I have noticed the same vibration on my '01. However it seems to be a noise not a shake. This is noticeable at about 90-95mph range only. Could it be a result of the larger aluminum drive shaft? In all reality it does not bother me because I am rarely going 90-95.

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2001 RED Adopted 2/10/2001 at 11:00am
Bed Rug
Retrax cover (sweet unit)
(Waiting on chip availability)

V 1

 

we have a 330 cid engine in our 98 Expedition, and this engine is smooth as silk all through the RPM range. Sitting still in park 500 to 5500 rpm, you can hardly tell the engine is running (save for hearing it.) Same total lack of vibration from 0 to top MPH. Folks, someting is WAY WAY left of center with these Blown 330 inchers!!!

J.

 

Here's a couple of tips from someone who had the vibration on the 99 cobra that couldn't be cured take it FWIW.
1)Note the speed that the vibration occurs. Accelerate past that speed and, in neutral, coast back through that speed with the engine idling. If the vibration is still there, it's not the engine or accessories.
2) If it's not the engine...drive at the vibration rpm in different gears. If the vibration is still there, at the same rpm in every gear, it could be the torque converter. If it only happens in certain gears, Factory_Tech may be able to share some expertise on the tranny's innards; but it would be the tranny.
3) If it's none of the above, usually rearend and suspension vibrations only occur at a set speed range, and sometimes at a harmonic speed above or below. A narrow band indicates u-joints or driveshaft, since they will pass through their harmonics 3.73 times faster than the diff or suspension.
4) If it is the engine, remove the accessory belt and go for a SHORT drive at the indicated rpm. (eat your wheaties first, those 295s will need some muscle to turn). If the vibration is still there at the same rpm, it's the engine, supercharger, motor mounts, tranny mount, or exhaust.

My guess from what you describe would be loose/bad engine accessory or motor mounts. If it was the torque converter, I would think it would vary under full throttle vs light load.

 

Oh sure, when I got my truck last year I went through all of this and all I got for responses was that everybody's engine and drivetrain was smooth as silk. Sounds like there's a little more to the story. I was told by my service tech that it was a truck after all. Blow me. And you don't get my business anymore either!!!

Hopefully my '01 is better tomorrow. We'll see.

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2000 Red Lightning - #835 of 4966 Born 3-8-00 / Delivered 3-22-00
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Best time: 13.45 sec. @ 101.99 mph

2000 Red Trans Am Ram Air WS6, 6 Speed - Delivered 2-15-00 - Awesome Looking Car

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Sounds like a loose blower pulley adapter. Just change mine to a larger crank pulley and the factory adapter was loose. No vibration with new pulley.

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2000 Silver Lightning 13.82 (stock)
PSP 4-way
PSP Filter Kit
PSP Lower Pulley
Level 10 Shift kit
Snug-Lid
In the works:
Level 10 converter
4-Link