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Please help with ongoing driveline vibration noise

"I checked again with the weight on the car. My yoke is exactly like yours, 2” from the seal flange to the big part of the yoke."
What is the distance from the end of the rubber boot seal to the yoke?
 
turbine68rt said:
"I checked again with the weight on the car. My yoke is exactly like yours, 2” from the seal flange to the big part of the yoke."
What is the distance from the end of the rubber boot seal to the yoke?
Click to expand...

About 13/16”. There is no way I could use a longer driveshaft, when removing the shaft, if I push it all the way forward till the output shaft bottoms out on the slip yoke plug I only have 1/2” clearance from the rear ujoint caps the the ears of the pinion yoke.
 
Here's a picture of trans shaft note how far it sticks out.
tb2.jpg
 


Fran Blacker said:
Here's a picture of trans shaft note how far it sticks out. View attachment 1033182
Click to expand...

Yes, as seen hear with the long seal boot. That leads me to another question, how much play should the output shaft bearing (the inner one that the C Clip under the mount holds) have? I know that slip yoke and bushing support the area that I’m wiggling but the inner bearing is also allowing the movement as seen in the video.
 
Don't know if wiggle is excessive? A whir sound could be tailshaft bearing, but don't know if it happens often. @dvw could answer, helped me out when I had trouble getting my VB back in trans. Told me have some turn rear tire while you put VB. I had forgotten that.
 
The output shaft can move quite a bit. The yoke riding in the bushing is what supports the outer end of the output shaft. Like I stated before “float” howl is almost always caused by the ring and pinion. Always around 40-45 mph as well.
Doug
 
As mentioned above, ring and pinion would be what I would check next. Specifically the contact pattern of the gear teeth. Do you have any pictures of the pattern from when the gears were set up?
 
Swapped in a totally different 741 case with 3.55's and the sound is still there at 40mph on the speedo even though the car is now moving faster at that 40mph speedo speed then it was before with the 3.91's. The transmission re-builder is doing a warranty swap for me once he test drove the car. He said he thinks its planetary noise for some reason. It gives me an excuse to swap in a new converter too... I was never happy with the one that's in it. I will report back within a few weeks with the result.
 
HotRod777 said:
Swapped in a totally different 741 case with 3.55's and the sound is still there at 40mph on the speedo even though the car is now moving faster at that 40mph speedo speed then it was before with the 3.91's. The transmission re-builder is doing a warranty swap for me once he test drove the car. He said he thinks its planetary noise for some reason. It gives me an excuse to swap in a new converter too... I was never happy with the one that's in it. I will report back within a few weeks with the result.
Click to expand...
I’ve only ever seen 2 planet bearing/axle failures in 35 years of Torqueflite repair. Both failures escalated very quickly from initial outset. They also filled the pan with lots of magnetic shrapnel.
Doug
 
dvw said:
I’ve only ever seen 2 planet bearing/axle failures in 35 years of Torqueflite repair. Both failures escalated very quickly from initial outset. They also filled the pan with lots of magnetic shrapnel.
Doug
Click to expand...

After explaining to the Transmission guy what I’ve tried, (short review):
-2 sets of axle bearings.
-3 different center sections with 3 different gear ratios, both clutch and cone type and 3 different sets of new bearings (1 koyo, 2 Timken). 2 different driveshafts, both balanced and new joints, new slip yoke, and 2 new tail bushings (standard and Teflon) the noise is still there and exactly the same.
He got in the car with me in the passenger seat, he drove up to 40mph and got the noise going... he pulled the shifter in 2nd and he varied the speed up to 60 and down to 20 multiple time and everything was silent. Shifted back to drive and noise instantly at 40mph.
He said, pull it and come to the shop Saturday morning with it, I’ll have another one build and ready to go for you.

