[thepunkerguy]

Ok, well for the last 8 months i have been trying to fix a start off shudder that i just can't seem to get rid of no matter what i try. Here is what all i have tried:

- measured and set drive line angles to make sure they were correct
- made sure those angles make my u-joints phase properly
- checked my 3link for play in the bushings
- got my drive shaft re-tubed and balanced because of a ding in it
- got all new u-joints installed
- installed a new factory center support bearing
- made sure there was room for both parts of the driveshaft to slide front to back a little
- made sure the shafts arent binding at all in full range of motion

Bascially i have a sd.com super pivot 3-link installed with F9000 bags and rear shocks. My truck is a '98 ext cab with a v6, 5spd, and 2 piece drive shaft (NO double cardon joints, just regular u joints). I have shims under the tranny and center support bearing. I really dont know what else to try here. My problem is that from start, through first gear until around 25-30mph i get a bad start off shudder. I can feel it really holding the truck back and its VERY annoying, i am sure its not good for the truck either. The weird thing is that when i lift up the back of my truck all the way the shudder pretty much goes away. The farther i go down the worse it gets. From all indications it would make sense that its the drive-shaft angles or pinion angle, but my angle finder says they are fine. The only other thing i can think of is that something in the back does have some play in it that i can feel by hand and that when i lift up the truck all the way in the back that the bags put pressure on whatever is loose and makes the shudder go away. I dont think it could be a clutch or flywheel problem since it goes away when i lift up the back of the truck. I dont know, but i am ssssoooooo tired of dealing with this problem, i have worked on it every weekend for months now and just dont seem to get anywhere. Does anyone have any ideas at all? Know any good shops that could look at this kinda problem on a modified truck in FL? At this point i just want it fixed! Let me know.. thanks guys.. sorry for the long post
- Mike

 

[pack of q tips]

clutch?

 

[thepunkerguy]

clutch?

I thought about that too, but if it was clutch or flywheel it wouldnt go away when i lifted up the rear of the truck ya know? Not to mention i only got 80k miles ont he clutch / truck and it still grabs really well.. hmm..
- Mike

 

[bigjsp]

If you have adjustable links, reset the angle at normal ride height to what is you think is the smoothest at the high height and try it.

 

[lowdime96]

Sounds like your dog legging....AKA the axle isn't parallel to your from wheels and you have a longer wheel base on one side than the other side. the rear end is fighting the front end in an attempt to go straight. Try turning your steerring wheel at start off about 10 degrees in either direction to see if excelleration is improved. Also check your rear fenders to see if one of your rear wheel is off center in the fender. Also, if you didn't get the front end aligned in a long time you can try that as well.

 

[SlammedDime]

See if you can do this... get a small tape recorder, or small video camera, and record the sound. If you can get a friend to sit in the bed with a video camera aiming down through the bed at the drivetrain. Get it as low as possible, get as much as you can... Don't drive too fast, just enough to get a clear video and sound of whats going on.

You're sure that the driveshafts aren't hitting anything? I know I've beat that to death, but I had the exact same problem, and it sounds like you are describing the sound to a T, and when I looked under my truck, my first shaft was hitting the bottom of the cab. All check and see if perhaps the transmission is hitting the cab. I don't know that it would create a chatter type sound, but its something to look for.