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Transmission shudder by gold_pegasus87
Started on: 07-14-2014 01:41 AM
Replies: 16 (211 views)
Last post by: 84fiero123 on 07-16-2014 08:43 AM
gold_pegasus87
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Report this Post07-14-2014 01:41 AM Click Here to See the Profile for gold_pegasus87Click Here to Email gold_pegasus87Send a Private Message to gold_pegasus87Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hello my name is Evan and I'm brand new to the forum.

To start right off I picked up a 1987 fiero gt about 2 months ago with 58,801 miles on it. I purchased it from the second owner who only drove it about 500 miles in the 7 years he owned it. It's currently at 63,336 miles and I drive it every day for work. I've done a lot of work to the car since I bought it like;

Exhaust manifold gasket under the rear window
O2 sensor
New injectors
Distributor cap & rotor
plugs, wires, ignition coil
Ignition control module and pick up coil
Fuel pressure regulator
Fuel filter, air filter
PCV valve and cleaned EGR valve
And last but not least changed out the broken EGR tube.

After all is said and done the car runs flawlessly and quick, but I keep noticing a shudder that starts about 40mph and goes away at 50mph. I have checked everything. The rpms do not budge when the shuddering occurs and upon checking the Trans fluid it is right where it's supposed to be but has a couple tiny bubbles in it. What could I possibly be overlooking?
Thank you for any help you may have.
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OldsFiero
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Report this Post07-14-2014 07:48 AM Click Here to See the Profile for OldsFieroClick Here to Email OldsFieroSend a Private Message to OldsFieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
If there is air in the fluid, it can allow the TCC to slip. Change the trans filter. If the lining isn't to glazed up, it may fix it.
Marc
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84fiero123
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Report this Post07-14-2014 08:59 AM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
Have the tires balanced !
Smell the trany fluid if balancing the tires didn't work, if it smells like burnt almonds the trany clutches are toasted.
Steve

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Gall757
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Report this Post07-14-2014 09:24 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Welcome to the Forum!

123 is right.....and if the tires are over 10 years old you may want to change them anyway. Rubber compounds age and tend to wear unevenly.
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gold_pegasus87
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Report this Post07-14-2014 01:57 PM Click Here to See the Profile for gold_pegasus87Click Here to Email gold_pegasus87Send a Private Message to gold_pegasus87Edit/Delete MessageReply w/QuoteDirect Link to This Post
I just had the tires replaced 2 weeks ago. Went to have them balanced and found out they were 13 years old. I haven't tried smelling the fluid though, didn't think anything of it because it looked a nice reddish pink. When I first saw the bubbles I thought it could be a vacuum line but I don't think these cars have one for the trans.
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Report this Post07-14-2014 02:03 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gold_pegasus87:

I just had the tires replaced 2 weeks ago. Went to have them balanced and found out they were 13 years old. I haven't tried smelling the fluid though, didn't think anything of it because it looked a nice reddish pink. When I first saw the bubbles I thought it could be a vacuum line but I don't think these cars have one for the trans.


The shudder was the same before and after these tires?
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gold_pegasus87
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Report this Post07-14-2014 02:10 PM Click Here to See the Profile for gold_pegasus87Click Here to Email gold_pegasus87Send a Private Message to gold_pegasus87Edit/Delete MessageReply w/QuoteDirect Link to This Post
Yes. And it's not a consistent shudder that picks up and keeps going. It's just like a little jerk here and there that is sometimes worse or almost unnoticed. When it is happening though and you accelerate the torque converter thunks and unlocks then it goes away until it locks back up.
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Report this Post07-14-2014 02:21 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gold_pegasus87:

Yes. And it's not a consistent shudder that picks up and keeps going. It's just like a little jerk here and there that is sometimes worse or almost unnoticed. When it is happening though and you accelerate the torque converter thunks and unlocks then it goes away until it locks back up.


So the jerking could be a separate symptom from the tranny? I had a bad EGR cause that symptom on a 4 cyl car, though it was a 5 speed so I didnt have the tq converter to think about. It happened at a certain acceleration point, which in an auto could translate to a certain mph (as you said 40-50). A theroy: If you accelerate hard up to high speed if it doesnt do it at all, I might suspect the EGR somehow.