I’m really hoping this does it... I’m $3k into chasing this issue.
 
dvw said:
I’ve only ever seen 2 planet bearing/axle failures in 35 years of Torqueflite repair. Both failures escalated very quickly from initial outset. They also filled the pan with lots of magnetic shrapnel.
Doug
Click to expand...
Doug, what do you make of this and is this the root of this noise I’ve been chasing for 1.5 years? This groove has worn .010 (measure with a mic) with only 1000 miles at most since the car was put together. The converter was from Pat Blias, (or at least whomever is selling off his remaining stock, it’s a factory 10.75” that has a warranty tag on it marked 4/2019. To rule out the basics:
-the crank bolts were still tight w/locktite.
-the converter bolts were still tight w/locktite.
-the flexplate was a stock 10” with the correct, small holes for 5/16” bolts.

I have another thread going in this section about what converter to replace this one with. This one would flash to avoid 2200. I’d like about 300-400 if possible.

BEF39E44-9AB5-4EBC-A156-2E68066E98C5.jpeg
 
Are the dowel pins in the block? There was no leak? Id like to see the pump bushing.
Doug
 
dvw said:
Are the dowel pins in the block? There was no leak? Id like to see the pump bushing.
Doug
Click to expand...
Dowels are in and all 6 bolts were tight.
No leak or even dampness on the front pump below the seal. I do not want to go digging into it being I am getting a warranty exchange. Does this hub ride a bushing not a bearing correct? If I look past the seal I see what looks like a bushing that is about 1/2” wide that has holes/dimples in it. Can’t see much beyond that.
Also, not sure if this is an issue, see the pic, after unbolted the converter easily slid back in almost a 1/4”. I know the bolts should always draw the converter to the plate a bit but is this too much? If the new tranny/converter/plate aligns like this should I put a washer between?

D14BAE18-8F6A-4826-8A42-1FAA3E67430A.jpeg
 
Yes the converter rides in a bushing behind the front pump seal. There are 2 types of bushing material. Bronze commonly used in production. And babbitt that is softer and more forgiving of converter wear. I always use babbitt. The converter should slide forward to the flex plate. The bolts should not draw the plate back to the converter. If this condition exists, the hub of the converter has interference into the bore in the rear of the crank. Roughly 3/16"-1/4" gap will work.
Doug
 
dvw said:
Yes the converter rides in a bushing behind the front pump seal. There are 2 types of bushing material. Bronze commonly used in production. And babbitt that is softer and more forgiving of converter wear. I always use babbitt. The converter should slide forward to the flex plate. The bolts should not draw the plate back to the converter. If this condition exists, the hub of the converter has interference into the bore in the rear of the crank. Roughly 3/16"-1/4" gap will work.
Doug
Click to expand...
Thanks for your continued replies.
I’m ok then, the converter easily slides in and then back out to the flex plate after it was unbolted from the flex plate.
One last question though as I try to cover all bases...
The stock 383 forged crank is 1965 and would have been used with a 19 spline converter. The front pump was updated to the 67+ and I’m using the 67 and up converter. They didn’t change the converter’s front nose register size when going from 19 to 24 spline on the big blocks did they?
(Like the slant and some 273’s did)
I’ll mic the crank and converter nose tomorrow morning, any idea what the clearance should be?
 
Last edited:
The converter snout diameter seems to vary a wide range from different sources. The cranks vary as well. As long as it fits the hole they work. Its when the converter wont slide into the crank that there is an issue. No, same spline count and outer diameter on the converter hub.
Doug
 
Well, I can finally post a wrap-up after 1.5 years and almost $4000 chasing the issue. It turned out to be the inertia ring on the driveshaft. The original driveshaft was spun balanced with new joints 2 different times at 2 different shops. Both said the shaft was "perfect". After 3 rings and pinions, 2 sure-grips, 2 cases, wheel bearings, 2 transmissions, 2 slip yokes and 3 torque converters I said "the shaft is the last original part".
For $150 the shop re-tubed it with a used non-inertia yoke out of their parts bin (reusing my rear yoke and slip yoke) and it's completely fixed.
 
Glad it is fixed. I doubt it was the ring, I bet the shaft had runout or slight indexing problems and they balanced it. We had a shop in town that was so good at building a straight shaft they did not need to be balanced, the guys we have now not so much, so I buy online. I never believed it but balance is a minor issue compared to indexing and running straight and true.
 
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