Vibration when accellerating......HELP!
July 22nd, 2010, 7:03 PM
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Vibration when accellerating......HELP!
Guys~
I have a 2001 chevy Silverado with a 4.8L, Automatic Allison Transmission, Posi Rear end.
Need a little help with an issue that I am having. As of late, I have noticed that when I accellerate, I get a slight vibration on the floorboard. THis vibration seems to get worse if I accelerate harder. Almost feels like a U-Joint, but whle on the lift, I checked them all for play and could not find any. I have a split drive shaft...and just recently had the hangar bearing replaced, as it was clearly worn out.
One other thing I have noticed is that the truck does not downshift as easily as it used to. When driving up a settp incline....the truck with bog down and will eventually down shift, and then exhibit the vibration described above.
Transmission fluid looks bright red, clear and not burned. Level is within tolerance. Had the transmission backflushed and B&G synthetic fluid added over 20K miles ago. I have NEVER had the pan off, NOR have I replaced the filter. You know the story, the guys at Chevy told me not to replace it, but backflush it with the B&G system. Should I replace that filter?
Next thing to do I guess is to have the pressure checked. I have a Code reader and checked the PCM for codes relating to the tranny but there were none....
Oh yeah...when in third gear....the truck almost appears to shift twice into third...it is give a slight hesitation, then shift into 3rd.
Alot of info I know but wanted to lay it all out there....What do you think????? Perhaps a failing Transmission Pressure Control Solenoid? Wouldn't I get a code for this? Or is my Tranny about ready to pack it in....
Thanks ~ Brian
I have a 2001 chevy Silverado with a 4.8L, Automatic Allison Transmission, Posi Rear end.
Need a little help with an issue that I am having. As of late, I have noticed that when I accellerate, I get a slight vibration on the floorboard. THis vibration seems to get worse if I accelerate harder. Almost feels like a U-Joint, but whle on the lift, I checked them all for play and could not find any. I have a split drive shaft...and just recently had the hangar bearing replaced, as it was clearly worn out.
One other thing I have noticed is that the truck does not downshift as easily as it used to. When driving up a settp incline....the truck with bog down and will eventually down shift, and then exhibit the vibration described above.
Transmission fluid looks bright red, clear and not burned. Level is within tolerance. Had the transmission backflushed and B&G synthetic fluid added over 20K miles ago. I have NEVER had the pan off, NOR have I replaced the filter. You know the story, the guys at Chevy told me not to replace it, but backflush it with the B&G system. Should I replace that filter?
Next thing to do I guess is to have the pressure checked. I have a Code reader and checked the PCM for codes relating to the tranny but there were none....
Oh yeah...when in third gear....the truck almost appears to shift twice into third...it is give a slight hesitation, then shift into 3rd.
Alot of info I know but wanted to lay it all out there....What do you think????? Perhaps a failing Transmission Pressure Control Solenoid? Wouldn't I get a code for this? Or is my Tranny about ready to pack it in....
Thanks ~ Brian
July 22nd, 2010, 8:05 PM
#4
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The only way to truly check a u joint is to remove the drive shaft and check to see if the u-joints move freely. Most likely you have one binding. You are describing a u-joint or axle problem to a tee. There is no reason to remove the trans pan. Changing the filter is a thing of the past, filters are not what they used to be. The BG trans flush machine will clean it.
July 27th, 2010, 4:01 PM
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New Symptoms
Guys
Have not got under the truck to check the U-Joints, but I have a new symptom to add to the mix. Backed out of the driveway tonight ANC when I put the truck in drive, the transmission seemed to slip. This has happened twice before. Checked for codes...none. Also, when the truck is placed in 3rd vice overdrive, the transmission seems to shift fine from first to second, but from second to third the tranny almost seems to shift twice. I'm hoping that the transmission is not just about ready to go. What do you think? Could this be the clutch pack in the rear end going as well? Your thoughts.
- Brian
Have not got under the truck to check the U-Joints, but I have a new symptom to add to the mix. Backed out of the driveway tonight ANC when I put the truck in drive, the transmission seemed to slip. This has happened twice before. Checked for codes...none. Also, when the truck is placed in 3rd vice overdrive, the transmission seems to shift fine from first to second, but from second to third the tranny almost seems to shift twice. I'm hoping that the transmission is not just about ready to go. What do you think? Could this be the clutch pack in the rear end going as well? Your thoughts.
- Brian
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greatwhite99
Tahoe & Suburban
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August 27th, 2011 4:00 PM
1500, 2001, accelerating, accellerating, allison, bpeter3429, chevy, end, overdrive, rear, symtoms, transmission, truck, vibrates, vibration
