Transmission pan leak and intake manifold gasket problem

Biggredd2069

Biggredd2069

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I have a 68 newport convertible with 383 4 barrel Carter carb. I had a leak in the transmission pan and changed out the filter and gasket, used a torque wrench at 10 lbs. Leaking worse than before and now I over tightened and it's bulging out a little. A local shop wants $250 to repair. Would rather try again. I have extra fluid and the I have extra pan gaskets. My question though is one gasket I had was relatively firm and seemed good but it's more likely ruined. I have two really floppy ones that came with the filter I bought. Should I try just using one of those? Need some advice.

Also they said I have a leak in the intake manifold gasket and l need a new carburetor. They'll happily do it for 1800 bucks. No thanks. Wondering next best steps, opinions. Torn between keeping this engine with a mild cam upgrade and making it nice, or swapping to a 440? Or upgrade to electronic fuel injection?
 
WINCE.GIF
 
First, Check the transmission case for leaks around the shift linkage. Also check the lower cover for the transmission bell housing for a leak coming from the front pump. If you are then satisfied that the pan is what is leaking, remove the transmission pan and inspect it and the transmission case for obvious defects, be sure both mating surfaces are clean and reinstall the pan, the gaskets that come with the pan on quality kits should seal properly when properly torqued. Warm up the transmission and recheck the torque on the bolts as the gasket may compress some after it warms up. Check the pan for obvious dimpling around the bolt holes and flatten out any you find. Check the bolt holes for any debris that might keep the bolts from seating properly.

As far as the AVS carb goes, what makes you think it is in need of replacement? If the car just runs like crap, that may be the defective intake gasket. Start by replacing that. If you have reasonable mechanical skills, replacing the intake gasket is not all that difficult, main thing is to follow the FSM directions and be sure everything is clean before you start.

An AVS carb is also not very difficult to rebuild, most of the time you can get by with a thorough cleaning, a carb kit and new floats. $1800 is NOT a fair price to repair the gasket and replace the carb, you need to find a more reputable shop.

Dave
 
Get a pan gasket for an later model truck....say a 93 dodge ram with a A518....they have a much better gasket for those. I like to put a bit of RTV on both sides of gasket and let it set up for 15 min or so then install the pan, but as mentioned make sure it is not the shift rod pivot seal that is leaking....very common and a bit of a job to replace in the vehicle, but it can be done.

While you have the pan off I like to install a B&M universal drain at the RH front corner of the pan, beneath the dip stick tube....makes changing fluid and filter a much easier job in the future. ;)

Intake pan gasket is not that hard to replace, and a rebuild kit for your AVS is cheap so would try that first before anything else. The 383/4bbl is a great comb....I miss my 68 Coronet vert powered by that. The 440 is a good motor as well but the 383 just seems to be a little more versatile IMO.
 
I paid for an hour of diagnostic and they said there was something wrong with the flappers on the carb. Just found this out and I'll get more info when I pick the car up tomorrow. They did say some other places on the transmission were also leaking but this pan is definitely leaking. Thought I did a good job when I did it, obviously not. Lol. Got my work and money cut out for me. I don't mind a small leak but this is too much. As for the carb it kinda wants to stall when I floor it but then evens out and accelerates fine.
 
On the pan gasket, if the newer A518 gasket is better and fits, use that. PLUS the sealer on each side, which will help account for any possible minor sealing surface issues.

It's highly possible that, even with the torque wrench, the new pan gasket could have been split when it was torqued-down. I have used just normal "snug", in sequence, with good results. Discretion is the better part of valor, here! Make sure where the other seeps are coming from, too.

As for the intake manifold gasket, they don't just fail or blow out. They're beaded metal. Normally don't rust, either! Check the intake manifold bolts' torque, for good measure.

The "flapper" on the AVS is the secondary air valve. The adjustment spring on it might be broken or just need adjustment. The carb is easy to rebuild. From many of the things I've been seeing about the self-learning EFI systems, many aren't all they're crackied-up to be. Issues with getting them programmed for the particular car and such, too. It's just a better fuel mixer on top of an existing manifold for a LOT of money, all things considered.

Get the trans leak taken care of and THEN worry about the carb. Neither is probably very hard to fix, very possibly. Of course, when you pay somebody else to do the job AND/OR diagnose it, $$$$$ signs can fly out of your wallet. There are some of the Chrysler MasterTech videos on several websites, one of which should detail the Carter AVS carburetor (how it works and how to work on it).

Just some thoughts,
CBODY67
 
The tranny pan is a simple, wipe it off, see where it leaks, then chase those areas, better pan gasket if it works, and your done. And an AVS is simple to fiddle with, Google tuning an Edelbrock carb, and watch a YouTube video, they are child's play, easy, simple, safe. You can do all this in a day over the weekend and save some money for beer. Get to know your car, bond with it and learn. These old rides are simple and you can tear down and build one mostly with hand tools. Buy a Factory Service Manual (FSM) and follow it for directions. And have fun.
 
Biggredd2069 said:
They'll happily do it for 1800 bucks.
Click to expand...

$1800 is the "this is a PITA and if we quote enough he'll go away" price.

