Vibration Need Help

Walt92Conv · 07-03-2002, 07:08 AM

I am looking at buying a 92 GT convertible.

In fifth gear there is a lot of vibration. If I shift back to fourth and maintain speed the vibration goes away. The owner says the motor mount is shot, and that a shop told him that it only affects fifth gear because the motor is loaded down at the slower speeds.

I will be driving the car again this afternoon and plan to see if going faster in fifth will make it go away. It does not vibrate under any other conditions as far as I can tell so far.

Can someone help? Does this sound like a motor mount or something more serious?

Thanks,
Walter

Walt92Conv · 07-03-2002, 08:12 AM

Any ideas out there?

Thanks

RPM427 · 07-03-2002, 12:35 PM

It is prob the driveshaft.

Walt92Conv · 07-03-2002, 12:40 PM

Wouldn't a drive shaft vibration be evident in any gear or even under no power? The drive shaft speed is fixed with the speed of the rear wheels.

Thanks for the reply, I will definitely check it out.

explicitone · 07-03-2002, 01:07 PM

look at the mounts you can see them from up top. they may be cracked and rotted all the way through. my old mounts were shot when I bought the car and the way I could tell was when I reved the motor the motor moved a lot and if I left the line to hard the trans would more as well, to fix this I got the energy susp. motor and trans mounts from summit and they were 149$ for the set.and if its the driveshaft you can get the frpp alum. driveshaft for about 170$ from summit as well. and that takes about 10mins to throw in. ( four 12mm 12point bolts on the diff side and the driveshaft just slides out and slide the new one in and put the bolts back in and your done)

sn95gt19 · 07-03-2002, 04:32 PM

i had the same prob. in my car. twice, and about a month after it started i ended up blowing the tranny. could just be my luck but i doubt it. it could be something in the trans or i would say that the driveshaft is off by 1/2

phatpony · 07-04-2002, 11:31 AM

I had a similar problem and i just crawled under the car and disconnected the driveshaft and rotated it 180 degrees. It smothed out quite a bit. Be sure to use some thread locker on those bolts, they do back out all by themselves.

PKRWUD · 07-04-2002, 11:59 AM

Quote:

Originally posted by Walt92Conv
The drive shaft speed is fixed with the speed of the rear wheels.

That is exactly why it sounds like a driveshaft vibration. If it was an engine vibration, it would occur in every gear.

Take care,
-Chris

RPM427 · 07-04-2002, 01:54 PM

thats correct. Spend $220 to get your stock one balnced/straigtened with new u joints, or buy a brand new aluminum one for $190 from ford motorsports. If you get the FRFP driveshaft, your problems will probably go away.

Walt92Conv · 07-05-2002, 06:39 AM

Thanks for all the help, you guys are great.

07-03-2002, 07:08 AM	#1
Walt92Conv Registered Member Join Date: Jul 2002 Posts: 4	Vibration Need Help I am looking at buying a 92 GT convertible. In fifth gear there is a lot of vibration. If I shift back to fourth and maintain speed the vibration goes away. The owner says the motor mount is shot, and that a shop told him that it only affects fifth gear because the motor is loaded down at the slower speeds. I will be driving the car again this afternoon and plan to see if going faster in fifth will make it go away. It does not vibrate under any other conditions as far as I can tell so far. Can someone help? Does this sound like a motor mount or something more serious? Thanks, Walter

07-03-2002, 12:35 PM	#3
RPM427 Registered Member Join Date: Aug 2001 Location: Huntington NY Posts: 573	It is prob the driveshaft. __________________ -1993 Mustang, 900rwhp 03-04 cobra based 4v swap, full Griggs setup, project underway -1994 Ranger w/ 427cid windsor (daily beater) check it out!

07-03-2002, 01:07 PM	#5
explicitone Registered Member Join Date: Apr 2002 Location: racine ,wi Posts: 691	look at the mounts you can see them from up top. they may be cracked and rotted all the way through. my old mounts were shot when I bought the car and the way I could tell was when I reved the motor the motor moved a lot and if I left the line to hard the trans would more as well, to fix this I got the energy susp. motor and trans mounts from summit and they were 149$ for the set.and if its the driveshaft you can get the frpp alum. driveshaft for about 170$ from summit as well. and that takes about 10mins to throw in. ( four 12mm 12point bolts on the diff side and the driveshaft just slides out and slide the new one in and put the bolts back in and your done) __________________ RUN IT STAIGHT AND RUN IT HARD ________ Novi 2000 60' 1.46 1/4 10.67 mph 126.5 _________

07-03-2002, 04:32 PM	#6
sn95gt19 motors done......woohooo Join Date: Mar 2002 Posts: 799	i had the same prob. in my car. twice, and about a month after it started i ended up blowing the tranny. could just be my luck but i doubt it. it could be something in the trans or i would say that the driveshaft is off by 1/2 __________________ 95gt lazer red (98 cobra clone) Rice Haters Club Member #116

07-04-2002, 11:31 AM	#7
phatpony Registered Member Join Date: Apr 2002 Location: New Bern, NC Posts: 18	I had a similar problem and i just crawled under the car and disconnected the driveshaft and rotated it 180 degrees. It smothed out quite a bit. Be sure to use some thread locker on those bolts, they do back out all by themselves. __________________ '93 LX, Cobra intake, K&N conical filter, tremec, 4.10, billet quadrant and firewall adjuster, paxton fuel regulator, MAC equal length shorties, BBK X-pipe with cats, Flowmaster 2-chamber cat back with stainless tips No, I'm fat, the car is PHAT!

07-03-2002, 08:12 AM	#2
Walt92Conv Registered Member Join Date: Jul 2002 Posts: 4	Any ideas out there? Thanks

07-03-2002, 12:40 PM	#4
Walt92Conv Registered Member Join Date: Jul 2002 Posts: 4	Wouldn't a drive shaft vibration be evident in any gear or even under no power? The drive shaft speed is fixed with the speed of the rear wheels. Thanks for the reply, I will definitely check it out.

07-04-2002, 01:54 PM	#9
RPM427 Registered Member Join Date: Aug 2001 Location: Huntington NY Posts: 573	thats correct. Spend $220 to get your stock one balnced/straigtened with new u joints, or buy a brand new aluminum one for $190 from ford motorsports. If you get the FRFP driveshaft, your problems will probably go away. __________________ -1993 Mustang, 900rwhp 03-04 cobra based 4v swap, full Griggs setup, project underway -1994 Ranger w/ 427cid windsor (daily beater) check it out!

07-05-2002, 06:39 AM	#10
Walt92Conv Registered Member Join Date: Jul 2002 Posts: 4	Thanks for all the help, you guys are great.

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