unusual 4+3 problem
Thread Starter
Drifting
Joined: Dec 2001
Posts: 1,313
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From: providence ut
unusual 4+3 problem
OK .........5,000 miles on a complete rebuild, two years ago...last summer the overdrive fuild started coming out the air breater hole in the top side of overdrive..........4 speed lube oil was coming through the oil seal between the 4 speed and overdrive, thus over filling the overdrive and emptying the 4 speed unit...AMCO replaced the seal at $400.00 (only an 90 day warrenty)....now 2,000 miles and 1 year later same thing............whats causing the oil seal to fail? if the shaft was bent I would feel it...........shaft flexing?.........rough spot on shaft? loose bearings in the housing?....they want to replace the seal with a differrant brand seal..........I'm already into the trans $2,000.00..what I'm looking for is a shop that does alot of 4+3's.. ..if there is one....that might have experianced this problem.........I don't have any faith in just replacing the seal, something is causing the failure.....maube it's just too much horse power.
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
OK I m on my way with a hacksaw, you get the ZF6 speed and witha little surgury, we'll bang this out!~
Just kidding, here are two
http://www.corvetteobsession.homeste...formation.html
Just kidding, here are two
http://www.corvetteobsession.homeste...formation.html
Thread Starter
Drifting
Joined: Dec 2001
Posts: 1,313
Likes: 1
From: providence ut
that's just the reason I'm keeping close tabs on your ZF 6 speed post 
...I just went into one of the sites and it said 400 hp was too much for the 4+3.....dam.......I just droped $7,500 into a new engine........If I buy a new trans the wife will cut my yoo hoo off 
...I just went into one of the sites and it said 400 hp was too much for the 4+3.....dam.......I just droped $7,500 into a new engine........If I buy a new trans the wife will cut my yoo hoo off
Drifting
Joined: May 1999
Posts: 1,478
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From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
The problem is more likely the rebuilder not using the latest redesigned components and properly protecting the seals during assembly; not the horespower. Go to David Fulcher's 4+3 write-up at the Corvette Action Center. URL=http://corvetteactioncenter.com/kb/question.php?qstId=115 Dave used to post on CF in the past. He knows Corvettes and the 4+3. I'd talk to him.
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Originally Posted by ZylaRace
400HP,... say's who?
The twin turbo Callaway used a 4+3 trans.
The twin turbo Callaway used a 4+3 trans.
But, FWIW, everyone I called, S&K, Darrels, Gearzone, they all said that the 4+3/OD would only break again on may car with the 385-RWHP/ 405-RWTQ,, so I could not see plunking down $1300 for this time and possible then having it go bad again,
No one would recommended that I repair it and reuse it.
Safety Car
Joined: Jun 2003
Posts: 4,509
Likes: 240
From: Coconut Creek FL
Originally Posted by ld85
But, FWIW, everyone I called, S&K, Darrels, Gearzone, they all said that the 4+3/OD would only break again on may car with the 385-RWHP/ 405-RWTQ,, so I could not see plunking down $1300 for this time and possible then having it go bad again,
No one would recommended that I repair it and reuse it.
What he said! My 84 4+3 was crap- the car only has 47K miles on it...and the carrier bearing went...both oils mixed and the rest is history...go with the ZF (I did) and it was the best mod to date...the car is a whole new animal!
Race Director
Joined: May 2003
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Originally Posted by Mike_88Z51
The problem is more likely the rebuilder not using the latest redesigned components and properly protecting the seals during assembly; not the horespower. Go to David Fulcher's 4+3 write-up at the Corvette Action Center. URL=http://corvetteactioncenter.com/kb/question.php?qstId=115 Dave used to post on CF in the past. He knows Corvettes and the 4+3. I'd talk to him.
I too plan on building my motor upo mikey.....heh long time no talk, you can always call ontario if u want.....i did call u about 2 weeks ago, but no answer! umm, how's the car running? have u had in out at all?
i hope my 4+3 last, i do LOVE it over the 6 gear I had, but I just hope it last when I start upping the HP antey.
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Thread Starter
Drifting
Joined: Dec 2001
Posts: 1,313
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From: providence ut
Originally Posted by Mike_88Z51
The problem is more likely the rebuilder not using the latest redesigned components and properly protecting the seals during assembly; not the horespower. Go to David Fulcher's 4+3 write-up at the Corvette Action Center. URL=http://corvetteactioncenter.com/kb/question.php?qstId=115 Dave used to post on CF in the past. He knows Corvettes and the 4+3. I'd talk to him.
I bought the parts from gear ventor in FL..they were the up dated parts, them took them to Amco to install...I knew they would have no Idea were to buy them................the mechanic had never seen this type of transmission before, he did say he enjoyed something differrant and I also took in my GM overhaul book as a referance along with the trans book he had......anyway I'm in a world of hurt now........ya know once you cross the line with high proformance engines it's just part of it ...blower...nitrous.....next I'll start toasting the brand new clutch.
Race Director
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Originally Posted by lead foot 85 vet
I bought the parts from gear ventor in FL..they were the up dated parts, them took them to Amco to install...I knew they would have no Idea were to buy them................the mechanic had never seen this type of transmission before, he did say he enjoyed something differrant and I also took in my GM overhaul book as a referance along with the trans book he had......anyway I'm in a world of hurt now........ya know once you cross the line with high proformance engines it's just part of it ...blower...nitrous.....next I'll start toasting the brand new clutch.
Thread Starter
Drifting
Joined: Dec 2001
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From: providence ut
Just talked to gear ventors tech..........he said the bearing behind the oil seal is walking forward on the shaft and taking out the oil seal, usualy caused by excessive heat and a bad overdrive unit... He asked if reverse was chattering......no...asked if it pops out of secount going down hill...no......asked if the mechanic pounded the bearing back in on the secound oil seal install.........I don't know......I asked if excessive horse power was the cause..........he said they build for linginfelter and callaway and they hold power well but do not put it in over drive at low driveshaft rpm only high driveshaft rpm because the transmission fluid pump works of the driveshaft and that will kill an overdrive. anyway now I know why.....but why after only 5000 miles. will see if AMCO transmissions stands tall on this.
Le Mans Master
Joined: Dec 2002
Posts: 5,270
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From: Seattle Area WA
Scorp is running his with a good amount of power (not sure exactly) But it is beyond what all the rebuild shops said it could take. No problems as of yet as far as I know. I will be doing the same thing.
I am sure it won't handle it long if you never change the fluids, it had a bad life, and or you don't manually clutch the auto shifts. But I believe with manual clutching the auto tranny on and off, the only thing that should really wear is your 4speed. And super T-10s, not exactly wussy transmissions.
Sorry to get O/T but I hear SK Speed is good with 4+3!
I am sure it won't handle it long if you never change the fluids, it had a bad life, and or you don't manually clutch the auto shifts. But I believe with manual clutching the auto tranny on and off, the only thing that should really wear is your 4speed. And super T-10s, not exactly wussy transmissions.
Sorry to get O/T but I hear SK Speed is good with 4+3!
Thread Starter
Drifting
Joined: Dec 2001
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From: providence ut
Locktite.............It was the bearing walking and taking out the oil seal, the AMCO shop called gear vender in FL. and they said to locktite the bearing to the trans housing, they also went trough the overdrive and said it was in good condition ( well of course it is, it's only got 5000 miles on it) anyway $288.19 later, thats one half the labor bill and all of the parts ( he ate the overnite deliverly) I'm back on the road and fairly happy...................not bad for a 90 day warrenty one year later, they could have stiffed me but didn't..........ONE BAD VETTE back on the road again. 