5sp tranny is howling

Engine, Transmission and related drivetrain.
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MikeY
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5sp tranny is howling

Postby MikeY » 15 Oct 2016 10:58

I'm trying to troubleshoot the fresh restoration. I installed a unknown zx 5sp. I very loud howl seemed to come from it. New clutch and throwout bearing. Weird part is it goes away on a sharp left hand corner and gets a bit worse on rights. Sure doesn't seem like a wheel bearing. So installed a second unknown 5sp. Same thing. You can feel the growl with your hand on the tunnel. I did notice that when installing the drive shaft it was a tight fit. Barely enough room to get it in place. Is there a chance that might be causing the noise. I'm getting too old to re and re transmissions on my back. Ive used Pennzoil 80/90 oil in both. Other than shortening the shaft I'm down to installing a 4sp. It's a bit frustrating when the car is so close to finished.

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defdes
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Re: 5sp tranny is howling

Postby defdes » 15 Oct 2016 12:36

I feel like there was a very similar post to this in the last 6 months, perhaps someone less addled can remember.

datzenmike
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Re: 5sp tranny is howling

Postby datzenmike » 15 Oct 2016 13:03

Check the exhaust pipe is clear of the body by pulling on it. Can you get it to touch anything?.

Do you have poly engine/trans/differential mounts anywhere? If rubber, are they in good shape and engine well supported. You may need a length of 2x4 to pry hard enough to move the engine if at all.

Swap left with right side tires. Problem swap also? eliminates tires.

Swap hubs side to side. Problem swap also? eliminates bearings or poor preload setting.

.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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MikeY
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Re: 5sp tranny is howling

Postby MikeY » 15 Oct 2016 14:17

I found Steve in Edmonton s thread and started to look for tranny to body contact. I was using what looks like a 240 tranny mount with David Carroll s xmember. One of the nuts on the bolt holding the mount to the tranny is making contact with the x member. Maybe the rubber has collapsed a bit. I will try to order a new one. I have dug up another crusty one and will try that. I will post results. The hole was tight but looks OK. And I'm still worried about how tight the drive shaft was to install. When moved forward towards the tranny as far as it will go there was about 1/4 of an inch to draw it back to mate to the diff. Seems a bit tight but in theory there is little movement here. Right??

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SteveEdmonton
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Re: 5sp tranny is howling

Postby SteveEdmonton » 15 Oct 2016 16:15

Hey, thanks for posting that last bit, Mike-- about the tranny-mount bolt (nut) touching the tranny X-member. I'm not sure I looked at that as a possible source of my own problem.

And yes I'm still having noise when going straight, getting worse when I turn one direction, and going away when I turn the other. I've eliminated 3 or 4 other sources of unwanted vibration / banging / rubbing, while searching for this one, but whatever is causing it is turning out to be VERY hard to find! Maybe your discovery will turn out to be my solution too....
'71 4-door
'74 MGB-GT
'04 Miata

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MikeY
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Re: 5sp tranny is howling

Postby MikeY » 20 Oct 2016 10:22

Thought I would update the group. I replaced the tranny mount with another one I had laying around. And it gave me the clearance between the mount nut and David's xmember. And the noise is gone. It was hard to imagine that the howling was normal tranny sounds. Thanks to the list for pointing me in the right direction. Now onto fuel starvation and exhaust pipe rattling in xmember.

Three B's Racing
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Re: 5sp tranny is howling

Postby Three B's Racing » 21 Oct 2016 05:13

I'd be concerned about that tight fitting drive shaft. Though the shaft doesn't move in or out like straight axle drive shafts because of the rearends up and down movement, there's a reason Nissan designed clearance in the 510 drive shaft. Glad you found the issue win win!!
"Lastnight the wife said oh boy when your dead you can't take nothing with you but your soul oh "Think"
- John Lennon

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SteveEdmonton
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Re: 5sp tranny is howling

Postby SteveEdmonton » 22 Oct 2016 18:06

MikeY wrote:I found Steve in Edmonton s thread and started to look for tranny to body contact. I was using what looks like a 240 tranny mount with David Carroll s xmember. One of the nuts on the bolt holding the mount to the tranny is making contact with the x member. Maybe the rubber has collapsed a bit. I will try to order a new one. I have dug up another crusty one and will try that. I will post results. The hole was tight but looks OK. And I'm still worried about how tight the drive shaft was to install. When moved forward towards the tranny as far as it will go there was about 1/4 of an inch to draw it back to mate to the diff. Seems a bit tight but in theory there is little movement here. Right??


I finally got time today to check the clearance on my car between these bolts (tranny-mount-to-tranny) and the tranny crossmember, and sure enough just as Mikey found, there was very little space. So I pulled the crossmember, then the tranny mount, and created more space by: (1) using different bolts that have smaller heads, and (2) moving the lock-washers from the bottom to the top. A short spin around the block suggests that several types of vibration noise in my car, too, are pretty much GONE!!!!

After checking umpteen other possible sources for this noise, this was both humbling and rewarding. (How come I never noticed this before? Oh well-- it's fixed!)

The fit of Dave Carroll's cross-member is great in every other way. I guess you just have to really check this detail carefully, to make it perfect.
'71 4-door
'74 MGB-GT
'04 Miata


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