Is drivetrain centered on F-body?
08-31-2009, 08:10 AM
#1
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Is drivetrain centered on F-body? Hello
Is the transmission output shaft and the rear axle yoke suppose to be centered on F-body. I have recently had motor/transmission poly mounts installed and have vibration @ 70mph, my original tranny mount is shot, so while I am waiting for the factory one I got under the car and it looks like transmission is slightly to the right and rear axle is to the left off center. Before I go buying adjustable panhard rod and move / recenter the transmision I want to know is the drivetrain suppose to be centered in our cars. The car drives straight and does not pull. The car is stock w original rims/tires
Is the transmission output shaft and the rear axle yoke suppose to be centered on F-body. I have recently had motor/transmission poly mounts installed and have vibration @ 70mph, my original tranny mount is shot, so while I am waiting for the factory one I got under the car and it looks like transmission is slightly to the right and rear axle is to the left off center. Before I go buying adjustable panhard rod and move / recenter the transmision I want to know is the drivetrain suppose to be centered in our cars. The car drives straight and does not pull. The car is stock w original rims/tires
08-31-2009, 06:09 PM
#6
However, since the lateral (side to side) movement of the rear axle is determined by the arc of the panhard bar, the position of the rear axle, with respect to the unit body, varies with the ride height.
(that's why the question, "Is the car lowered" was asked)
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08-31-2009, 09:41 PM
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More info + pictures Thank you gentlemen for your quick responses.
I am looking for some concrete evidence on the location of the drivetrain, maybe they mention something in Factory Service Manual... unfortunately I don't have one yet. I will try to include pictures which show why I suspect the rear end is not centered.
In the pictures the driver side rear wheel seems be further out then pass side. Also note the rubbing spot seen in the right wheel well. Since I bought the car it is rusting, so not rubbing yet. The car has never been lowered because I bought it from the state, so it is very low chance that police was riding on dubs or lowered the car :-) , however they possibly did crash/spin out. Non the less body show no evidence of a crash.
I had motor mounts installed in the shop, so I don't know how it was located originally, plus the transmission mount was completely torn apart. Polyurethane transmission mount has locating slots, so it is quite possible to install it incorrectly, especially after technicians were fed up the the motor mounts.
I had the car on a lift briefly to inspect their work and after taking quick measurements nothing seemed centered. I did not have enough time to write down the exact numbers.
So in conclusion I possibly have two problems I need to solve:
1. Rear axle not centered, from previous damage.
2. Transmission output shaft is not centered after transmission mount replacement.
Possible solutions:
1. Adjustable panhard rod.
2. Loosen the mount apply pry bar until centered.
Sorry for the long post but I want to be well informed and not waste money when I go back to the shop to center transmission and get wheel alignment.
I am looking for some concrete evidence on the location of the drivetrain, maybe they mention something in Factory Service Manual... unfortunately I don't have one yet. I will try to include pictures which show why I suspect the rear end is not centered.
In the pictures the driver side rear wheel seems be further out then pass side. Also note the rubbing spot seen in the right wheel well. Since I bought the car it is rusting, so not rubbing yet. The car has never been lowered because I bought it from the state, so it is very low chance that police was riding on dubs or lowered the car :-) , however they possibly did crash/spin out. Non the less body show no evidence of a crash.
I had motor mounts installed in the shop, so I don't know how it was located originally, plus the transmission mount was completely torn apart. Polyurethane transmission mount has locating slots, so it is quite possible to install it incorrectly, especially after technicians were fed up the the motor mounts.
I had the car on a lift briefly to inspect their work and after taking quick measurements nothing seemed centered. I did not have enough time to write down the exact numbers.
So in conclusion I possibly have two problems I need to solve:
1. Rear axle not centered, from previous damage.
2. Transmission output shaft is not centered after transmission mount replacement.
Possible solutions:
1. Adjustable panhard rod.
2. Loosen the mount apply pry bar until centered.
Sorry for the long post but I want to be well informed and not waste money when I go back to the shop to center transmission and get wheel alignment.
09-01-2009, 07:00 AM
#9
"Gramozeka", you got me curious, so I went out to the garage and looked at my car....
I have a '96 Z-28, lowered with Eibach springs, poly engine and tranny mounts, and an adjustable panhard bar. I'm the original owner of the car, so I know it's history.
The one thing that you have to consider is that your Camaro's rear axle is located laterally by the panhard bar, which travels in an arc. You mentioned that you checked the car while on a lift. Was the lift a "drive on" lift, where the weight of the car was on the suspension, or a lift where the rear axle "hung down"?
If the rear axle was "hanging" when you looked at the car, the axle would have "shifted right", toward the passenger side, as the panhard bar is attached to the chassis on the right side, and as the axle dropped and pivoted, it moved to the right.
On my car, the drive shaft looks fairly well centered, or in other words, perpindicular to the tailshaft of the transmission. However, it's easy to get confused, as the eye's natural tendency is to make comparisons to the surrounding objects. Under the car, you have the driveshaft, the torque arm, the exhaust pipes, rear trailing arms, and transmission tunnel, ALL going in the same direction. Visually, you're trying to focus on the driveshaft, but there's a LOT of other stuff that can distract you.
Also, I've observed a lot of Camaros and Firebirds over the years (they've used the same rear suspension design since '82), and no two seem to sit at the exact same ride height. The factory, however, uses only one panhard bar for ALL applications, so that means that there are a lot of cars out there with their rear ends a little "off center"....
I have a '96 Z-28, lowered with Eibach springs, poly engine and tranny mounts, and an adjustable panhard bar. I'm the original owner of the car, so I know it's history.
The one thing that you have to consider is that your Camaro's rear axle is located laterally by the panhard bar, which travels in an arc. You mentioned that you checked the car while on a lift. Was the lift a "drive on" lift, where the weight of the car was on the suspension, or a lift where the rear axle "hung down"?
If the rear axle was "hanging" when you looked at the car, the axle would have "shifted right", toward the passenger side, as the panhard bar is attached to the chassis on the right side, and as the axle dropped and pivoted, it moved to the right.
On my car, the drive shaft looks fairly well centered, or in other words, perpindicular to the tailshaft of the transmission. However, it's easy to get confused, as the eye's natural tendency is to make comparisons to the surrounding objects. Under the car, you have the driveshaft, the torque arm, the exhaust pipes, rear trailing arms, and transmission tunnel, ALL going in the same direction. Visually, you're trying to focus on the driveshaft, but there's a LOT of other stuff that can distract you.
Also, I've observed a lot of Camaros and Firebirds over the years (they've used the same rear suspension design since '82), and no two seem to sit at the exact same ride height. The factory, however, uses only one panhard bar for ALL applications, so that means that there are a lot of cars out there with their rear ends a little "off center"....
09-04-2009, 06:59 AM
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leadfoot4 thanks for your explanation, if all cars sit at different level from the factory it makes me less worried.
I have to do some work under the car so this weekend I will get under and make more exact measurements with rear axle off the ground and supported by jackstands.
Thanks all.
I have to do some work under the car so this weekend I will get under and make more exact measurements with rear axle off the ground and supported by jackstands.
Thanks all.
