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Trans problemconfused smiley. Help needed
Posted by: bruces ()
Date: October 04, 2018 11:13PM

The trans is the original 1968 4sp with apx 57k miles. The diff is a fresh rebuilt 3.55 posi using Metcalf's 4 spider gear conversion.
This unit is mated to my 3.0L EFI Turbo. Just hit 1000kms. Still working out bugs/tuning it.
The problem: Noticed a strange Humming/not quite grinding sound coming from the back, but only when under load. It was fairly quiet at first, and very infrequent. As it became louder and more frequent, it started to grind when shifting into 3rd. I adjusted the clutch cable, but that didn't help.
Now the noise is very loud and continuous while under load. It worsened this afternoon to the point where it felt like a dragging feeling while accelerating, and a strange loud creaking throughout the car when turning while coasting. Got underneath it and found of oil under the diff. Checked all of the bolts holding the transaxle together, as well as the finned Aluminum Diff cover. Everything was tight. Checked the fluid level, but it was fine also.
Is it possible that the Trans has stretched??? I have done a number of hard launch burnouts this summer....

Any thoughts would be greatly appreciated.

Bruce S
'68 Monza Coupe
140 Turbo EFI
White Rock, BC

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Re: Trans problemconfused smiley. Help needed
Posted by: Mel ()
Date: October 05, 2018 05:43AM

She's toast sad smiley

Orangeville, Ontario. CANADA

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Re: Trans problemconfused smiley. Help needed
Posted by: vairmech ()
Date: October 05, 2018 05:50AM

That could be in the diff! The rear pinion bearing takes a beating. Specifically the pinion shim actually seems to go away. What one person had to do was put the shim under the cup in the diff!

No matter what it needs to come apart and everything looked at.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Trans problemconfused smiley. Help needed
Posted by: BobV66Vair ()
Date: October 05, 2018 05:56AM

I had one years ago that sounded like that. I ignored it and whole thing locked up while driving it on a date. Had to have it picked up and towed. Plus a large bill to rebuild the diff again. That sound is a bad thintg. stop driving and pull the trans/diff. I think your rebuilder may owe you a free rebuild.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Trans problemconfused smiley. Help needed
Posted by: Mel ()
Date: October 05, 2018 06:12AM

After you fix it smiling smiley….STOP ABUSEING IT !

Orangeville, Ontario. CANADA

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Re: Trans problemconfused smiley. Help needed
Posted by: vairmech ()
Date: October 05, 2018 06:25AM

BobV66Vair Wrote:
-------------------------------------------------------
> I had one years ago that sounded like that. I
> ignored it and whole thing locked up while driving
> it on a date. Had to have it picked up and towed.
> Plus a large bill to rebuild the diff again. That
> sound is a bad thintg. stop driving and pull the
> trans/diff. I think your rebuilder may owe you a
> free rebuild.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Ummmm, NOPE! The initial post makes any warranty go away.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Trans problemconfused smiley. Help needed
Posted by: v8vair ()
Date: October 05, 2018 08:19AM

Hard Launches and Burnouts !!!! Could be a bad rear wheel bearing ?
Mike

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Re: Trans problemconfused smiley. Help needed
Posted by: davemotohead ()
Date: October 05, 2018 08:30AM

I have 3 busted diffs under the bench from doing hard launch burn outs smoking smiley





Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)

-----------------------------------
Rust Free Lancaster Ca

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Re: Trans problemconfused smiley. Help needed
Posted by: 66vairman ()
Date: October 05, 2018 09:14AM

Stop driving the car, pull the transaxle before you break the case.

One thing to check!! You have a 68 4 speed. The differential pinion gear shaft MUST be a 66-69 style. If a longer 65 style pinion gear shaft was installed that will result in problems. Article was published in CORSA magazine and online here some time back.

When I was a "kid" I used to do burnouts, rev the engine way up with the clutch depressed (great for the throw out bearing - LOL). Then I learned how things work while doing my own repairs. I STOPPED abusing my cars after that.

Then again I know a guy who does burnouts with his Corvair and it does break and he says "For me that's the price of having".

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Re: Trans problemconfused smiley. Help needed
Posted by: bruces ()
Date: October 06, 2018 01:46PM

Thanks for the input guys. When I get a bit of time I'll pull it apart. I just have a hard time believing that a new 4 spider gear diff couldn't handle a dozen launches over a few months. I would light em up all the time on the stock diff. What's the point of building it up if you can't beat on it a bit.
Feeling very frustrated. Maybe I shoulda gone V8 with an LS and G50....

Bruce S
'68 Monza Coupe
140 Turbo EFI
White Rock, BC

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Re: Trans problemconfused smiley. Help needed
Posted by: 66vairman ()
Date: October 06, 2018 02:05PM

Don't forget to verify the pinion gear shaft length if it was replaced.

