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700r4 pan will not win !

Lunatic

1/2 ton status
Joined
Jul 27, 2008
Posts
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Location
Ft Hood, Texas
I can not get my pan to seal for more than a day.

I have tried numerous gaskets types firstly, have checked for oddities on the trans mating surface, cracks in the housing, pan issues......

The only thing I can think up at this point is it (the trans) isnt breathing properly, which is forcing the gasket to blow after a certain amount of running.

Fresh pan installation - I ran to work yesterday morning, roughly 80-85 outside. No leak once parked at work. I drove home after work, roughly 105-07 outside - The leak returned, as always, at the pass rear corner.

I wiped and tightened what turned out to be pretty dam loose bolts after already being checked twice prior to the inital fill. Wiped everything off, ran and drove to work this morning (under the same conditions) - I didnt even bother checking once there.

I drove home tonight, and assuming the drip had returned, grabbed a rag after pulling into the drive, wiped everything down again (go figure), dropped a drip pan, and went inside. I had to wait for the everything to cool way down (true 3" duals with Flowtech headers is a tight fit - Even the pan is too hot to touch.)

So......After dinner, I went out to the driveway, checked the temps by hand, and then noticed that the minor drip wasnt so minor anymore. I was happy I had dropped the drip pan earlier - I think I lost about 3 quarts in the time I was inside. I checked for loose bolts once again and found a few, tightened a few - The drip became a flow.

So, I drained the pan, pulled all but two bolts, and walked away.

I tried to pull the breather tube at the top of the trans but it wouldnt give. I need to make sure it's clear, and Ill be re-checking everything again tomorrow evening as well.


But, dam - What else can it be ? Any additional ideas would be helpful.





Lunatic
Ft Hood, TX
 
I was starting to think the same - Heat playing a role.

I have been designing some custom heat shields for the entire run of exhaust, but havent installed anything to this point.

I'll post some pics shortly - Being dark outside it is difficult to say how visible anything will be, or what the pics will provide to you for insight. But stand by - They will be up shortly (tonight).




Lunatic
Ft Hood, TX



I'd say theres no more than 3" in the closest area of either side.


And before anyone thinks to point it out - Yes, there is RTV present - Yes, there is even CORK present. I did say above - I tried a variety of variations to no success. Desperation leads to trying almost anything once.


DSC_0001.JPG


Direct link pass side


DSC_0003.JPG


Direct link driver's side
 
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i had this problem on my 700 when i switched to an aluminum pan, ended up going and talking to the local trans shop and they gave me a steel ridged rubber (i believe) gasket and it took care of my gasket blowing out the side issues.
 
Thats something else I was thinking.

My engine oil pan and valve covers are sealed with Fel-Pro rubber/silcone gaskets which have steel sleeving - I just havent been able to find one or know where to continue looking for one, for the 700r4.

I guess I could shoot through some trans shops - Im sure it will be pricey though. :doah:



Lunatic
Ft Hood, TX
 
i dont know what they cost sorry on that one, they gave it to me cus my shop always drops off trannys for them to rebuild.
 
Thats something else I was thinking.

My engine oil pan and valve covers are sealed with Fel-Pro rubber/silcone gaskets which have steel sleeving - I just havent been able to find one or know where to continue looking for one, for the 700r4.

I guess I could shoot through some trans shops - Im sure it will be pricey though. :doah:



Lunatic
Ft Hood, TX

I think that would solve your problem, sure did on valve covers and oil pan.
What brand pan do you have?

Wayyyy long shot, how are your drivetrain mounts?
 
how much RTV did you use when installing the pan?

i usually don't use any on the mating surface of the trans, i will put a very light coating on the pan itself just as an adhesive for the gasket, but that's it and i haven't had any problems with them leaking.

oh, and the high temp black stuff too.
 
Trans mount is new - Feb09 - and hasnt seen dirt yet. Engine mounts are questionable, but do not apply to this issue.

The pan is a shady LMC x-deep (Which may be part of the problem) - Holds 8.5 quarts itself.

-----

How much RTV ? lmao - a whole tube ! :haha: But I dont use RTV on gaskets.......so.......one tube....seemed enough.

I didnt just hash it down though. I simply put in the bolts and finger snug, moved onto something else for an hour, went back and snugged them torque tight, moved on another hour, then double checked the tightness. I basically blew it out tonight when tightening again, thus the drip to a flow thing. I knew it was coming, so no loss.

Wha ?? My RTV skillage needing some....learnin ? :D I dont use it too much.

------

Yeah, Kenny - I will admit to not doing a search - But thats because everytime I see a "700r4......" thread, I stop in. This is where the idea came from (past readings) and why I need to make sure my vent line is clear, which Ill do tomorrow evening.



Thanks for the continued replies !



Lunatic
Ft Hood, TX
 
cheep chrome and deep tin pans arnt worth crap for sealing.

oem tin or cast aluminum is the only way to go.

and rubber gasket i think is best. and both surfaces must be dry before bolting up tight.
 
I have yet to tackle my leaky trans pan. Most of my bolts look different and the pan looks like it had been beaten flat and then straightened and reused. I want a nice cast one.

The one thing you may want to check which I have seen cause a leak, when you drop the pan, check the mating surface on the trans for a gouge or scratch. Even someone who has cleaned an old gasket off with a wire wheel or whizzer can leave a scar that can wick oil.
 
I have yet to tackle my leaky trans pan. Most of my bolts look different and the pan looks like it had been beaten flat and then straightened and reused. I want a nice cast one.

The one thing you may want to check which I have seen cause a leak, when you drop the pan, check the mating surface on the trans for a gouge or scratch. Even someone who has cleaned an old gasket off with a wire wheel or whizzer can leave a scar that can wick oil.


+1 check mating surfaces with a straight edge, see if it's warped...
 
Thanks for the input guys ! It was one of the first things I checked.

....I have tried numerous gaskets types firstly, have checked for oddities on the trans mating surface, cracks in the housing, pan issues....

With the temps around here being in the 100s, it will most likely be next weekend before I return to this issue - I still need to fab some heat shields which may be accomplished prior to the weekend.

Hard to say.....:crazy:

I removed my cab carpet and insulation yesterday which presented another task to tackle - I have minor rust points on my floorboards needing attention.

Time for a welder :D





Troy B
Ft Hood, TX
 
What are you cleaning the mating surface's with. I clean both pan & trans w/brake cleaner. After i scrape of course. Also there is a hole on pass toward rear that never seams to stop leaking, so i wipe that hole just before i put the pan on. I do not use gaskets on trannys or diffs, just sealant. everything else your telling us sounds good. p.s. try sealant called "the right stuff'.
good luck
 
I don't know how tight you're cranking the pan bolts down. But if it's too tight it WILL leak. Only needs 9 ft/lb (108in/lb). If it's straight, clean, and your using a rubber gasket (not using a cork gasket), it won't leak. IMO, yeah the permatex stuff will work but it just makes a mess and is that much harder to scrap off next time. If you use permatex, it's just a bandaid to a bigger problem. But once again this all just opinion.
From looking at your pictures, you've got an early early 700r4. Unless you drilled/tapped for that sending unit.
 

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