3rd gear knock updated 5/28

[Kevin - Illinois]

Well the rebuilder had me pull the rear end and transmission and bring him the transmission that he rebuilt. He found .050 end play on both shafts in the front and rear. He fixed it and I got it in today.
The knock is still there in 3rd gear only just like it was to start with. No difference. I have $4,000 into this between the rebuilt long block and rebuilt transmission, not counting gas and time, grease, gaskets, etc... I asked him to come and listen to it, even offered to give him $100 for gas for the 90 mile drive from Skokie. Sure wish he would have done that. Well I won't make Sharon now.

I added a video of the knock...

https://www.youtube.com/watch?v=VMb7d...ature=youtu.be

[TinCup]

Kevin,
At this point I would enlist someone who could ride along with you and video the symptons. Almost any phone today can do this and you could send it to the builder. Then there is no better way to communicate your point.

[Kevin - Illinois]

Video of the knock...

https://www.youtube.com/watch?v=VMb7d...ature=youtu.be



Kevin

[Benson]

Kevin,

There is a steel spacer plate with 4 holes that goes under the heads of the 4 bolts that hold the flywheel to the crankshaft ... is this plate installed?

If not the flywheel bolts (or wrong length bolts are used), the bolts will strike the rear main bearing area of the block or bearing cap.

[bogdonj]

yeah what BENSON said... almost sounds like flywheel bolts are just touching but why would it only be in third and not all gears?

[Benson]

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Kevin,

Can you put rear axles on two sturdy jackstands (4 lagged ones are sturdier) and run the video? That will eliminate the road and wind noises. Block front wheels.

You may know this but cinder blocks or bricks can crumble under the vibrations!

This was true of cinderblocks 45 years ago ... maybe they are better built today!!!

I would not leave the driver position with wheels spinning and maybe park car pointing away from the garage in case if falls off the stands. Try to keep speed down to 20 or 25 if you can reproduce the noise that slow.

[Benson]

Originally Posted by bogdonj

yeah what BENSON said... almost sounds like flywheel bolts are just touching but why would it only be in third and not all gears?

Yes I can not see a reason for 3rd only either...

[Bob C]

This is a real long shot but could the cluster gear be shimmed to far to the rear letting
the 2nd-3rd sliding gear teeth hit the cluster gear teeth in high gear?

Bob

[Kevin - Illinois]

The knock seems to be coming from the motor side of the flywheel or back of the motor. I will try lifting the rear end and taking another video tomorrow...

[TinCup]

Love that video! When you pulled the transmission did you see anything around the flywheel that looked like it was rubbing? There is definately something there.

[Tom Wesenberg]

Can you feel the clicking in the gear shift lever?

Have the passenger probe around with a stethoscope while you drive and make the noise.

[columbiA]

A friend had a similar noise only in high gear.The 2nd-3rd shifter fork was slightly bent & moved the 3rd sliding gear to touch the edge of the front gear on cluster.He replaced the shift tower & it was fine.

[Kevin - Illinois]

I didn't see anything that appeared to be hitting the flywheel, nor did I see anything loose. I checked and the pilot bearing was in place and as far as I could tell it looked fine.

Tom, I can barely detect a click or knock in the shifter. I'm having a tough time finding a passenger to do the stethoscope but that does appear to be next.

The first thing we tried was to replace the shifting tower but it didn't help.

[Kevin - Illinois]

I also checked the U-joint and found no problems. Then I promptly greased it up the Tom Wesenberg way

Thanks Tom, that saved me a hundred pumps!

[Farrell In Vancouver]

Kevin. May not be of any help but I am curious. How much free play have you at the throw-out bearing? In the video it looks like it's riding on the pressure plate and not moving back once engaged? The return spring looks like it may be stretched? For now I'll go along with colmbiA as it sound like trans. teeth rattling together. Can you borrow another tower and see if that eliminates it?

[gweilbaker]

Does it have new gears? I had one that had a deformed fork grove, where the manufacturer stamped their name, it made a noise but not quit like you video.

Does it the noise change if you pull or push the shifter?

[H. L. Chauvin]

Kevin,

This is offered only with sincere respect for your dilemain trying to locate the exact "SOURCE" of the noise:

Maybe shift gears & quit thinking like a mechanic & begin thinking more like a detective.

Smoke means fire, bread smell means bread baking -- from what I hear on the your video, it appears to be more of a 3rd gear knocking/grinding noise than just a knocking, like one metallic material rubbing on another.

If a partial metal grinding noise is the case, steel on steel, this grindng will produce minute metal filings which possibly could only be detected with a magnet on surfaces not in oil, or possibly metal filings in mixed with oil.

If metal particles are in the transmission's 600W or the engine's 30 weight , appears a sample could easily be drawn from both drain plugs after the engine is at rest for 24 hours, then pass the magnet through the oil sample then gently in paint thinner to dilute the oil & next observe the magnet with a magnifying glass.

Far shot in the dark, but just trying to help find the source of this noise.

Car on stand with less road noise, as suggested above, would also help detective work.

[James Rogers]

Sounds like the throw out bearing to me. The tranny sure has a bad whine for a new rebuild.

[Kevin - Illinois]

I agree James on the whine...however the rebuilder says it's normal since the transmission doesn't have angle gears. We did look at the throwout bearing and it looked fine.

I did notice very light scuffing on the transmission side of the flyweel teeth. As though the starter gear is not a perfect fit. However the starter is engaging and disengaging correctly, doesn't grind or anything. I blew this off since I figured that if there was a problem with it I would hear it in the starter and even at an idle.

[Brentwood Bob]

Is the starter ring seated onto the flywheel, or can you find a gap with a feeler gage/screwdriver? The ring gear can walk off the flywheel. Bob