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thud on take off

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Old Sep 9, 2008 | 07:50 AM
  #1  
dunnellon86's Avatar
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From: florida
Car: 89 firebird
Engine: 2.8 mpfi
Transmission: 700r4
Axle/Gears: stock
thud on take off

ever since i had to swerv to miss an armidillo my car has been macking a nasty thud on hard takeoffs only on the passenger side if i slowley come out of a stop no noise but if i floor it boom, eny ideas i took the tire off and did a visual inspection and everything seems fine but i dont know thanks
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Old Sep 9, 2008 | 08:08 AM
  #2  
TexasSilhouette's Avatar
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From: Colorado
Car: 1991 TransAm GTA 350
Engine: 350 SBC TPI
Transmission: 700R4
Re: thud on take off

Transmission mount. When broken the torque arm pushes the transmission up against the floor pan.
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Old Sep 9, 2008 | 08:14 AM
  #3  
heat seeker's Avatar
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From: Austin TX
Car: 89 Formula
Engine: 383 SBC/HSR
Transmission: 700R4
Axle/Gears: 3.73
Re: thud on take off

Yep, that's it.
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Old Sep 9, 2008 | 09:30 AM
  #4  
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From: florida
Car: 89 firebird
Engine: 2.8 mpfi
Transmission: 700r4
Axle/Gears: stock
Re: thud on take off

is this it?
http://www.partsamerica.com/productd...ype=38&PTSet=A
and its located right were the the tranny meets the drive shaft right?
and when i do a visual isspcetion what do i lok for on the old one to see if it is bad?
thanks
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Old Sep 9, 2008 | 09:43 AM
  #5  
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From: Madison, WI
Car: 1986 Camaro Z28
Engine: 400
Transmission: T5
Axle/Gears: 10 bolt Posi 3.73
Re: thud on take off

This is the part you need.
http://store.summitracing.com/partde...5&autoview=sku

I would recommend the poly mount. It is stronger and wont tear like the crappy rubber one you had.

And yes, it's the brace that goes across the subframe and the transmission tail rests on it.

Here's how to fix it/identify if it's broken. (This excerpt can be found in the Tech section. Thanks to Drew for the write up. https://www.thirdgen.org/trannymount)

"This article will step you through the removal and installation of a transmission mount.

Using a Poly mount is recommended. However it can cause more vibrations to be transferred to the car. Additional complications can arise with a poly mount due to its size being slightly out of spec.

Further conflicts can occur with sub-frame connectors and the poly mount.

After doing one tranny mount, doing it in the future shouldn’t take more than 15 minutes.

1. Raise and support the car with jack stands.
Codename 47's EDIT: Try to look at the transmission mount now before you rip everything apart. You might be able to identify if it's broken.
2. Remove the 15mm nut from the tranny mount stud.
3. Use a 2x4 at least the width of the transmission pan on top of your jack and raise the transmission a few inches.
4. Remove the two 14mm bolts from the mount to the transmission.
5. Remove the mount, if it can’t be removed raise the transmission higher and try again.
6. Install the new mount using the original 14mm bolts to the transmission and either the supplied cross member to mount bolts or the original 15mm bolt.
7. Torque the bolts to spec.
8. Return the car to the ground and go for a drive.
"
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Old Sep 9, 2008 | 10:21 AM
  #6  
dunnellon86's Avatar
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From: florida
Car: 89 firebird
Engine: 2.8 mpfi
Transmission: 700r4
Axle/Gears: stock
Re: thud on take off

[quote=Codename 47;3882601]This is the part you need.
http://store.summitracing.com/partde...5&autoview=sku

so the one i was looking at is not the right one and wont work or are thay the same?
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Old Sep 9, 2008 | 11:39 AM
  #7  
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Re: thud on take off

Get the rubber OE replacement. Too many cars with weird vibrations running that poly mount. I'd avoid it.
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Old Sep 9, 2008 | 04:27 PM
  #8  
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From: Madison, WI
Car: 1986 Camaro Z28
Engine: 400
Transmission: T5
Axle/Gears: 10 bolt Posi 3.73
Re: thud on take off

Originally Posted by dunnellon86
so the one i was looking at is not the right one and wont work or are thay the same?

Just go to your local parts store and they will have the stock rubber one. Tell them the year/make/model of your car and they well get it for you.
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Old Sep 11, 2008 | 06:37 AM
  #9  
dunnellon86's Avatar
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From: florida
Car: 89 firebird
Engine: 2.8 mpfi
Transmission: 700r4
Axle/Gears: stock
Re: thud on take off

ok well got the part and put the new one on and no more banging thanks
what was macking the noise was it the pan hitting the cross member or what?
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Old Sep 11, 2008 | 07:31 AM
  #10  
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From: Colorado
Car: 1991 TransAm GTA 350
Engine: 350 SBC TPI
Transmission: 700R4
Re: thud on take off

The transmission hitting the floor of the car. Torque arm lifts the trannsmission.
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Old Sep 11, 2008 | 09:36 AM
  #11  
dunnellon86's Avatar
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From: florida
Car: 89 firebird
Engine: 2.8 mpfi
Transmission: 700r4
Axle/Gears: stock
Re: thud on take off

ok good to know thanks
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