1956 Ford Truck, C4 Tranny Pan Problems

['32FordNut]

Hello, can anyone tell me if I can get an aluminum C4 transmission pan that is stock size instead of deep? I've had 3 transmission pans on it and it still leaks. I hope it's not me but it sounds like it. Can you tell me how you would tighten the pan and what gasket you would you for a little help. I've used a stock pan and a chrome pan, both with a drain plug, rubber gasket, installed it and tightened cross wise to 18 inch pounds. I don't know what else to do. Thanks for the help.

[paul2748]

Try a cork gasket. Most of the aluminum pans I've seen are the deep type.


Check on ebay, you never know.

[fordor41]

I never could find a stock depth aluminum pan for our C-4. check sealing surface of the pan. usually the holes are dished from tightening. get the flanges as true as you can. also try a coating of RTV or #2 permatex

['32FordNut]

Thank you Paul and Fordor. I've bought 2 brand new pans so I'm wondering if it might be the transmission casing. I'm going to have to pull it off again now and I'll look at the case to see if there's some imperfection. When I was a kid working at the mechanics shop, we used to use a cork gasket and use Gask-a-Cinch on the pan and gasket, but leave the surface that goes to the case, dry. I might try that. Also a friend of mine said to use FIGP, or something like that. Says you put that on like silicone and then it sets up overnight and is ready for the fluid. Sounds like it's a mess if I need to pull the pan again. I've never not used a gasket and I'm afraid to have all that around the pan. What do you think? Thanks

[Alaska Jim]

are you sure it is the pan gasket leaking? could be that the dipstick tube "o" ring may not be sealing, or the tube may not be all the way on the case. I personally do not care for the rubber gaskets, they always seem to leak for me, and they deform easily if over torqued

[cadillac512]

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Agree about rubber gaskets being leak prone...cork works far better for me. Also, look very carefully at the lever seals on the side of the trans just above the pan. Those things are very prone to leaking.



Terry

[KULTULZ]

- IMO -

Try and find a good quality gasket such as FEL-PRO using a Cellulose/Nitrile composition.

Try to use an OEM pan due to metal gauge. The pan rails have to be straight and you would do that with a hammer and dolly. Be sure some ape hasn't tightened the cap screws so hard as to cause the threads in the case to pull.

DO NOT use any RTV as if the sealant expands into the pan, the lubricant won't like it.

And of course look for all leakages. It might just be fluid blowing back from a forward leak.

[craig]

A common problem on any automatic is if the dipstick is case mounted, the "O" could be leaking, letting the oil drip down onto the pan rail. Also, both C4's and C6's are known for shift shaft seal seepage, same thing, it runs down to the pan rail

[Alaska Jim]

what Cadillac512 said is true. I just finished repairing the c-4 used in my avatar. for a year I thought I had a pan gasket leak. turned out it was a combination of the "o" ring seal on the shift shaft that is kept in place by the kickdown rod was leaking , along with the band adjustment lock nut seal on the drivers side of the transmission. you would be surprised how much can leak out of them. I replaced them, and no more leak, yet I was almost convinced the trans pan was the problem. after I fixed the "o" ring and lock nut there was not even a hint of a leak at the pan. glad I did not waste my time changing it.

[5851a]

Cooler line fittings can also leak, they have an Oring under. Think they are a non-taper thread, as the elbow fittings had a lock nut and straight in ones both had Orings. On the band adjustment nuts, the self locking type, my transmission friend used to wipe a little STP on the rubber seal face before tightening. He said if you didn't the seal would tear a little and leak. He had assembly lube on hand so maybe something to it.

[Alaska Jim]

Yes, you should always use some type of lubricant on "o" rings, and the seal part of the band adjuster lock nut. It will make them "slide" as they are installed, rather than "grind" as they seat

[rotorwrench]

Two types some folks are utilizing are the Farpac and Duraprene type neoprene coated fiber gaskets. If a person uses any form of silicon sealer, it should be used on the pan flange only. The case doesn't tend to warp like the pans do. Straighten the pan as much as it practicable but keep in mind that it will deform as soon as much torque is applied to the bolts. It's just the nature of the beast. Don't fill the pan until the silicon is completely set up if you use it.

If a person uses the neoprene rubber gasket then watch the edge as the pan bolts are being torqued. Stop tightening when you can see the rubber starts to protrude beyond the edge of the pan or case flange. The gasket acts as a locking feature for the bolts due to the constant force of the rubber trying to go back to its original thickness. The rubber will start to extrude if too much force is applied and the gasket will fail.

