Oh No another leaky T-350 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Transmission - Rearend
User Name
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 11-25-2012, 10:21 PM
bentwings's Avatar
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 75
Posts: 2,154
Wiki Edits: 0

Thanks: 3
Thanked 96 Times in 82 Posts
Oh No another leaky T-350

I went through all the T-350 info on the search but didn't come up with this one.

I have about 20k on my rod. The trans was built about 9 years ago and I have been driving it 4 years. It has Kolen clutches and a heavy duty sprag assembly and a 3000 stall converter. There were a number of leaks along the way.

A new bullet and speedo gear set fixed that one. It has not leaked a drop from there.

New rear seal a couple years ago fixed that.

Lokar locking dip stick fixed that leak.

New steel o-ringed plug for the missing kick down cable fixed that one.

New pan gasket seems to have fixed that one.

The servo does not leak.

Vacuum modulator was replaced with another adjustable one....no leaks now.

Shifter shaft only leaks a drop or two once in a great while. Lokar shifter.

Cooler lines have new hoses last spring. I have triple clamps on each side of the lines from the trans to the cooler lines. 12 clamps total. This has been a major source of leaks of late.

Lines at the trans cooler are AN and do not leak. The cooler is a little above the trans pan and is in front of the radiator. There is no cooler in the rad.

The area between the pump and converter is dry. Even the converter is dry.

I just had the floor tunnel out and cleaned the top of the trans. Mostly dust and road dirt. The vent area was dry.

For the last 3 months there has not been a single drop of trans fluid or any fluid for that matter on the floor.

Then I come in last Sat at 6 AM to pick up the car for the morning breakfast and cruise and there is a huge puddle of trans fluid on the floor. I'd guess about 1 qt. 6 feet in diameter.

Now in the past when the guys at the shop push the car backwards I have noticed it will leak a little fluid. It seems around the pan. It will show a good qt over filled on the stick untill I start it, then it goes to about 1/2 low where I usually run it cold.

According to what they said Sat they only rolled it ahead so I could get out in the morning.

After the Sat run I parked it again in the same spot. Then about 8 hours later I pushed the car backwards about 30 feet and let it sit over night.
I came in about 12 hours later and dogone if it didn't leak a bunch again...this time into my cookie sheet.

Anybody got any idea what is going on??

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 11-26-2012, 12:11 AM
Last photo:
Join Date: Nov 2012
Posts: 2,482
Wiki Edits: 0

Thanks: 173
Thanked 363 Times in 332 Posts
look at the front seal..
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-26-2012, 05:50 AM
Irelands child's Avatar
Registered User
Last wiki edit: Ford engine specifications Last photo:
Join Date: Jan 2005
Location: Upstate New York
Posts: 5,368
Wiki Edits: 8

Thanks: 59
Thanked 530 Times in 410 Posts
Sounds like my trials with a Ford C4 over the past 3 years

I'm on my 4th dipstick - 3 Lokar's, two of which were warranty replacements. Now have a locking Hughes which so far doesn't leak. You might want to again look at the Lokar dipstick. Those 0-rings(I 'assume' you have the 2 O-ring version, if not, Lokar will probably replace it under warranty). Those O-rings possibly could be replaced with the next larger cross section ring. After I put the Hughes dipstick in dragged out my spare C4 and checked the fit - it could be better.

Transmission pan bolts - conventional hex bolts leaked. Badly. I replaced them with washer head as well as some sealing washers. That leak is gone plus I torqued them to the low end of the spec.

Transmission pans - after four different brands(Ford OEM and SVT, TCI, and another, name now forgotten) ended up with a very nice aluminum Trick Flow that wont bend while being torqued to spec

Pan gaskets - cork now leaks. For many years, I used only cork and successfully. Now, it has to be fiber that wont disintegrate/spread out. I'm guessing that manufacturers are now using shredded cork and binding it with a glue of some sort rather then sheet material

I still have a very minor front seal leak - and that might just leak forever unless I pull the engine-transmission someday - then I still might not 'dig in'.

Good luck, and let us know

Dave W
Irelands child
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-26-2012, 07:13 AM
cobalt327's Avatar
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Posts: 5,031
Wiki Edits: 1616

Thanks: 128
Thanked 616 Times in 565 Posts
I have had the exact same thing happen! Here's my story:

The car is a 1980 Malibu w/a TH350C. Has a little over 100K miles on the original tranny. I am the second owner (since 12K miles), so the history is irrefutable. It shifts perfectly, lock up works, no probs w/it ever- except the occasional huge leak.

