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View Full Version : Pinion angle on truck with coils

Naked AV
01-31-2005, 06:12 PM
Lowered my Avalanche 2/3.5 and now I have vibration between 75 and 80 mph when accelerating. I've been told I likely need a 2 or 3 degree shim, but I've also been told that shims only work on trucks with leaf springs. What can I do to get rid of the vibration?
Beyond Static©
01-31-2005, 11:37 PM
Accelerating at 80mph? Isnt that speeding? haha, just messin. What type of suspension do they have in the back? coil or airbag? And yes, the pinion shims should only work with leaf springs.
Naked AV
02-01-2005, 12:41 AM
Bitchin' sig pic dude. :smokin:

I've got coils in the back...otherwise this would be a non-issue - I could get the shims and be done with it. But I've got coils.

So now what do I do!?!?
tony@air ride
02-01-2005, 07:59 AM
Your truck has a factory four link under it and should have maintained pinion angle dropping it the small amount that you did..... is it possible? yes... is it likely in your case.... no...... it is more likely that either your tires are out of balance or your tire and wheel combo is out of round........
Naked AV
02-02-2005, 08:30 PM
Umm, okay, I'll get the wheels and tires checked out. Anyone else have any ideas?
Davey
02-04-2005, 10:29 AM
Tony Knows His Stuff!!! Hum?.. Can You Say Dail Indicator?
Naked AV
03-02-2005, 03:22 AM
Alright guys, got new tires (even got them match-balanced wheels to tires) and the issue is still there. I went to a driveline shop and he said my angles were as follows:

1) Pinion: +7*
....(5* difference)
2) Driveshaft: +2*
....(2* difference)
3) Engine/Trans: +4*

I think this is the source of my vibration. HELP! What do I do? I think I need shorter upper control arms. Any ideas?
Toolman
03-02-2005, 03:45 AM
Bump.....Most quality kits take this into consideration with their kits. I would consult the manufacture if you do not get a response here. Just a thought....
Naked AV
03-02-2005, 04:30 AM
I contact McGaughys (who made the kit) and talked with the owner, Mike. What an *******. I told him about the angle measurements I got from the driveline place (that has been in business for almost 30 years, and took the measurements for me for free). He basically said that the people at the driveline place were morons. Once I told him how long the driveline place had been in business, and what exactly the measurements were, he acknowledged that there might be a problem, but refused to admit his kit could have anything to do with it. He said "I've sold thousands of these kits and no one has ever had a problem."

Nice experience.
Toolman
03-02-2005, 04:39 AM
I contact McGaughys (who made the kit) and talked with the owner, Mike. What an *******.

Nice experience.


Boy does that suck. I have not heard anything but good things about them. I hope that this can be worked out so that they wil not go down like Belltech did on the NBS kits.

If anyone can help the guys out, that would be great!!!!
Naked AV
03-02-2005, 04:46 AM
Yeah, I guess their products are good, but the owner is apparently a real piece of work who shouldn't be interfacing with the public. I've heard that they try to keep him away from the customers....now I see why. I was promised a call from the engineer who built the kit, but I didn't hear from him, so I called back and that's when Mike answered the phone. Maybe I'll try back again tomorrow.
Toolman
03-02-2005, 04:59 AM
Maybe I'll try back again tomorrow.

Yeah, that might be a good idea. Maybe someone will chime in and give you better direction.

Good luck,
mort
04-02-2005, 10:08 PM
Naked,

Did you ever get any help with your pinion angle problem?

I think you may find this link interesting. I got it of a post on LS1Tech.

Vibrate Software (http://www.vibratesoftware.com/html_help/html/Diagnosis/Reference/pinion_angle_changing.htm)

HTH :bowtie:
Naked AV
04-03-2005, 10:32 PM
Naked,

Did you ever get any help with your pinion angle problem?

I think you may find this link interesting. I got it of a post on LS1Tech.

Vibrate Software (http://www.vibratesoftware.com/html_help/html/Diagnosis/Reference/pinion_angle_changing.htm)

HTH :bowtie:
Yeah, thanks, I called and spoke with those guys - they're just as baffled with 4-links as everyone else....the only suggestions they had were for leaf springs. I'm going to a fabricator tomorrow to see if he can help me.