well when i accelerate i hear a loud knocking in the rear off my car. it doesnt do this when i'm at a light and my foots on the brake. is it in my rear-end or tranny, i know its not my engine. thanks for all the help

 

I'd guess it's the trans mount. Does it sound like it's around your butt? Get under the car, and try to bench-press the back end (tailshaft) of the transmission up to the sky. You don't need to be Arnold Swartzenegger to do this.. if your trans mount is busted, you'l be able to pivot the trans up to the floor board. If it's fine, you won't be able to budge the trans at all. Stock replacements are $15 at a parts store- and will probably break again in a few years. Or, you can buy a polyurethane (undestructable) trans mount by Energy Suspension for $25 from http://www.summitracing.com - give them a call.

One thing to check that happened to me.. with the car off, see if the back of the driveshaft is smacking the exhaust pipe.

(I did a 3.73/posi/disc axle swap and never re-checked the torque of the bolts. I lost a bolt in the panhard rod, which caused the rear to sway left-to-right, which caused the d-shaft to smack the hell out of my exhaust pipe! I found the bolt in front of my neighbor's house.. the nut was long gone.)


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

well i dont think it's the trans mount. i busted one of those in my firebird so i know the sound and this is different. but it could very well be the drive shaft thing. i'll have to get under my car and look. but i'm not that much of a mechanic. anybody else have some other suggestions??

 

Check all the bolts on the rear suspension pieces. I had a similiar problem and it turned out that a few of the bolts had vibrated loose and were causing movement.

 

Try checking the rear sway bar endlinks too....I had a bump in the back of my car and it took me a month to finally locate it.

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Riccioli Performance Motorworks

--RPM Racing--

-Currently building first ever engine. 383 with Super Ram plenum and runners, Edelbrock lower intake, Bosch 24# injectors, either AFR or Trick Flow heads, MSD ignition.
-Will be installing Baer Brakes
-Will be installing full Spohn suspension in rear
-Art Carr 700R4 trans??


***** Flyby: (n) When you let off the throttle after beating a ***** Racer by a few car lengths and he then blows by you in an attempt to convince you he really won the race.

 

thanks for your help guys i'll look at it tomorrow and see what i come up with

 

I just had to replace my torque arm. It was cracked just in front of the rear axle on the top and bottom. I bought a 85 Z28 torque arm from a fellow club member for $10 and put in a energy suspension torque arm mount. Big difference. Let us know what you find out.
Craig

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84 Z28 305HO, 5spd, 220,000 miles, Edelbrock intake, Hedman headers, low restriction exh(w/cat), K&N air filter. Best 1/4 so far 14.649 at 94.77mph

 

David,

Don't forget to get a good look at the torque arm and lower control arm bushings, track bar and brace, and shock mounts. Check the bushing at the front of the torque arm AND the bolts at the differential housing.

It's unlikely, but check the springs in case one of them is cracking near an end coil.

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Later,
Vader
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"I cannot take this any more... Saying everything I've said before..."
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[This message has been edited by Vader (edited January 08, 2001).]