engine and drivetrain Transmission Sitting Off Center

[Grover]

For as long as I've had my car, the transmission has sat slightly off center in the tunnel. Basically, it sits about 1/2" closer to the driver's side of the tunnel than the passenger side. I'm in the midst of replacing the guibo and a couple of other odds and ends down there, and I'd like to see if I can resolve this issue at the same time. The motor mounts are new and this hasn't changed how the tranny/engine sit, and I don't see any opportunities to twist the motor via elongated mounting holes for the motor mounts or anything. Is there a way to ever-so-slightly twist how the motor sits in its mounts? I can "pull" the tranny centered via the mounting bracket, but given that it isn't where it wants to sit naturally, I'm inclined to think this will just cause wear somewhere else. Thanks in advance.

[Conserv]

Does your car exhibit symptoms of problems this off-center trans may be causing, e.g., noises, shifting issues, premature wear of driveshaft components?

Steve

[jimk]

I'd check the trans output flange to driveshaft flange parallelism.  If they are parallel side to side,all is ok. If the trans is moved sideways, they will be out of alignment.  Move the trans only to get the parallel aiignment.  The center bearing does not have side to side adjustment to fix an out of paralel aiignment at the transmission.  The vertical alighment of the flanges are to be parallel also.

[M3M3]

my tranny is slammed all the way against the drivers side of the tunnel.  it does not have to be centered.  these cars are old and had large production variances....they are not all the same.    tranny has to be where it needs to be to get the tranny and front half of driveshaft aligned vertically and horizontally.  that is all that matters.  

 

JimK....the center bearing DOES have side to side adjustment.  the holes are slotted.  at least the last one i installed did.

Edited June 17, 2013 by mlytle

[Grover]

Thanks guys. The only sign of ill side effects I see is that my guibo is showing cracks after just being in there about two years. Whether this is a direct result of the transmission sitting off center or not, I don't know. I will follow the advice to see if I can confirm that the output shaft and driveshaft are perfectly aligned, and see where to go from there.

[M3M3]

guibo crack has nothing at all to do with tranny being offcenter.  that is either from age or your tranny/drivshaft alignment is off.

[Grover]

The guibo is no more than 2 or 3 years old so I don't think that is the issue. My thinking was that if the tranny was not properly centered in the tunnel, this could result in poor alignment of the tranny to driveshaft.

[williamggruff]

The motor can be aligned, and with it, the transmission. The passenger's side motor mount bracket allows for a bit of forward/backward adjustment. If you keep the driver's side mount fixed, moving the passenger's side motor mount forward relative to the subframe will rotate the motor counter clockwise when viewed from above. This will move the trans toward the passenger's side of the tunnel. However, it will also adjust the alignment of the driveline toward the passenger's side, which might be problematic unless your driveline is currently aimed toward the driver's side. Ideally, you want the motor and trans aligned with the diff, with the center bearing directly in line between them.

You can also adjust the alignment of the motor via the driver's side motor mount. The forked flange on the front subframe that holds the motor mount is angled so that the top of the fork is rearward of the bottom of the fork. By securing the motor mount at the bottom of the fork, the motor and trans are aimed toward the driver's side of the car. Moving the mount upward will shift the motor/trans alignment toward the passenger's side. Again, the goal Is to get alignment of the entire driveline, not just get the trans in the middle of the tunnel.

You can also shift the motor and trans laterally by using a thicker or thinner driver's side motor mount.

Several options, all of which should be carefully implemented to ensure proper alignment of the driveline.

Edited June 17, 2013 by williamggruff