With my car this only happens after it sits w/o driving it for a couple weeks. My GUESS is that the torque converter is somehow draining back into the tranny, causing the tranny to be overfilled. Then it leaks until the levels match.

Now all the tranny gurus can flame me for this being impossible.

BTW, I have a 1994 Sierra w/the 4L60. It does this same thing, and it too only dumps on me after sitting for a long time w/o being used.

If this is even possible, I don't know what the fix would be.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-26-2012, 08:06 AM
rick 427's Avatar
Registered User

Last journal entry: 33 WILLYS
Last photo:
Join Date: Feb 2012
Posts: 376
Wiki Edits: 0

Thanks: 0
Thanked 36 Times in 36 Posts
cobalt327...it IS possible....it's called drainback....It occures when the pump bushing gets worn,or [more often] a rebuilt torque converter hub is slightly undersized...over a period of time,the fluid will drain back from the converter thru the hub/pump bushing area,thru the cooler line,and back into the trans,yet the front seal,as it can still have a good fit on the hub, will prevent the fluid from coming out the front of the trans. A tell tale sign is by an overfilled reading on the dipstick before start-up, and a normal level after start-up.I mostly saw this condition in the Chrysler products,for some strange reason,but,rarely, have seen it in others also. Mopar started putting anti-drainback valves in the oil return cooler line a while back on their trucks right from the factory. I've put those valves on a few older mopars with success,but never tried it on any other make car,since it happened so rarely,that the boss would just just have the guys pull the trans and have me change the pump bushing and converter,so I really can't say FOR SURE if it would be a fix for Ford/GM's, but I think I would find a flow chart,and if it looked like it would work, give it a try if the car was in my liftless garage at home.
Reply With Quote Quick reply to this message
The Following User Says Thank You to rick 427 For This Useful Post:
cobalt327 (11-26-2012)
  #6 (permalink)  
Old 11-26-2012, 08:42 AM
cobalt327's Avatar
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Posts: 5,031
Wiki Edits: 1616

Thanks: 128
Thanked 616 Times in 565 Posts
This is the first time I have read any verification, and your description makes sense to me. Much appreciated.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 11-26-2012, 10:09 PM
bentwings's Avatar
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 75
Posts: 2,154
Wiki Edits: 0

Thanks: 3
Thanked 96 Times in 82 Posts
There is no doubt that I have "drain back". It's done this since I installed it. The converter is an aftermarket 3000 stall. ( unblown), they weren't very happy that I was using it in a supercharged car. It works very well and I don't abuse it often.

The Lokar dip stick is now suspect. I didn't know about the doube o-ring. Mine is an early one. I don't even think they were advertized when I got it. I'll clean everything up around it again and look more closely.

The pan gasket is a cork one. I did carefully torque the bolts. The self sealing bolts seem like a good idea. Have to check McMaster for some of these. I'm going to check the auto parts store for a solid pan gasket. We have a large trans supply house in town so I can check there too. I did check the pan bolts and they were all tight but it is a bit wet around the front of the gasket. I have a trans temp sender in the front of the pan but it seems ok. I need to look closer at it this week end.

Now this anti drain back valve in the cooler line....first, what is the part number and where can I get one??.

My cooler line are 3/8 dia and quite long even for a small car. The cooler is pretty large too so I would guess there is almost a qt of fluid in the system.

Thanks for the help guys.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 11-28-2012, 09:24 AM
Registered User
Last photo:
Join Date: Jun 2010
Location: Syracuse, NY
Posts: 3,848
Wiki Edits: 0

Thanks: 3,099
Thanked 655 Times in 540 Posts
I had a faulty reman torque converter do this to me once on a turbo 400 in a plow truck (late 80s/ early 90s C1500 'camper special' with helper springs and a V6). Ugh what a wonderfully reliable yet utterly awful POS. It just wouldn't die.

I forget the brand of reman TC; I had heard recently that there were 'lots' of people on the 'net having issues with the brand; I want to say Pro-King, but I'm not 100% as that could have been the brand that had replaced the faulty one
Reply With Quote Quick reply to this message

Recent Transmission - Rearend posts with photos

Quick Reply

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
leaky holley bigtim Engine 0 04-22-2007 04:54 PM
leaky intake bigtim Engine 3 06-18-2006 11:09 AM
LEaky C-4 nitrous_69stang Transmission - Rearend 5 02-18-2004 11:17 AM
Leaky C4 nitrous_69stang Transmission - Rearend 3 08-03-2003 11:18 AM
Leaky C4 falcondude Transmission - Rearend 1 12-23-2002 07:55 AM

All times are GMT -6. The time now is 07:20 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.