i ve seen this posted a few times, but have not seen any fixes. i have the "bump" in the rear of the truck upon acceleration, and when coming to a complete stop. doesnt do it all the time depending on take off/ slow down, but its quite often. i've changed all ujoints front and back, replaced a bad rear output shaft transfer case bearing, greased output spline, still no progress. posibly in rear end? dont know.
rear end bump?
- Thread starter mygreen98
- Start date
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sasquatch094
Full Access Member
Do you have any aftermarket rear suspension components? check all the shocks and leaf springs bolts. sometimes they come a little lose and can create a small movement (play in the suspension) that can be felt inside the truck... check and tighten them all down.. try it out
96ProCompTahoe
Full Access Member
i got the same problem. should have thought of that before it got all covered with salt and crap yesterday...
jwpotts0413
Full Access Member
it's the slip yoke, inherent design flaw. unless you got something else wrong too...
u can remove the slip yoke and regrease every oil change (pain in the ass) or u can get a nickel plated slip yoke.
ETA: it's nothing to worry about every 4x4 tahoe i've ever driven does this. remember you ain't driving a sports car, it's a tahoe! if you ease onto the throttle and brakes, it probably won't be as noticeable.
u can remove the slip yoke and regrease every oil change (pain in the ass) or u can get a nickel plated slip yoke.
ETA: it's nothing to worry about every 4x4 tahoe i've ever driven does this. remember you ain't driving a sports car, it's a tahoe! if you ease onto the throttle and brakes, it probably won't be as noticeable.
jwpotts0413
Full Access Member
i'd keep checking, as stated earlier check tranny mounts and transfer case. could easily be the gimbal bearing in the rear end. could also be worn axle splines, the list is endless. drive it till it breaks, then fix it
jwpotts0413
Full Access Member
obviously check body mounts and suspension mounts as well. mine does the same thing and it drives me nuts. especially when you slow down for a red light and it turns green before you get there it goes "clunk" right when you hit the gas. everything on my truck is fine, short of opening the hog head on the rear differential. i've been told it's the slip yoke by GM. they said they released an updated nickel plated one that will fix my problem. based on their engineer's design of my transmission's valve body and seperator plate, i have a hard time trusting their technical advice. their engineering department is half-retarded to say the least...
agree jw, i do think its in the rear. i think im guna open it up and take a look this week. your description at red/green light is on the money. very annoying. if you feather the pedal you can avoid the bump most times. i'll post my findings.
jwpotts0413
Full Access Member
lemme know if you find anything, mine still does it(132k miles)...and has been doing it since i bought the truck(112k miles)
My Yukon is doing this too at 192k. It just started doing it this summer though.
What I have noticed though is that it does it more when my truck warms up or is driven for an hour in city traffic. From a cold start, it seems to do it less. Do you guy notice the same thing?
We are definately experiencing the issue though. It happens on a hard stop, one bump from the rear and one sometime two bumps as i accelerate from a stop. Sometimes more of a bump then others and sometimes it makes a little chrip noise.
SUPER ANNOYING.
What I have noticed though is that it does it more when my truck warms up or is driven for an hour in city traffic. From a cold start, it seems to do it less. Do you guy notice the same thing?
We are definately experiencing the issue though. It happens on a hard stop, one bump from the rear and one sometime two bumps as i accelerate from a stop. Sometimes more of a bump then others and sometimes it makes a little chrip noise.
SUPER ANNOYING.
diesel1114
New Member
hey guys omg yea i hate it its really annoying, i havent checked to see if it any rear suspension is loose i thought it was my rear shocks , just got teh truck 2 weeks ago , so i just changed it and i was like w t f still a noise man, i herd there is / was a tsb 4 this problem , i wanted to try to call my local dealer todfay to see if thy woud honor a tsb , im just the tsb # for it but yea if anytone has a soultion please do share and as far as the suspension checking for tightness man if it wasnt so cold here in nyc and teh truck was full of slat , which i cant keep the stuff off man i tell u id go under with the impact gun and hit all the bolts
I will bet that 90% of all the bumping is the slip yoke on the front of the rear drive shaft.
Every time you come to a stop or accelerate, the body of the truck will respond to the movement. It dives forward when stopping and rocks backward when accelerating.
The rear axle housing is attached to the body by leaf springs that are fixed in the front and hanging by shackles in the rear to allow the housing to rotate as the suspension goes up and down.
If you could have a video camera looking at the yoke from the side, you would see it moving in and out every time you hit a bump, or speed up or slow down. When coming to a hard stop, it moves the farthest. If it is sticking, it will stay in the compressed position as you come to a stop, holding the brake. Sometimes, as soon as you relax the brakes, it is enough torque released from the splines, that it will slip back to the relaxed position. Otherwise acceleration will force it to snap loose, as the axle housing, goes to the other extreme of it’s normal fluctuating range of movement.
This action is mostly eliminated by vehicles with coil spring suspension because of the different manner of mounting the axle housing.
Everyone has their own idea as to how much grease these yokes should have. From the factory, they depend on ATF from the trans/transfer case to keep them lubricated. After years and millions of cycles of sliding in and out, they can dry out or become worn. It kind of depends on the environment they have been in and even how rough the roads have been during their life. Lots of variables.
The average owner is not willing to go through the hassle of pulling the drive shaft out and cleaning and greasing the tail shaft. In extreme case where grease does not solve the problem, the new improved yoke may be a good idea,
but the tail shaft itself, should also to be considered as half the problem from the stand point of wear.
If any other suspension components have been moving enough to cause the thumping, there should be some evidence of that movement. Look closely before getting out the breaker bar to tighten bolts. Many of the bolts holding things together back there are likely to break off, before they will turn if they have the normal amount of corrosion.
My experience has been that the thump occurs as the brakes are released, after stopping. Sometimes you can eliminate the drive shaft spline from the issue if you slip the trans into neutral before stopping. That should release the torque from the spline while stopping.
Just my .02…………………
Every time you come to a stop or accelerate, the body of the truck will respond to the movement. It dives forward when stopping and rocks backward when accelerating.
The rear axle housing is attached to the body by leaf springs that are fixed in the front and hanging by shackles in the rear to allow the housing to rotate as the suspension goes up and down.
If you could have a video camera looking at the yoke from the side, you would see it moving in and out every time you hit a bump, or speed up or slow down. When coming to a hard stop, it moves the farthest. If it is sticking, it will stay in the compressed position as you come to a stop, holding the brake. Sometimes, as soon as you relax the brakes, it is enough torque released from the splines, that it will slip back to the relaxed position. Otherwise acceleration will force it to snap loose, as the axle housing, goes to the other extreme of it’s normal fluctuating range of movement.
This action is mostly eliminated by vehicles with coil spring suspension because of the different manner of mounting the axle housing.
Everyone has their own idea as to how much grease these yokes should have. From the factory, they depend on ATF from the trans/transfer case to keep them lubricated. After years and millions of cycles of sliding in and out, they can dry out or become worn. It kind of depends on the environment they have been in and even how rough the roads have been during their life. Lots of variables.
The average owner is not willing to go through the hassle of pulling the drive shaft out and cleaning and greasing the tail shaft. In extreme case where grease does not solve the problem, the new improved yoke may be a good idea,
but the tail shaft itself, should also to be considered as half the problem from the stand point of wear.
If any other suspension components have been moving enough to cause the thumping, there should be some evidence of that movement. Look closely before getting out the breaker bar to tighten bolts. Many of the bolts holding things together back there are likely to break off, before they will turn if they have the normal amount of corrosion.
My experience has been that the thump occurs as the brakes are released, after stopping. Sometimes you can eliminate the drive shaft spline from the issue if you slip the trans into neutral before stopping. That should release the torque from the spline while stopping.
Just my .02…………………
