bigmal

I got the repaired tailshaft back and went to fit it. The new yoke is longer than the old yoke so it wouldn't fit. I took it back to them yesterday to have it shortened 3/4". Starting to lose confidence with this company. Next will be the argument of paying for all of this. Fingers crossed the vibration is gone at the end.

About 1:15 away. We will probably run into each other at some point.

Update: I took the drive shaft back to the company that made it and they found a thrust washer missing from inside the rear uni cap. This will make the uni offset about 1mm. I saw a washer on the floor of the garage and didn't recognise it so added to the washer box. This explains why the vibration got worse after changing the transmission bushing. Extremely happytto find that. They have put the shaft on their balancer and said it is slightly out of true. They are repairing it today and I am getting a new yoke and two new uni's just to be sure. I'll report back as soon as I have driven it again. Fingers crossed!!!

Hi mate, that build looks great. Where abouts in Sydney are you? I'm in Woronora Heights.

I would be concerned running it without the drive shaft yoke in place. While I like the idea I don't know enough about any damage it could cause or fluid loss. Thanks

Thanks Bob, will give it a go

Hi mate, all mounts have been replaced. No noticeable difference

Hi mate, thanks for the response The driveshaft is custom made by Hardy Spicer with new universals. The previous shaft was a replacement and turned out to be bent and out of balance. Changing made no differnce. As far as I know the diff is in good condition. No noises and traction lock function well. Rear brakes are drum. I haven't run with the wheels off yet but will try that on the weekend. For some reason removing and replacing the drive shaft has made it worse. I did remove the cross member and rear shock mount to remove the FMX extension housing but there is only one way to replace it. I will check that the pinion angles are still matched.

Hi mate, yes a new tailshaft/driveshaft. I had the same problem with the previous driveshaft which is why I've replaced it with new good quality uni's. I must be close because what ever I did has affected the vibration (worse). Actually to the point where I am afraid to sit at that speed for fear of throwing the driveshaft. As I have disturbed the rear shock mount I will check the pinion angles again just to make sure nothing has changed. Juts need to be away from it for a few days.

Well, an update. I had a new bushing fitted to the rear of the transmission, as suggested. There was a little play, and I was happy to eliminate this. Not only did it not fix it, it's now worse. This is doing my head in. It's not an issue with how I mounted the rear uni, as I triple checked it. I have to be close, as it's something I've disturbed. Both uni's are new and fitted by a reputable company. I'm thinking of taking the tail shaft back and getting them to check the balance and uni's.

When I replaced the flex plate that I had damaged I told the engine shop bloke that I had replaced it. He said If I bring the old and new flex plates he can balance against the old. I had already thrown it out. Still kicking myself.

I've just jacked the car and confirmed that there is up and down play in the yoke going into the rear of the transmision. On the weekend I will get the rear out and have the bushing replaced. I'll report back once I have an outcome. Thanks for all your help

You are getting a little out of my area of knowledge here. The internals were supplied including harmonic balancer and flex plate. Pistons and rod were balanced separately. I understand the crank was balanced with the flex plate and harmonic balancer in place. The old flex plate had some metal remover during the process. Not a lot.

Both the flex plate and harmonic balancer are new. When I told the company that internally balanced my engine that I had then replaced the flex plate afterwards, they said it should be balanced again. The engine vibration is not that significant, but something I would like to tackle at some point. Thanks.

Sounds great. I will replace it regardless so at least its eliminated. I just need to source a bush.

I'll be checking that first thing on the weekend. As I'm not a transmission man, just confirming I need to drain the oil, remove the housing, and a press to change the bushing? Assuming its worn.

Don't be sorry. I'm really glad to have the input. The angles are parallel. Car on stands, digital protractor set to zero on the pulley and taken to the diff is also zero. As I haven't checked the car is level, I can't say what the true angles are, just that they both match.

No, that's something I haven't checked. The yoke appears to be in good nick and I've replaced the seal so there are no leaks, but I haven't checked for a worn bushing. That is new territory for me. Is it easily replaced? I'm getting a little excited....

Hi mate, I am using a digital protractor and I set zero on the front pulley. Then when I take it to the rear pinion it is also zero. Makes it a little simpler then using maths :) Yes, using wedge shims. I have 4 sizes 1, 2, 3 and 4 deg. I didn't know what tolerance was acceptable so used trial and error.

Thinking of you mate. We've got similar issues down hear. Its no fun but can't last forever.

Mine too

Hi mate, that's some very helpful information. I have tried shimming the pinion up and down 1, 2, 3 and 4 degrees. 3 deg up has the least vibration and a 0 degrees difference between the diff and transmission angle. The amount of pitch up with the engine under load is something I was wondering about. As I have shifted to neutral at the speed where the vibration is at its worst, the diff is not under load and the vibration is unchanged at that speed. It also shows that as the engine has dropped to idle, the major vibration is somewhere rear of the torque converter. What troubles me most is that I may have eliminated parts as the cause by replacing them and the new parts may still be an issue. First replacement tailshaft was bodgy, so a new one fitted. I thought I'd found the culprit, but no noticeable difference.

Hi mate, by 0 deg I meant that the difference between the diff angle and the engine front pully is 0. The Pinion angles are adjusted with 3deg shims so there is 0 deg split. I tried shims at 1, 2, 3 and 4 up and down. 3deg up has reduced the vibration to the best yet but still there.

Standard 18oz external, but the internals were balanced on a machine while stripped. As I have replaced the flex plate since then, so I may be looking at another strip. While laying awake in the middle of the night I've been trying to come up with a way to balance the flex plate in situ. I was thinking of placing small tire weights on the plate and repositioning them by trial and error. Unfortunately there is not enough room through the bottom plate. Another thought was to remove the transmission and attach the bell housing and use the same method. If I can get rid of the vibration with this method I could then drill holes opposite. Anyone tried this? Or am I off the mark? Or just bite the bullet with another strip and balance? Noting that the major vibration is not the engine, its somewhere rear of the torque converter.

Thanks for the updates. As I asked the question I had a horrible feeling I wouldn't like the answer. Happy he's just busy. Now just to entice him back!