toyvet1

After replacing the engine,clutch, totally rebuild the rear end, full front suspenction, shocks,two sets of tires, rims, brake job. I have finally found the vibration that comes in at 80 mph. The transmission rear tail shaft bushing and front drive shaft yolk were shot. After having the trans rebuilt and being told by the rebuilder the scorn marks in the yolk would not hurt it . I got the vibration back in less than 250 miles, the rear bushing was trashed. Off came the tailshaft and installed a new rear bushing. Ordered a new yolk and 200 miles later no vibration!!!! :party: :party: :party:

Now all I have to do is bring down the water temp on the highway.....

joeveto

That's weird. Hot Rod just did a think on this in their tech section. One of the first things they suggested, was the tail shaft bushing.

Glad you found it. Sorry it took so long... :(

As far as the temp goes, there is another post on it. I suggest starting with bleeding the system. And then replace the radiator seals.

:cheers:

OkeeGuy

i get that same vibration at that same speed and could never figure out what it was...
im pretty sure that my yoke is fine, had my drive shaft balanced too...
how hard of a job is it to replace that bushing?
skip the trany removal stuff...i know ALL ABOUT THAT! :rolleyes:

MotorHead

That's great,when I had a vibration that's the first thing I fixed turned out to be the rear wheel bearings :lol:

The guy I took it to replaced the bushing without removing the tranny or tailshaft


[Modified by MotorHead, 9:28 PM 9/17/2003]

SharkPilot

Replacing the trans rear bushing and drive yoke fixed my vibration too.
There was a fairly serious vibration that started at about 80 and by 100 it was getting scary. The shifter would rattle back and forth.
I rebuilt the trans earlier this year and found severe wear on the yoke and bushing. I replaced both and the vibration was gone. :yesnod:
So far I have only gotten it to a bit over 90, but it was very nice.
I still have a small amount of "thrumming" at about 65 on a smooth road, but I am going to try and rotate the drive shaft 180 degrees at the differential yoke. That may be the problem. I just haven't had a chance to do it yet.
Too busy driving it. :steering:
Enjoy that Vette! :hurray:

toyvet1

Oh I forgot drive shaft and half shaft balanced twice.
As to replacing the bushing, drop the trans, remove the speedo drive. remove the drift pin out of the reverse shaft. Unbolt the five bolts to remove the tail shaft. Pull back on the tail shaft about a inch and full out on the reverse shaft. Look inside the trans when you pull out the reverse shaft and watch how the dog attatchs to the reverse gear. Slowly remove the tail housing and watch the reverse counter gear as you pull it apart so you see the order it has to got back together in.
I got the bushing from GM. it is a inch wide . the bushing that came out was only five eighths of a inch. The new GM piece give much more contact area. I used a 36mm Hushy socket from Home depot to drive out and install the bushings. :steering:

DMONSVETTE

:cheers: :thumbs: :seeya

OkeeGuy

it sounds as tho you did this under the car without removing the trany...
is that the case?
also...do you know the GM part number?
is there anything else i will need like gaskets etc?


[Modified by SIGNGUY, 8:41 AM 9/18/2003]

toyvet1

I removed the trans to replace the bushing. The parts numbers

Bushing 3978765
Rear gasket 3787720
Rear seal 6260707

burners

SIGNGUY, that wont work for you. With a 4 spd you will have to pull the transmission in order to remove the tailhousing and you wil need a midplate to tailhousing gasket. Check out http://www.texracing.com/ they can sell you all the parts needed. They had the best price I could find for a new yoke and they have wider bushings for racing so they will last longer.