[This message has been edited by 2.5 (edited 07-14-2014).]

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gold_pegasus87
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Report this Post07-14-2014 02:26 PM Click Here to See the Profile for gold_pegasus87Click Here to Email gold_pegasus87Send a Private Message to gold_pegasus87Edit/Delete MessageReply w/QuoteDirect Link to This Post
Well like I said I cleaned up all the EGR valves and replaced the broken tube.
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Report this Post07-14-2014 02:31 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
I dont know if they can fail or wear out or stick even if cleaned out, perhaps.
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gold_pegasus87
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Report this Post07-14-2014 02:55 PM Click Here to See the Profile for gold_pegasus87Click Here to Email gold_pegasus87Send a Private Message to gold_pegasus87Edit/Delete MessageReply w/QuoteDirect Link to This Post
Guess I'll just have to go back and start double checking everything.
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gold_pegasus87
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Report this Post07-14-2014 04:07 PM Click Here to See the Profile for gold_pegasus87Click Here to Email gold_pegasus87Send a Private Message to gold_pegasus87Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by OldsFiero:

If there is air in the fluid, it can allow the TCC to slip. Change the trans filter. If the lining isn't to glazed up, it may fix it.
Marc


What lining would that be Marc? It seems like the filter might be my issue.
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trod84se4spd
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Report this Post07-14-2014 08:46 PM Click Here to See the Profile for trod84se4spdClick Here to Email trod84se4spdSend a Private Message to trod84se4spdEdit/Delete MessageReply w/QuoteDirect Link to This Post
had a problem similar to yours, turned out to TPS switch had a bad spot, AFTER $1200.00 trans rebuild
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gold_pegasus87
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Report this Post07-14-2014 11:50 PM Click Here to See the Profile for gold_pegasus87Click Here to Email gold_pegasus87Send a Private Message to gold_pegasus87Edit/Delete MessageReply w/QuoteDirect Link to This Post
It's not a dead spot in the pedal, I'm starting to think after changing all of fuel system parts my old fuel pump might not be able to keep up pressure at low rpm cruising speeds with the converter locked. I changed the transmission filter today and gained nothing. I also swapped out my cheap ignition coil for a better one and nothing has changed.

[This message has been edited by gold_pegasus87 (edited 07-14-2014).]

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Report this Post07-15-2014 09:19 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gold_pegasus87:

It's not a dead spot in the pedal, I'm starting to think after changing all of fuel system parts my old fuel pump might not be able to keep up pressure at low rpm cruising speeds with the converter locked. I changed the transmission filter today and gained nothing. I also swapped out my cheap ignition coil for a better one and nothing has changed.



The list of new parts on the top of the page, if it did not have this issue before them, I woudl suspect possibly one of them is faulty.
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OldsFiero
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Report this Post07-16-2014 07:33 AM Click Here to See the Profile for OldsFieroClick Here to Email OldsFieroSend a Private Message to OldsFieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
The lining I referred to is the paper lining on the converter clutch piston. You stated that the shudder is sporatic. TCC shudder is very rythmic(steady evenly spaced pulses). Sounds like a misfire for whatever reason. You have done all the obvious stuff. fuel pressure check is a good idea. It could be a lean fuel problem. Misfires often go away when the TCC unlocks and the load on the engine is reduced. It's got almost 60K on it, so change the trans filter anyway. It's time.
Marc
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84fiero123
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Report this Post07-16-2014 08:43 AM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gold_pegasus87:

Guess I'll just have to go back and start double checking everything.


this is an auto or standard? yes these auto tranys have a vacuum modulator valve that is run by vacuum that could create problems. I had one go on an early cutlass that stuck on the highway and actually sucked so much fluid out of the trany at highway speeds that it burned the trany clutches up and I didn't notice it because I was at highway speeds during a rain storm I didn't notice the smoke coming out the exhaust and until I reached a stop didn't realize anything was wrong.

Smell the trany fluid, and check the level.

Steve

[This message has been edited by 84fiero123 (edited 07-16-2014).]

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