Regarding the carb, get in touch with this guy @Dana . Just Bought A Carburetor Shop
and send the carb to him. You need someone that knows those carbs to fix it and get it right to begin with. Don't screw with the fuel injection. You'll get over your head real fast.

The trans is most likely leaking around the shift linkage as was said. It leaks there and drips down and appears to be the pan. Unless your mechanic is familiar with the 727 trans, chances are they don't know that.

Intake manifold gasket? Hmmm... Never saw a real issue with a 383, but you never know... Anyway, it's an easy fix. A bunch of bolts to take off and put back on.
 
Your right about the go away price. I do have the fsm on disk. I'll double check the shift linkage. The car runs as is so luckily I have that. Was hoping it could've just been an adjustment needed, not a rebuild. I may check into a new intake and been with a little more performance is that's worthwhile. I'll be getting dirty again soon with it.
 
Leaking Trans Pan:

For my 1972 727, the torque spec was 150"lbs so you may be under tightening the bolts by 30"lbs (2.5'lbs)

My leaking 1972 727 trans pan, 1st 3 gaskets: I used cork gasket, rubber NAPA gasket, and then rubber NAPA gasket with sealant. (RTV did not stick to rubber gasket) Still had leaks. 4th try: Went with Mopar P3690730 trans pan kit, Moroso 93110 steel core gasket, and 3/4" inch thread length bolts (compensates for thicker gasket by adding 1/8" thread length). I used no sealant and thus far have no leaks. If all else fails...

Moroso 93110 Perm-align Transmission Gasket for Mopar T/F 727 Engines 84663931109 | eBay
s-l500.jpg

New NAPA filter and P3690730 adapter
20181122_085244.jpg

P3690730 pan painted black and Moroso 93110 gasket
20181122_102443.jpg
 
One other place the trans leak/seep might be coming from is the seal around the base of the trans dipstick tube. In any event, get a spray can of brake cleaner and wash it all down. Then look for "trails" of fluid after it has sat un-run for a day or so. If nothing, then start it up and run it for 30 minutes or so, or a drive of a similar time. Then get a big piece of cardboard and park the car over it so it's under the transmission. That can help locate the place the drips are coming from. Look for them, on the trans case, with a bright light.

Leaks from the dipstick tube seal usually are not an issue, unless somebody's put a normal o-ring seal there rather than one designed to be there. Rubber compounds are not all long-term atf retention items, by observation.

The A518 pan gasket looks like it might have a certain amount of re-usability in it. The use of "sealer" is not particularly for the decrease of leaks, but to make removal and related clean-up easier, especially on a non-rubberized cork gasket. Looks like it might be more resistant to "squishing" from over-torque, too.

IF the leak/seep comes from the tail shaft housing, there's a lip seal back there, BUT it usually has no issues unless the bushing back there is worn. New seals will last only a shorter time as the nose of the driveshaft can waller it out. Change them together. Should be able to do that in the car, with the proper tools.

The ONE time I thought I had an intake leak on my '67 Newport, I pulled it all apart and found NOTHING of that sort. Sealed it all back up again with sealer and the paper 6-Pak gaskets, so I knew it was better and not an issue. More likely the intake manifold bolts are an issue than a deteriorated metal valley pan gasket, I suspect. A bolt as little as 1/4 turn loose can cause "leakage". Ways to test for that without any disassembly!

Me suspects the shop didn't want your vehicle in their shop. Nothing against the car, just the mechanics' expertise on older vehicles they knew little about. Many suspect that if they get one in there, others will follow, it seems. Having a stall tied up while waiting on parts is a concern of theirs' too, but then they can easily have worse issues with newer cars, by observation.

Plug in the FSM disc and start learning. It'll be fun and rewarding!

CBODY67
 
Biggredd2069 said:
I like that molded one. Do you still use a sealer?
Click to expand...
That's a good question. Myself, I wouldn't as I understand these gaskets are intended to be used without any sealer.

There's always personal preference and some will use some sort of sealant. If you do and decide to use RTV, at least get the Permatex RTV for automatic transmissions. It's my understanding that the trans fluid won't let the RTV cure correctly. If I were to use a sealer, I'd lean towards using "gorilla snot" 3M yellow weatherstrip adhesive or maybe just plain old spray on Permatex red sealer.

YMMV
 
Dan Scully said:
The trans is most likely leaking around the shift linkage as was said. It leaks there and drips down and appears to be the pan. Unless your mechanic is familiar with the 727 trans, chances are they don't know that.

If you use this tool ,you can do it all from the outside . It comes with the remover , installer and seal

View attachment 233351
Click to expand...
Have you ever used that tool? I have to replace the seal in my car and I've seen that tool but never read of how to use it and if it works well.
 
Dobalovr said:
Still available from your local Dodge Dealer......
Click to expand...
The local dealers are really hard to deal with. Back when I had contacts in the local dealerships, I bought a lot of stuff at the local places. When Chrysler shut down a bunch of dealerships, I lost any decent parts counters. The guys at the parts counters that I've encountered have zero knowledge, zero desire to wait on a walk in, and zero desire to even think about helping someone with an old car.
 
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