LS1GTO Forums banner
21 - 34 of 34 Posts

·
Registered
Joined
·
462 Posts
Maybe I missed it but everything you're describing sounds like the tailshaft bushing in the back of your trans is dead. While I haven't had an issue in my GTO, I had issues with the T56 in my El Camino and ended up pulling the tailhousing off with the trans in the car still to put in a new bushing. That yoke looks awful.
Technically the bushing isn't an available replacement item but some shops like Texas Drivetrain Performance sell their own version of one.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #22 ·
Maybe I missed it but everything you're describing sounds like the tailshaft bushing in the back of your trans is dead. While I haven't had an issue in my GTO, I had issues with the T56 in my El Camino and ended up pulling the tailhousing off with the trans in the car still to put in a new bushing. That yoke looks awful.
Technically the bushing isn't an available replacement item but some shops like Texas Drivetrain Performance sell their own version of one.
I am almost certain the bushing is shot. I too looked at the bushing Tex Dr Per. sells. I stopped in to see my drive line guy today and showed him the pics of the yoke. He stated immediately that the tailshaft bushing was shot, and that the yoke needs replacement. My response was that I would clean the yoke with emery cloth. He said you can but the bearing will spauld again and build up on the yoke once more if you don't change it.

I'm pulling the tailshaft and will drop it and the DS off with them tomorrow.
 

·
Registered
Joined
·
137 Posts
I've got a vib from 65-75 I've been trying to track down.. I've done a ton of bushings so far energy diff insert, pedders rear subframe bushings, full poly on front control arms and radius rod with a huge tightening after the subframe bushings.. just ordered rear control and trans mount in poly but did find a crack in the trans crossmember so gotta replace that with the trans mount. I'm wondering if I need to add a washer like above to see if that'll help or if I need to rotate the dss to help. Still chasing my tail on that


Sent from my Pixel 4 using Tapatalk
 

·
Registered
Joined
·
462 Posts
I am almost certain the bushing is shot. I too looked at the bushing Tex Dr Per. sells. I stopped in to see my drive line guy today and showed him the pics of the yoke. He stated immediately that the tailshaft bushing was shot, and that the yoke needs replacement. My response was that I would clean the yoke with emery cloth. He said you can but the bearing will spauld again and build up on the yoke once more if you don't change it.

I'm pulling the tailshaft and will drop it and the DS off with them tomorrow.
Yeah I would swap the yoke at that point too, they aren't all that expensive and definitely worth it if you know a decent driveline guy.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #25 ·
Here is a pic. If you look at the bushing, there is no brass left and only the shell. That explains the silver gray marks on the yoke. Obviously, from the bushing shell. Two. I put the yoke in the tailshaft to check the clearance after it was apart. It flopped around so badly I started to to laugh.

I took it to the shop. Pressing in a bushing is of little concern and routine for them. I asked about the yoke? He said we'll try to polish it, but if not, then they'll replace it. He also said he's seen alot worse, where the yoke wore through the bushing and cut into the case. The upshot being the case is OK. I should get it back on Monday or Tues.

The aft rear bearings and gears look great. No visible wear, I will put it back together with the new bushing and I'm almost certain this is the main vibration cause.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #27 ·
I've got a vib from 65-75 I've been trying to track down.. I've done a ton of bushings so far energy diff insert, pedders rear subframe bushings, full poly on front control arms and radius rod with a huge tightening after the subframe bushings.. just ordered rear control and trans mount in poly but did find a crack in the trans crossmember so gotta replace that with the trans mount. I'm wondering if I need to add a washer like above to see if that'll help or if I need to rotate the dss to help. Still chasing my tail on that


Sent from my Pixel 4 using Tapatalk
At that speed 65 there is a common vib to many GTOs. Check the front wheel balance and retorque the wheels to 100 ft lbs. BTW, you'll have to point out the crack, sorry I don't see it.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #32 ·
I've got a vib from 65-75 I've been trying to track down.. I've done a ton of bushings so far energy diff insert, pedders rear subframe bushings, full poly on front control arms and radius rod with a huge tightening after the subframe bushings.. just ordered rear control and trans mount in poly but did find a crack in the trans crossmember so gotta replace that with the trans mount. I'm wondering if I need to add a washer like above to see if that'll help or if I need to rotate the dss to help. Still chasing my tail on that


Sent from my Pixel 4 using Tapatalk
I want to follow up with you again. The reason I think it isn't in the bushing, or the vib isn't in the xmember or trans, is because you stated the vib occurs at 65-75. My vib starts at about 40 and gets worse as you speed up. The crack should be fixed, but I would think if it was the vibration scource it would vibrate at many speeds. Just a thought. Good Luck and let us know what you find.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #33 ·
I got the DS and the tailshaft back today. I think I will have time over the weekend to install them. They balanced the shaft for the new yoke, and I spoke with the owner about tweaking the drive line and setting the right angle. Got a lot of good tips.

He knew the car came with a two piece. I asked if using a one piece was causing vibs and a worn out tail shaft bushing. He said hell no! The two piece is there to cover manufacturing sloppiness and/or loose tolerances. He said a one piece set up right is the best way to go.

Will update after install.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #34 · (Edited)
Ok, got it all back together and the wiped out tail shaft bearing and worn out DS yoke were the problem. I set all the angles as mentioned by the DS people. I set the trans 3* down angle and the diff at 3* up angle. Those are the correct angles. I have pics of the angle finder setting both angles and will post them later.

I know, I know many here believe the angles should be set at 1-2* up and 1-2* down. But, I set them at the angle recommended by the shop for a one piece shaft. I'm going to drive it for a few hundred miles to see how this set up works out. This shop BTW also does monster truck drives as well as off road equipment drives and cars. I have faith in them, but will experiment if needed to find the right set up angle for our cars.

As yet, I had it up to 100 without vibs (OH YEA), but not more. Waiting for a trip to the track or Mexico to test 125. :cool:
 
21 - 34 of 34 Posts
Top