveline. As asked earlier, can you pinpoint the perceived location of the vibration? Is it in the steering wheel, under your butt in the seat, etc?

It is underneath and it seems like it happens when RMPs go down. Uphill with a trailer or at 60ish with a trailer. It does happen very little without a trailer also. I did have a misfire in the summer and that was fixed end up being a distributor. I have placed it into neutral at 60ish mph when it starts vibrating and it dose not change anything so I am eliminating the engine being the problem. Don't know about the torque converter if it would still vibrate in neutral or not. The only thing that have have not replaced is the transmission or the transfer case. It will not go into 4wd either I don't know if that could b the problem?
.

 

[B-train]

Maybe on the t-case, but I would think it would be more constant if that were the case. Although, if there is slop inside that changes under load, possibly.

How many miles on the vehicle and transmission? What was the trans service history? If sounds like torque converter shudder to me. I know in the 99 and newer 4L60E transmissions they had valve body issues that would allow too much slippage for the TCC. The fix was a shift kit to keep the PWM solenoid from engaging slowly and increase the line pressure. Or just replace the valve body.

Without driving it, I'm only speculating. Do you have a scanner where you can see TCC slippage?

 

[exp500]

Does it happen on the same road in the same place? Maybe you just didn't notice.