67 GTO with leaking transmission; automatic - Pontiac GTO Forum
User Tag List

 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old 04-26-2012, 05:15 PM Thread Starter
 
Join Date: Oct 2011
Location: Coral Springs, FL
Posts: 50
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
67 GTO with leaking transmission; automatic

I have leaking auto transmission; model turbo 400. Iím starting with the basics; oil pan gasket. There is a 4 inch plastic tube which connects to the filter with a rubber gasket then travels to an orifice within the trans. This end does not have any kind of gasket. Does anyone know if a gasket belongs here?

Also; is there an aftermarket tranny pan for this vehicle that has a drain plug? The original does not; therefore, tranny fluid spills everywhere.

Thank you,
Jim

I tried to insert a picture but received a script errorÖwhatever that means. No time to trouble shoot this error; time is valuable; Iíd rather get my Goat running.
jimmy328 is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 04-26-2012, 06:10 PM
64-67 Expert
 
geeteeohguy's Avatar
 
Join Date: Feb 2008
Location: Fresno, California
Posts: 8,556
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 119 Post(s)
There is an "O" ring that goes around the plastic tube and holds it in place in the trans. Try the aftermarket for a drain-plug pan....
geeteeohguy is offline  
post #3 of 7 (permalink) Old 04-26-2012, 06:21 PM Thread Starter
 
Join Date: Oct 2011
Location: Coral Springs, FL
Posts: 50
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Continuing research I’m now realizing there are other areas of potential leak…rear seal, front seal, speedo cable, and modulator o-ring. What is a modulator o-ring? Where do I find it? Is that the plastic tube I referred to?
jimmy328 is offline  
 
post #4 of 7 (permalink) Old 04-26-2012, 07:33 PM
64-67 Expert
 
geeteeohguy's Avatar
 
Join Date: Feb 2008
Location: Fresno, California
Posts: 8,556
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 119 Post(s)
The modulator is that canister looking thing the size of a spool of thread on the right side of the trans with the vacuum line going to it. The most common place for a TH400 to leak, in my experience, is the fill tube that attaches to the back of the right cylinder head and leads into the transmission. Very common for the O ring to dry up and let fluid slosh out and work its way down the trans around the pan (looks like a pan gasket leak). Be sure to straighten the pan rails so they don't dip between the holes (use a ball peen hammer and a solid backing for a dolly) and be sure that the pan rails are straight and clean. Do NOT over tighten the pan bolts (I use a nut driver a lot of times), clean, and re-check.
geeteeohguy is offline  
post #5 of 7 (permalink) Old 04-26-2012, 07:50 PM Thread Starter
 
Join Date: Oct 2011
Location: Coral Springs, FL
Posts: 50
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks so much GTOTEE. I now know exactly what the modulator is and will replace this gasket.

I notice a rail that encircles the pan and it looks fine; however, I am buying a new one with a drain plug. Perhaps from Summit; don’t know yet.

As for the fill tube removal; I disconnected the bolt near the back right cylinder. Should I use a rubber mallet from beneath the car to tap it out?

Your help is greatly appreciated.
Jim
jimmy328 is offline  
post #6 of 7 (permalink) Old 04-27-2012, 10:08 AM
64-67 Expert
 
geeteeohguy's Avatar
 
Join Date: Feb 2008
Location: Fresno, California
Posts: 8,556
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 119 Post(s)
The tube should pull right out. A twist should do it. If a rubber mallet or a wood drift is needed, there you go. It sounds to me like this is new to you, but you have the good sense not to go in blind and seem to have the common sense not to force things. Excellent. Go slow, ask questions, and also, I'd recommend getting a reproduction '67 GM service manual, or a '67 Motors manual. That'll be a huge help. Also, don't get a chromed pan....they tend to leak prone. I would leave the shift shaft seal alone at this time. It can be a real chore to get it replaced, and if it does need replacing, it can be done when it's all back together due to its location with minimal fluid loss. Good luck.
geeteeohguy is offline  
post #7 of 7 (permalink) Old 04-27-2012, 11:42 PM
 
Join Date: Mar 2011
Location: Texas
Posts: 704
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
a better approach is to put a clean cardboard down underneath the trans and figure out where the leak appears to be coming from. that would help narrow down the area to look at. However, if your trans after a road trip and has been sitting for awhile then is leaking, that happens to a lot of them. that actually is not a leak requiring a fix, that is due to inactivity and seals will stop leaking once the trans gets hot and is run for a time.
pontiac is offline  
Sponsored Links
Advertisement
 
Reply

  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Undercarriage, Frame, Transmission and Differential Discussions.

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pontiac GTO Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Automatic to Manual Transmission conversion. JESchulte 1964-1974 Tempest, Lemans & GTO Undercarriage, Frame, Transmission and Differential Discussions. 8 08-02-2016 04:38 PM
Automatic transmission fluid for power steering? iwant2buyaGTO Service, Maintenance and Technical Discussion 5 02-09-2012 08:25 PM
Transmission Leaking Jim 1964-1974 Tempest, Lemans & GTO Undercarriage, Frame, Transmission and Differential Discussions. 2 03-18-2009 10:18 PM
Automatic Vs. Manual Transmission drosene Service, Maintenance and Technical Discussion 17 09-11-2007 05:06 PM
Transmission Case Leaking ?????? Dragon 32 Service, Maintenance and Technical Discussion 4 11-02-2006 07:09 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome