Automatic Transmission/Driveline "clunk"

[SIMV]

This is a post that I made over at MustangForum.com and got not much of a response. I was kinda hoping that you guys here would have a little more info. Thanks for looking.

Alright guys, I went all the way back to page 12 and didn't find anything about this, so if it's been covered before I apologise.

I just bought a 2002 Automatic Gt with a shaker hood, ram air, 75mm throttle body, UDP's,superchip. 3.73 gears, X-pipe, and Magnaflow exhaust. I know I'm forgetting some stuff, but the upgrades are irrelivent... I just wanted to give you guys some background on the car.

Recently I noticed that when driving in overdrive and coasting at low speeds (usually 35 and below) it seems like the transmission doesn't know what gear it want's to be in and jerks a little bit. Sometimes it's so bad that it feels like the tail end of the tranny and the driveshaft is bouncing off the bottom of the car. What is the problem? Is this a common thing with GT's? Or should I book the first appointment to my local mechanic?

 

[mikes2008gt]

I've never heard of that specific problem, but it sounds like the u-joints are worn out.

Welcome to :SNSign: btw.

 

[streetstang03]

clutch packs possibly...how many miles on the car?

 

[bham_gt]

I've got a 2003 automatic that seemed to act very similar to the way you describe yours. It eventually got so bad that it shuddered really bad when shifting into and out of overdrive. I took it to the dealer and they changed the transmission fluid and that cleared the shuddering right up. Sometimes it still "jerks" a little bit when going low speeds in overdrive, but not nearly as bad. You might want to get your fluid and filter changed though if you haven't had it done.

 

[sneakygt]

I have an 01GT auto. 32k miles. Same situation and like bham gt did, I changed the fluid and filter and it pretty much cleared it up. It still chugs a little bit right at 33 mph.

 

[Kilgore Trout]

With auto tranny always start with that which is cheapest and easiest, change the fluid and filter.

 

[PEWTERPONY]

They clunk if you don't get the fluids changed every 30k.

 

[SIMV]

Interesting... I just turned over 30k too. Good idea on starting with the cheapest. I was real close to buying new motor and trans mounts.

 

[Dark Knight GT]

Sounds like a torque converter shudder to me. How many miles, and what kind of condition is the transmission fluid in ? Have you had a flashing o/d light to appear on the dash ?

 

[SIMV]

I just turned 30k, and I just bought the car about a month or two ago, so I don't know about the trans fluid.

 

[Dark Knight GT]

Chances are, the fluid hasn't been changed in it. I would say give the transmission a flush with fluid and filter change.

 

[TGJ]

First thing, change/flush tranny fluid with mercon V.

 

[PEWTERPONY]

SIMV...30K You got time to change it. I hear that if you let it go way to high milage, the tranny will act weird after you have taken the fluid out and put new in.

I get mine changed every 30k