If you can't find the article them PM me.

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Re: Trans problemconfused smiley. Help needed
Posted by: REM654DPG ()
Date: October 06, 2018 07:24PM

Hi Bruce, I agree it is unfortunate that you’re experiencing these symptoms in such short time and I’m as curious as everyone else to know what the real problem is. From what you’re describing, “the creaking throughout the car when turning while coasting” that sounds like a common posi noise from the clutch plates but that still doesn’t explain the dragging and hard shifting. The oil leak without any loose bolts or drain plug kind of assumes a crack in the case somewhere but I’m only guessing at things at this point. You have the right original parts, pinion shaft and all and I remember that everything in your differential was in like new condition. That along with the billet steel side cover you have should make this differential stronger than most.

Not saying something inside didn’t break but if so I would like to know why and where just so we could pinpoint the week link. Aside from the hard launches and that being what it was built for it should hold up to some abuse. However if there’s something I’m doing in my process that’s not working as it should I would like to know what it is. Anyway, there are all kinds of possibilities here but until you pull it apart we won’t know for sure so please keep me posted. And nice looking car by the way -Thanks

Regan Metcalf
Portland, OR

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Re: Trans problemconfused smiley. Help needed
Posted by: 7004doorL ()
Date: October 06, 2018 08:18PM

Noise only in the top gear indicates there is something wrong in the Diff. with regular cars?

In Propeller shaft or front engine cars?

And noise in 1st, 2nd, and 3rd gear is a transmission problem?
In propeller shaft cars.

Is it the same for Corvair?


Mike
1960 4 Door
80 HP PG

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Re: Trans problemconfused smiley. Help needed
Posted by: 66vairman ()
Date: October 07, 2018 09:08AM

So it was a POSI housing. Many have said the early POSI housings were weaker than the "open" differential. The LM housing was reinforced.

It will be interesting to see if the spyder/POSI housing failed.

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Re: Trans problemconfused smiley. Help needed
Posted by: flat_six ()
Date: October 09, 2018 12:44PM

When you dump the clutch on a Corvair, you put huge shock loads through the drivetrain - far greater than the Camaro parked there behind you does. That is because of the rear weight bias and traction. This overloads just about everything, not just the diff spider gears. I learned this lesson back in high school: don't try to keep up with the Camaro crowd in the burnout department. Get on a track and outrun him in the corners!

Great looking car by the way.

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Re: Trans problemconfused smiley. Help needed
Posted by: caroseiii ()
Date: October 10, 2018 02:43AM

Its very interesting. The differential is likely the problem as noted by others. A bent Input Shaft could explain the early gradual noises and grinding while shifting but that would not explain the severe noises while turning. Make sure to take some photos of the stages of disassembly to assist Regan.

Crawford Rose

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Re: Trans problemconfused smiley. Help needed
Posted by: WCcorsa ()
Date: October 10, 2018 02:56PM

Flat six is spot on!

Forget burnouts. Any car with no weight in the back (Camaro) can do a burn out.

Turns are the ticket for winning against muscle cars.

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Re: Trans problemconfused smiley. Help needed
Posted by: bruces ()
Date: October 14, 2018 12:32PM

Just an FYI, The 1st gen Camaro has 1460lbs over the rear. That's more than my Corvair. Also weighs 900lbs more... That's more parasitic stress than on any Corvair. Also, big block V8 torque creates a much greater induced stress than a Corvair can produce. If a 911 can launch hard without fear of exploding the diff, why can't we?
Just frustrated....

Bruce S
'68 Monza Coupe
140 Turbo EFI
White Rock, BC



Edited 2 time(s). Last edit at 10/14/2018 12:34PM by bruces.

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Re: Trans problemconfused smiley. Help needed
Posted by: MattNall ()
Date: October 14, 2018 12:58PM

Who told you that? Lots of Beef up parts for Porsche as well as VW..





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..............................110-PG.................................................Webered-Turbo

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Re: Trans problemconfused smiley. Help needed
Posted by: steve c goodman ()
Date: October 14, 2018 02:40PM

Camaro is very light weight in the rear. Watch
them stuck going downhill around here when it
snows. Owners put weight in rear/studded rear
tires and still terrible. When Camaro puts power
to the rear wheels even on dry road the tires
simply spin after traction limit is reached.
Big difference in r/p dimensions too.

A Corvair has great traction on
rear, very difficult to spin rear tires;
something is going to break.

Cannot compare Porsche and Corvair either.
P-cars are engineered on the race track.

As suggested above if you want to embarrass
most front engine cars find a twisty road.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC

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