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Seized Fill Plug-4+3 OD Unit

McSnagg

Well-known member
Joined
Nov 26, 2006
Messages
59
Location
Nebraska
Corvette
1988 Triple Black Convertible Z52 4+3
Any ideas on how to remove a stubborn fill plug? I am servicing both the transmission and the 4+3 OD unit on my 88, and the fill plug will not come out on the OD unit. Tried carefully applying heat along with an 18" pipe wrench. No luck. I'd hate to break the housing.

Any ideas??????????????;shrug
 

3dale1

Well-known member
Joined
Mar 12, 2005
Messages
158
Location
PA
Corvette
65 convertible L-76
Wow, an 18" and it still won't go?

I'd try MANY heat/cool cycles along with intermittent tapping the plug with a small hammer to break any corrosion up.

PB blaster is good, but it doesn't sound like it'll help you much, but on the other hand, it can't hurt.
 

Victory Red C6

Well-known member
Joined
May 10, 2007
Messages
205
Location
Gibbon, MN
Corvette
2007 Victory Red Coupe
I have read stories that guys have used a candle to lube the threads on stuck plugs, bolts, or nuts.

First heat the plug, then put a candle on the heated theads and allow some to melt into the threads. Allow to cool and if everything works according to the plan should come right out. Sounded like it worked great for guys that I have read about trying it. Never tried it myself. GOOD LUCK!!!
 

LT4man

Well-known member
Joined
Jun 25, 2003
Messages
2,214
Location
Chicago
Corvette
96 Collectors Edition LT4
This has ALWAYS worked for me!

Try TIGHTENING the plug just a little. This will break the rust free. Should come out then.

I have done this with countless bolts, nuts and plugs.

Good Luck!

SAVE THE :w
 

McSnagg

Well-known member
Joined
Nov 26, 2006
Messages
59
Location
Nebraska
Corvette
1988 Triple Black Convertible Z52 4+3
OK....I've tried heat, tapping, tightening, swearing (complete with a few new ones) and 4 days of soaking with PB Blaster. Still won't budge.

Any new ideas?
 
C

CAJUN C4

Guest
Not enough space.

This Sucks...Probably no one has ever taken it out since day 1.Are the flats stripped? Can you still get the pipe wrench on it...? You only have a couple options.
1) Take the trans. out of the car.
2) get an extra large cheater pipe and hope for the best.I think the pipe plug would round off before you broke the case.
Hope this helps.That's why we use "Never Seize"
 

McSnagg

Well-known member
Joined
Nov 26, 2006
Messages
59
Location
Nebraska
Corvette
1988 Triple Black Convertible Z52 4+3
The flats are pretty well chewed up, but I can still get a pipe wrench on it. I spoke to a couple of transmission specialists today. They both recommended using a center punch around the plug, slightly dimpling the aluminum casing. Second option was to use an air hammer forcing the plug to rotate counter clockwise.

The plugs appear to have never been removed with only 14K mile on the car.
 

bill5674

Well-known member
Joined
Dec 14, 2003
Messages
183
Location
li ny
Corvette
1990
have run into alot of stuck plugs on truck trans and rears. Have always had good luck by getting the biggest adjustable wrench you can on the plug. take a lump hammer and while you pull smack the wrench...kind of works like an impact. i guess somebody must have tried and failed at removal before you bought the car.
 

G Winter

Well-known member
Joined
Aug 21, 2004
Messages
2,177
Location
NW Iowa
Corvette
1990 red convert 6 sp
Did you heat the plug or the case or both?
Try heating the case on one side of the plug while trying to turn it out.

Glenn
:w
 

McSnagg

Well-known member
Joined
Nov 26, 2006
Messages
59
Location
Nebraska
Corvette
1988 Triple Black Convertible Z52 4+3
Still no luck getting the plug out. Tried to rotate it out with an air hammer. Wouldn't budge. Not enough room to drill out.

Anybody know if the OD unit can be removed separately or does the whole transmission assembly have to come out?

Thanks
 

bill5674

Well-known member
Joined
Dec 14, 2003
Messages
183
Location
li ny
Corvette
1990
now its time to leave it alone.....with that mileage let it go.if and when it cause s trouble then worry about pulling it out.if it ain`t broke leave it alone........that is of course you didn`t drain before checking the plug.
 

McSnagg

Well-known member
Joined
Nov 26, 2006
Messages
59
Location
Nebraska
Corvette
1988 Triple Black Convertible Z52 4+3
It was drained first. Time to drill it out.
 

G Winter

Well-known member
Joined
Aug 21, 2004
Messages
2,177
Location
NW Iowa
Corvette
1990 red convert 6 sp
Use left hand drill bits and go progressivly larger. You might bet lucky and have it turn out with the drill.


Glenn
:w
 

McSnagg

Well-known member
Joined
Nov 26, 2006
Messages
59
Location
Nebraska
Corvette
1988 Triple Black Convertible Z52 4+3
I tried. No room for a 90 degree drill.

Looks like it's off on a flatbed to a shop on Monday. I give up.
 

C12345

New member
Joined
Nov 24, 2004
Messages
3
Location
Larkspur, CO
Corvette
1959, 1965, 1972, 1988, 1998
I had the same problem with my '88 4+3. Fortunately a local Corvette shop told me about a simple workaround. Before you put the pan back on reach up and push out the electrical feed through that is about the same height as the plug. There are just a couple of plastic tangs holding it to the case. Then fill throught the hole and snap the feed through back in. Actually easier than using the plug.
 

bill5674

Well-known member
Joined
Dec 14, 2003
Messages
183
Location
li ny
Corvette
1990
how about welding a large nut over the messed up plug. the heat will help brake the plug free.
 

McSnagg

Well-known member
Joined
Nov 26, 2006
Messages
59
Location
Nebraska
Corvette
1988 Triple Black Convertible Z52 4+3
YOU DA MAN!

I had the same problem with my '88 4+3. Fortunately a local Corvette shop told me about a simple workaround. Before you put the pan back on reach up and push out the electrical feed through that is about the same height as the plug. There are just a couple of plastic tangs holding it to the case. Then fill throught the hole and snap the feed through back in. Actually easier than using the plug.


Pulled the pan back off and I see exactly what you mean.

YOU DA MAN!!!!!;worship THANKS!!
 

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