Transmission Pan Leaking

Kisner · 01-14-2001, 12:06 AM

I have a 68 coupe, 302 4V, with C4 transmission. My problem is I can't stop the transmission pan from leaking. Have tried both cork and rubber gaskets, and even replaced the pan. I've looked everywhere and see no signs of the leak dripping from somewhere else. Been fighting this for months. Any ideas anyone?

Clark Rodgers · 01-14-2001, 01:46 AM

Kisner,
Hopefully you have used some type of sealer with these gaskets and have you looked at the pan real close to see if it is warped?

If that checks out, look at the seal where the shifter arm goes into the trans. had one leak there once and I swore it was the gasket.

------------------
69 351W Sportsroof deluxe

Michelle Page · 01-14-2001, 02:13 AM

Have you checked the grommet where the dipstick tube goes into the case?

------------------
1995 Mustang V6,automaatic
1966 Mustang
The long term project
1983 Mustang GT
The 460 project

Gearhead999 · 01-14-2001, 08:15 AM

Yes, check the dipstick tube "O" ring. Also, check the seal where the linkage goes through the case. One more, check the band adjuster nuts. You usually ruin the seal they make if you adjust the band.

tomhyl1 · 01-16-2001, 07:28 PM

Had the same problem with my 71. Kept on finding puddles, yet no change in trans level. found a brake line leaking by filler res. finding its way down on top of tranning. Hope this helps

71 Mach 1 351C, project car.

Kisner · 01-20-2001, 06:33 PM

Mr. Rodgers,
You mentioned using a sealer. Do you mean RTV. The instructions that came with the gaskets, along with everyone I've talked to, said to definitely not use RTV. Do you recommend I use a real light coat of it. Still can't find any other evidence of a leak.

Gearhead999 · 01-20-2001, 11:50 PM

Don't use RTV. It will cause more harm than good.

[This message has been edited by Gearhead999 (edited 01-21-2001).]

Clark Rodgers · 01-22-2001, 11:28 AM

Kisner,
I know that RTV in the transmission is bad news but I do not use a putty knife when I use it. Use a brush and apply a thin amount on the gasket and apply it from the bolt holes to the outer edge and this will keep the sealer out.
If you don't feel good about this change the pan.

------------------
69 351W Sportsroof deluxe

Kisner · 02-02-2001, 02:08 AM

After several months of thinking it was my transmission pan leaking, I finally located the leaks. It's leaking from one of the band adjuster nuts and also the modulator. Can't tighten the band adjuster nut any tighter - any ideas how to stop that leak. For the modulator, my biggest problem is it's not the original transmission and I have no idea what type or year car it came out of. The part # is on the side of it. The modulator AutoZone has for a 68 doesn't resemble mine. The one on it has two ports coming out the side - one to the engine and for a small vent hose. Would one of the ones with one port work?

01-14-2001, 12:06 AM	#1
Kisner Registered Member Join Date: Nov 2000 Posts: 290	Transmission Pan Leaking I have a 68 coupe, 302 4V, with C4 transmission. My problem is I can't stop the transmission pan from leaking. Have tried both cork and rubber gaskets, and even replaced the pan. I've looked everywhere and see no signs of the leak dripping from somewhere else. Been fighting this for months. Any ideas anyone?

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01-14-2001, 01:46 AM	#2
Clark Rodgers Registered Member Join Date: May 1999 Location: Rowlett,Texas Posts: 306	Kisner, Hopefully you have used some type of sealer with these gaskets and have you looked at the pan real close to see if it is warped? If that checks out, look at the seal where the shifter arm goes into the trans. had one leak there once and I swore it was the gasket. ------------------ 69 351W Sportsroof deluxe

01-14-2001, 02:13 AM	#3
Michelle Page Registered Member Join Date: Nov 2000 Location: Kingsport, TN Posts: 102	Have you checked the grommet where the dipstick tube goes into the case? ------------------ 1995 Mustang V6,automaatic 1966 Mustang The long term project 1983 Mustang GT The 460 project

01-14-2001, 08:15 AM	#4
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	Yes, check the dipstick tube "O" ring. Also, check the seal where the linkage goes through the case. One more, check the band adjuster nuts. You usually ruin the seal they make if you adjust the band.

01-16-2001, 07:28 PM	#5
tomhyl1 Registered Member Join Date: Dec 2000 Location: Santa Ana, CA USA Posts: 4	Had the same problem with my 71. Kept on finding puddles, yet no change in trans level. found a brake line leaking by filler res. finding its way down on top of tranning. Hope this helps 71 Mach 1 351C, project car.

01-20-2001, 06:33 PM	#6
Kisner Registered Member Join Date: Nov 2000 Posts: 290	Mr. Rodgers, You mentioned using a sealer. Do you mean RTV. The instructions that came with the gaskets, along with everyone I've talked to, said to definitely not use RTV. Do you recommend I use a real light coat of it. Still can't find any other evidence of a leak.

01-20-2001, 11:50 PM	#7
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	Don't use RTV. It will cause more harm than good. [This message has been edited by Gearhead999 (edited 01-21-2001).]

01-22-2001, 11:28 AM	#8
Clark Rodgers Registered Member Join Date: May 1999 Location: Rowlett,Texas Posts: 306	Kisner, I know that RTV in the transmission is bad news but I do not use a putty knife when I use it. Use a brush and apply a thin amount on the gasket and apply it from the bolt holes to the outer edge and this will keep the sealer out. If you don't feel good about this change the pan. ------------------ 69 351W Sportsroof deluxe

02-02-2001, 02:08 AM	#9
Kisner Registered Member Join Date: Nov 2000 Posts: 290	After several months of thinking it was my transmission pan leaking, I finally located the leaks. It's leaking from one of the band adjuster nuts and also the modulator. Can't tighten the band adjuster nut any tighter - any ideas how to stop that leak. For the modulator, my biggest problem is it's not the original transmission and I have no idea what type or year car it came out of. The part # is on the side of it. The modulator AutoZone has for a 68 doesn't resemble mine. The one on it has two ports coming out the side - one to the engine and for a small vent hose. Would one of the ones with one port work?