['32FordNut]

Thank you to all of you who has helped me. I removed the chrome pan I bought and I'm NOT going to use the chrome pan. I looked for the square of the casing, perfect, I looked for the pan on a flat surface, wobbly, I checked the original pan on a table, wobbly. I did order a cork gasket and an aluminum pan from TCI that is only 1 quart larger. So I figured there shouldn't be a problem with it being too deep. I decided NOT to use the FIPG because I have never had luck using silicone products on any pan gaskets and they are a MESS to clean up if you need to remove them. I read the other possibilities where the fluid could be coming from, the "O" ring on the dipstick, very clean and dry, the sides of the tranny with other tubes, fittings, etc, very clean & dry. I think I over torqued the bolts on the chrome one and I should have never used it since it was wobbly when I turned it upside down and checked it on a table (shame on me). Thanks again for all your help, it really helped me on a good checklist. Have a great weekend. Jeff

['32FordNut]

BTW, I've been working on my 1956 Ford F100 and the tranny is bolted up to a old school Mustang 302 engine. I hate leaks. Thanks again for all the help and I'll let you know next week if the new straight pan with a cork gasket works.

['32FordNut]

Ok, here's my update. I bought a TCI aluminum pan. It was really nice until I went to put it on and it had spacers around the lip on some of the holes, but not all of them. Fabricating would have to be done in order to get the brackets mounted. I also was using a CORK gasket instead of the rubber one. I finally banged out the original stock pan, put gask-a-cinch around the pan and one side of the gasket. Installed the gasket on the pan about 10 mins later lining it up to the holes. Turned it upside down and put a little weight on it for about 30 mins. Installed it only torqueing it down to 14 Inch Pounds. Drove it, and no leaks so far. Haven't been out this morning yet. Thank you all for the great advice. I took a little from a lot of you and I think it's going to be a good fix. Thanks again!!

['32FordNut]

I give up. Big puddle on the floor, but this time it's on the drivers side. Something I'm doing. Tranny shop. Can I say
Tranny shop? LOL

[metro1]

My '59 Galaxie leaves a big puddle on the floor after driving. It is coming from the front of the transmission and while driving gets all over. I wiped everything down , started the engine and crawled under the car and watched to see where it was coming from. I was told it's probably the front pump seal.

[5851a]

Gear selector shaft and kickdown rod shaft always would weep a bit but not drip that much. Did blow front pump gasket once. My fault trying to pull to much against wind and rain with foot on floor for couple hundred miles. I cooked it, not too much sealing surface between case and pump in some places. Replaced it on the patio at home, will never do that again. Things they don't tell you is that it can puke all the guts out when you pull it forward. Different than on a bench stand. By God's grace and a little help from Vaseline got it all stuffed back in. Don't want to ever do that again. Find a good transmission man. Everyone is a magician in their field, let them do the magic. I understand body work and I'm nut and bolts type and can-do engines but transmissions and axle I reserve for experts.

['32FordNut]

Metro1, 5851a, thanks for the responses. I've looked that tranny up and down and it is dry except all around the pan gasket, it's soaked. I had the tranny done 2-1/2 years ago and it went back to the shop for the leak. They claimed to have fixed it, but it was still a small leak that would build up after a few weeks. It was my fault for not going back in during the Covid crap and now it's out of warranty. I think 5851a is correct suggesting I just take it to a good tranny shop and have them do it the right way. I've tried 3 times and it's still leaking and it's more than when I started. Thanks for the advise!!

[rotorwrench]

At least you'll have clean oil but that stuff is getting more expensive all the time.

I have an old TH-400 in my brand X elCamino. A dauber wasp made a nest in the vent tube and it would push fluid out around the dip stick tube. Cleared the dead larva out of the vent tube and problem fixed.

I don't have any transmissions that don't mark their spot. Granted, they're just slow seeps but I just get tired of kicking a dead horse so I let them seep. If it's pouring out then that's a different story. I've replaced a few front pump seals in my day. When they go to pouring out when running then a person has no choice.

I used OEM cork gaskets on the rocker boxes of the aircraft engines I maintained for many years but they were replaced every 300-hours. The screws had to be retorqued at every 100 hour inspection since they didn't have a lot of torque on them. Some of the transmission rebuilders use the Duraprene or Farpac type gaskets now days. The Transtar/Transtech overhaul kits come with them. Another type is the Lubelocker type gasket that is metal coated with a material and has silicon bead lines around the bolts and on edges of inner and outer pan flanges. Some manufacturers have gone to a plastic molded gasket with nitrile rubber bead lines similar to the Lubelocker but the gasket is thicker. By all of these changes, folks can see that sealing is a problem with these type pans and flanges and always has been. I don't know if any of them are better than another. A lot of torques for these fasteners are somewhat excessive in my book. If they have a decent locking feature then the torque can be around 75 inch pounds and still work OK. For the foot pounder guys that's a little over 6 Ft/Lbs.

Harley Davidson started making the pan head motors in 1948 and made them well up into the 60s. They had trouble sealing the rocker cover pan so aftermarket manufacturers came up with a thick D-ring that would fit on the outside of the steel pan flange and keep it from being distorted under torque. So far, this has been the best way to deal with the leaks. A cast aluminum pan would be a good idea if it fits well with no gaps or warpage but it needs to be thick enough to take the torque without distortion. It's the distortion that causes the leaks, not the gasket.