How to check auto trans mount on 2005 4.0L

[Spence340]

Picked up a vibration a while ago and it seems to be getting worse. After searching the site I am thinking maybe the transmission mount might be gone or maybe the engine mounts. Can you see the that the mount is gone by jacking up the car and taking a look with a flashlight? My car has 110,000 miles on it and the only mod is a dual exhaust system with GT mufflers.

 

[86GT351]

For Engine Mounts, Have someone power brake and you will see one side or the other lift if they are weak or compromised. For the transmission mount, Get under vehicle and see if you can move the transmission up and down.

 

[Joe combs]

I would be looking at the driveshaft carrier bearing setup....the 2 piece driveshaft's are known for problems....

 

[Spence340]

I will check those two ideas and I should mention the vibration is most noticeable at idle sitting in traffic or at a light.

 

[Joe combs]

if it is at idle... is it more of a misfire type of vibration? The other known problem with the 4.0 is harmonic balancer failure, which could cause a vibration. When was last time car was tuned up with new plugs and wires?

 

[Spence340]

Car has not been tuned up forever so I suppose I could start with plugs etc. It's funny you mention harmonic balancer failure as I was just thinking the other day that's what it feels like. How much of job would that be to replace on these cars and is there any way to tell if it is actually gone?

 

[DieHarder]

If you put the car in park while waiting for the light does the vibration go away? If so, that's what my son's car does... v6. Upgraded the exhaust to dual; lessened the vibration quite a bit. I believe what happens is idling with the transmission in Drive with the brake on sets up harmonics which results in noise from the exhaust. I've seen quite a few v6's with extra weights welded on the exhausts in an effort to reduce NVH.

Another thing I've found is changing out the spark plugs and replacing the spark plug wires improved idling a lot (much smoother now). You might try that as well.

Don't believe it's a harmonic balancer. If it fails you'll know it. The racket it makes will wake the dead/ (neighbors...).