Driveline vib, driveline angle measurements inside, help!
#1
Driveline vib, driveline angle measurements inside, help!
I'm trying to track down a driveline vibration that occurs at highway speed, usually 65mph+ and gets worse as you go faster. I just checked all driveline angles with a magnetic angle finder and have the following info:
Transmission angle: 3.5 deg downward
Pinion angle: 1 deg upwards
Driveshaft angle: 1 deg sloping downward from trans to rear pinion.
I am running a 4l80e trans with holley crossmember and a poly mount. 4th gen rear with a brand new custom steel balanced driveshaft.
Do these angles look ok? The holley crossmember has adjustment in the torque arm that will change pinion angle if needed. Any help would be great!
Transmission angle: 3.5 deg downward
Pinion angle: 1 deg upwards
Driveshaft angle: 1 deg sloping downward from trans to rear pinion.
I am running a 4l80e trans with holley crossmember and a poly mount. 4th gen rear with a brand new custom steel balanced driveshaft.
Do these angles look ok? The holley crossmember has adjustment in the torque arm that will change pinion angle if needed. Any help would be great!
#2
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,040
Received 1,668 Likes
on
1,266 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Driveline vib, driveline angle measurements inside, help!
No, not really OK...
Ideally you want the trans and the pinion at the same angle. I.e. if you drew a straight line through each, the lines would be parallel. Yours are not.
If you can raise the front end of the torque arm, that's the direction the pinion needs to go. About 2½° or so. Maybe just a bit less, ½° maybe, so that when engine torque does what it does, which is to raise the pinion slightly, they're parallel when powered.
Ideally you want the trans and the pinion at the same angle. I.e. if you drew a straight line through each, the lines would be parallel. Yours are not.
If you can raise the front end of the torque arm, that's the direction the pinion needs to go. About 2½° or so. Maybe just a bit less, ½° maybe, so that when engine torque does what it does, which is to raise the pinion slightly, they're parallel when powered.
#4
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,040
Received 1,668 Likes
on
1,266 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Driveline vib, driveline angle measurements inside, help!
You could try that; I guess it would depend on how much tunnel clearance you have. I doubt it would be as effective as adjusting the rear's angle though. Try the correct, designed-in approach first.
#6
Re: Driveline vib, driveline angle measurements inside, help!
adjusted the mount to its max setting and ended up with the following angles:
Transmission angle: 3.5 deg downward
Pinion angle: 2 deg upwards
So i gained one degree by adjusting my torque arm mounting position on the crossmember. Took the car for a quick spin and it felt better, but will have to get some highway miles logged to really tell.
Getting an alignment tomorrow, may try to put some miles on after I get it back.
Transmission angle: 3.5 deg downward
Pinion angle: 2 deg upwards
So i gained one degree by adjusting my torque arm mounting position on the crossmember. Took the car for a quick spin and it felt better, but will have to get some highway miles logged to really tell.
Getting an alignment tomorrow, may try to put some miles on after I get it back.
#7
Supreme Member
Join Date: Jun 2005
Location: huntsville, al
Posts: 1,440
Likes: 0
Received 0 Likes
on
0 Posts
Car: 89 IROC
Engine: 6.8 HSR N2O
Transmission: TKO 600
Axle/Gears: 9" Moser 3.50 True trac
Re: Driveline vib, driveline angle measurements inside, help!
No, not really OK...
Ideally you want the trans and the pinion at the same angle. I.e. if you drew a straight line through each, the lines would be parallel. Yours are not.
If you can raise the front end of the torque arm, that's the direction the pinion needs to go. About 2½° or so. Maybe just a bit less, ½° maybe, so that when engine torque does what it does, which is to raise the pinion slightly, they're parallel when powered.
Ideally you want the trans and the pinion at the same angle. I.e. if you drew a straight line through each, the lines would be parallel. Yours are not.
If you can raise the front end of the torque arm, that's the direction the pinion needs to go. About 2½° or so. Maybe just a bit less, ½° maybe, so that when engine torque does what it does, which is to raise the pinion slightly, they're parallel when powered.
Trending Topics
#8
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,040
Received 1,668 Likes
on
1,266 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Driveline vib, driveline angle measurements inside, help!
trans is angled toward the ground, the driveshaft is almost level and the rear points up
All of that of course, with the car sitting on a level surface, with the suspension at normal ride height... doing this on ramps with somebody about your size sitting in the driver's seat, somebody else about your SO's size in the pass seat, and a full tank of gas, is a great way to get that part right.
Thread
Thread Starter
Forum
Replies
Last Post
6speedIROC
Transmissions and Drivetrain
1
08-17-2016 09:39 PM
87LB9B4Z
Tech / General Engine
1
03-22-2002 09:50 AM
Steves ZZ5
Tech / General Engine
4
01-18-2001 12:46 PM