Town Car vibration only in overdrive at 70+ mph

[Kotagami]

Hey Guys,

i have a fairly new problem (couple of months) with my Town Car. When im on the Autobahn at around 70 mph upwards a vibration starts going through the whole car, like an on/off (breathing) ßvibration. At first i thought it would be my worn out tires (now have new tires) but today i went on the Autobahn again and disabled overdrive while having the vibration and it was gone, when i enabled overdrive the vibration started again. So it has to be related to the transmission or am i wrong ?

looking forward for some answers and thoughts. thanks in advance.

 

[lenmar2c]

I believe what you need to do is drain and refill your torque converter. Some torque converters have a drain and some do not.

 

[driller]

...disabled overdrive while having the vibration and it was gone, when i enabled overdrive the vibration started again.

NVH issues are difficult to isolate, especially so over the internet. Pure guess on my part, but I would say that indicates an issue with the OD band in the transmission?

 

[oktowncar]

Universal joints, transmission mounts, OD band as mentioned above could be the culprits to look at

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[Kotagami]

alright, thanks guys. I will order two new U-joints and the transmission mount and do them on the weekend. its leaking a bit fluid from the tranmission housing anyways so im going to replace the seal aswell. imma get back to you guys when im done.

 

[Action]

You might inspect the U-joints to see if there is play, and the same for the transmission mount.
Replacing parts that are not bad, to still have the problem is a bit frustrating and expensive.

Both of those items have nothing to do when the OD is engaged or disengaged. Not to say those items are questionable. But doing some inspections/diagnosis first might be prudent. As there are other areas that can cause NVH concerns besides those.

Inspect the engine mounts. Move the engine and transmission with a large bar to see what kind of movement is displayed.
Raise the vehicle and check the (tire/wheel assy) wheel bearings for excessive play.

Disabling the OD at speed increases engine RPM.
Does that mean the vibration is limited to an RPM range?
An RPM range that requires vehicle speed too?
Installing (temporarily) a tachometer to understand the engine RPM that the vibration occurs might yield some good information.

Another diagnostic thing you might do is to drive to the speed that the vibration is worst. Then accelerate a little higher and take your foot off the accelerator and shift to neutral. Is the vibration still felt?

Other questions would be:
How many miles on your Town Car?
Is the wheels and tires stock? If no what are they?
When did this issue show up? In time and miles.
Did it get progressively worse over time? Or was it noticed all of a sudden?

Action

BTW, is that a one fingered hand gesture in your avatar?

 

[ogre01]

No being a paid supporter of the forum, I'll mostly keep mum, but I think OP is a bot farming responses for whatever reason.

 

[driller]

No being a paid supporter of the forum, I'll mostly keep mum, but I think OP is a bot farming responses for whatever reason.

AI learning?

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[ogre01]

AI learning?

Yes, don't know why necessarily, but certainly to fine-tune question/response interactions. At some point it will be extremely hard to tell the difference.

I wish we could upload audio files. I got a bot voicemail at the office yesterday and frankly it was nothing short of incredible; language, "pauses", enunciation etc. all spot on, with a well designed, convincing message to boot.

Ridiculous, problematic, impressive. Makes me glad to be a hardcore gen X luddite.

 

[oktowncar]

AI learning?

Apu in Kolkata is earning a few rupees