[HALFWAY]

I have the drive shaft out and the u joints feel smooth through their travel no sticking, no clicking although one is slightly tighter, the front u joint, particularly the pair for the yoke that slides into the tranny.

I still need check the trans bearing but need to know what to look for or how to check. I am going back under the car and see what I can.

While the shaft is out I am going add more grease, try to make they lubed well. Probably do the 180* install just to see. Most likely have a new set installed for peace of mind.

[Tom Vaught]

Remove the driveshaft (after you push up and down and sideways on driveshaft when installed in the tailstock of the trans).

Now remove the driveshaft (on the rear axle) and AGAIN push up and down and sideways on driveshaft yoke when installed in the tailstock of the trans). and see how much movement you have there at the rear tailstock trans bearing.

I had two failures, over the years, on that tailstock bushing. It was due to me abusing the driveline severely with enough force to destroy several 8.2 rear axles.

Tom Vaught

[HALFWAY]

Originally Posted by Tom Vaught

Remove the driveshaft (after you push up and down and sideways on driveshaft when installed in the tailstock of the trans).

Now remove the driveshaft (on the rear axle) and AGAIN push up and down and sideways on driveshaft yoke when installed in the tailstock of the trans). and see how much movement you have there at the rear tailstock trans bearing.

I had two failures, over the years, on that tailstock bushing. It was due to me abusing the driveline severely with enough force to destroy several 8.2 rear axles.

Tom Vaught

Yes I tried moving the driveshaft front to back, side to side trying to find anything and I couldn't perceive any noticable movement.

The shaft is still out, so I can insert the front yoke and check for any play.

The car has been in the family since new so intentional abuse is not likely, age on the other hand.

[Tom Vaught]

Please do that test. Rear of driveshaft on the floor, Yoke in the transmission, how much
play in the side to side and up and down directions in the yoke vs bushing.

Tom V.

[HALFWAY]

First thing in the morning, will report back.

[HALFWAY]

Originally Posted by HALFWAY

First thing in the morning, will report back.

I am retired so plenty of time, also means I am older and crawling around under the car like an inch worm is hard on the body.

[dataway]

0.010" is fine for the run out, better is better. Can't find it now, but when I came across specs for runout I think the limit was 0.015"

By the way .... I've got the original trans yoke, driveshaft and rear end in my car ... any way to spot the original orientation? Did the factory just use a mark, or did the peen something? I'm sure mine has gotten mixed up after being apart for decades.

[HALFWAY]

I got back under the car this morning and inserted the yoke back into the trans mission. I grabbed the shaft of the transmission and tried to move it up, down, side to side. If there is any play I can't see or feel it. With the yoke inserted there is very little if any play.

Taking the driveshaft in to get new u joints. Hopefully this will take care of the vibration.

[OG68]

Originally Posted by dataway

By the way .... I've got the original trans yoke, driveshaft and rear end in my car ... any way to spot the original orientation? Did the factory just use a mark, or did the peen something? I'm sure mine has gotten mixed up after being apart for decades.

I don't recall seeing any mark on mine, but the 68 service manual instructs you to mark the driveshaft and companion flange when disassembling. (Driveshaft Chapter)

[dataway]

Originally Posted by OG68

I don't recall seeing any mark on mine, but the 68 service manual instructs you to mark the driveshaft and companion flange when disassembling. (Driveshaft Chapter)

That ship sailed about about 30 years ago

Well, I got a 50/50 chance it's right.

[67Fbird]

also if you are using greasable joints...make sure they put the zerk in the right place....lol
power should squeeze the zerk....not try to tear it "open" wouldn't want to badmouth a u-joint due to improper install.

[dataway]

Well there is something I've never thought of before, and I've seen photos of where they have failed at the zerc.

[OG68]

Although I've never had any problems with the zerc fittings, it's my understanding the joints without the fittings are stronger.

[geeteeohguy]

Originally Posted by Tom Vaught

Check your yoke to tailstock bearing at the far rear of the manual transmission.
Tom V.

This^^^. I had the same issue with my 4 speed '65 and the tailshaft bushing was worn out as well as the front driveshaft yoke, which was worn to a saddle where it rode on the bushing. A new yoke and bushing eliminated all vibration. The bushing can be removed in-car with a TH350 rear bushing puller tool quite easily.

[1968GTO421]

My brother is doing a TH350 rebuild so I decided to find this rear bushing puller tool for him. It's KD Tools #3127. After searching for over an hour I could not locate one, including calling AutoZone to see if they loan it out (nope). There are probably better ways, but I'm going to tell him to just take the rear trans housing to a tranny shop and have them do the bushing replacement.

[HALFWAY]

Well the new u joints helped a little but it looks like I will be trying to find someone to replace the rear bushing and seal if needed.

One step before that is get tires checked to make sure there is no balance issues.

[abefromen]

Originally Posted by HALFWAY

Well the new u joints helped a little but it looks like I will be trying to find someone to replace the rear bushing and seal if needed.

One step before that is get tires checked to make sure there is no balance issues.

Was the shaft balanced before and was it re-balanced after new joints were installed?

[HALFWAY]

It was balanced before and I asked that it be checked again. I don't see any changes to the balance washers though.

I described my issue with the mechanic he also was leaning towards a bad bushing in the end of the transmission.

I have a call into the GUY in town that is the manual transmission expert.

I am hoping the bushing can be replaced while the transmission is still in the car. Maybe just the back end of the transmission, which I might be able to do but I can only get the car a foot or so off the ground. Anyway I will wait for his call.

[462gto]

There are videos on YouTube showing how to replace the bushing on the car.

Also on ebay there are tools available for doing this. Try searching on ebay Zamco Z-0160 I think this may be the tool you need. You could check with Zamco 210-924-2320 to be sure.

I haven't done this job or used any of Zamco tools but I'm getting ready to and this is what I've found in my research.

I also found the seal and bushing kit at O-reilly.

[NeighborsComplaint]

The drive shaft is still turning when the car is in neutral so that proves othing. It's a good test for a throw-out bearing noise but that's about all. Could be tail shaft bushing, could be pinion bearing, could be drive shaft out of phase from a twist. A balance issue is usually more pronounced within a given speed range. It starts off unnoticeable, comes out of nowhere and then goes away at higher speed. It is usually accompanied by a buzz in the rear package tray in response to the vibration.