Driveline Vibration?

[8.1HD/ALLISON]

Just bought a 2004 2500HD CCLB with 8.1L and Allison. Truck had a vibration 40-45 mph area. I got to checking some things and found the rear u joint smoked. Replaced it and also replaced the carrier bearing while i was there. Heard they are prone to trouble and the rubber bushing wasn't looking the best. After reassembly I slid the carrier bearing all the way to the rear, now my vibration is around 45-50 mph. Thinking I need to dive in and check my propshaft angles. Just wondering if this is common with a crew cab long bed? Anyone else had this problem? Thanks for any help, Matt

[markw8]

Take the shaft out and make sure that all joints work smooth and free, don't just check for looseness. Especially if it has a C/V joint. Unless it's been lifted the angles shouldn't change.

 

Mark

[8.1HD/ALLISON]

Take the shaft out and make sure that all joints work smooth and free, don't just check for looseness. Especially if it has a C/V joint. Unless it's been lifted the angles shouldn't change.

 

Mark

 

 

Already had the propshaft out. Replaced failed rear u joint, also carrier bearing. Rear doesn't have c/v joints. No lift. Have been told driveline angles on the long trucks is usually off. Measured my angles last night, they are out of specs. Took the truck to the shop today and shimmed the tranny mount. took 3/4". Got the transfer case yoke to 4.5 degrees, the front propshaft at 5 degrees. Test drove it, seems better, but rear propshaft angle is at 3.5 degree. needs to be a little over 5 to keep the fall of the driveline. Checked some numbers and a 2 in rear spacer should get me 2.25 degrees. Just ordered a 2inch add a leaf from tuff country. According to my numbers that should put my rear propshaft angle at 5.75 degrees. Hope that will take care of it. Guess i will find out next week when my parts come in.

[8.1HD/ALLISON]

Got the add -a-a leaf in tonight. Got rear angle up to 5 degrees. Was hoping for a little more, but the truck sits better now. Has about 1 1/2 inch rake. Seems to drive a little better. Also noticed the shocks are bad while had apart. Checked online and ordered set of Rancho RS5000 shocks at advanceautoparts.com 20% off and free shipping. Score one for me!

[ezstriper]

Got the add -a-a leaf in tonight. Got rear angle up to 5 degrees. Was hoping for a little more, but the truck sits better now. Has about 1 1/2 inch rake. Seems to drive a little better. Also noticed the shocks are bad while had apart. Checked online and ordered set of Rancho RS5000 shocks at advanceautoparts.com 20% off and free shipping. Score one for me!

 

well I have a 05 crew SB with a duramax and been fighting a shimmy/vibration from the rear for years, 3 sets of tires, balances, rotations etc...ck U-joints etc...still there feels like the rear is bouncing horrible @ 40-50, when not loaded, tried lowered shackles, no good back to stock, tried air bags diff pressures... still there...so ???

[8.1HD/ALLISON]

I would take it to the local dealer and have them check the driveline angle. Compare to gm specs. Also can test drive with the eva2(electronic vibration analyzer) and see what they can do. Vibrations are a tough ghost to hunt down. Good luck.

[ezstriper]

I would take it to the local dealer and have them check the driveline angle. Compare to gm specs. Also can test drive with the eva2(electronic vibration analyzer) and see what they can do. Vibrations are a tough ghost to hunt down. Good luck.

 

I am going by my dealer this week....see if they have anything..have heard there was TSB on a rear spring issue..have a good working relationship with the local dealership..so stay tuned film @ 11

[70max]

i too have driveline vibration mine is from 58-65 and seems to be more of a growl mostly when ther is weight in the truck or towing a trailer i have spent 1200.00 and found nothing yet if you could let me know if you find anything my noise started to get worse when in 4wd replaced t-case was good for a little while then it got worse went through entire front end found nothing went to rear end and did u-joints hangar bearing and balanced drive shaft seem to get a little better but still there i think im goning to get a steelman chassis ear vibration tool for 269.00 no other ideas

[R Gage]

My buddy just replaced his support bearing. After he also had vibration around 35-45mph.He found out the shop somehow bent the spline end of the short shaft and had to have spline end replaced at a drive line shop. Just some info if it helps.

[70max]

anyone know anything about a dampner on the front of the rear pinion it is a rotating mass and i'm wondering if that could be my vibration i have seen pinion dampening that bolts on but not one thats between the yoke and the diff and rotates with driveshaft