The ACDELCO filter kit I have included a wadded up ACDELCO pan gasket and a o-ring. Should I use the included pan gasket or the cork gasket I have from Dr. Rebuild? The o-ring looks like it would fit the filler tube. Is it for something else?

Thanks

 

the oring goes on the filter tube

 

O-ring goes on the upper end of the filter tube AFTER you make sure you removed the old one. And if the "wadded up" pan gasket is black and feels like rubber, but looks like cork when you look really close, that would be the one I'd use. The tan cork one is the factory style gasket. They work good, but are not very tolerant of even a little too tight or too loose.

 

If it comes with the synthetic rubber gasket, that would be the one to use....IF you install it properly. That rubber gasket can be reused several times, if not damaged or covered with sealer/adhesive.

The stamped steel sump pan needs to be flattened on the sealing surface. If bolts have been over-torqued in the past, you will have "dimples" around each mounting hole. Those must be flattened and smoothed so there are no bumps or valleys on the sealing face.

Now, use lacquer thinner to wipe off both mounting faces (trans and pan) AND both sides of the gasket. Put gasket on pan and put two bolts in place in the pan at diagonal corners. Put pan/gasket up to trans housing and hand install those two bolts. Now install the rest of the bolts by hand to finger tight.

Use a torque wrench (inch-pound type) to apply 50 in-lbs torque to all the bolts; go around again setting them to 100 in-lbs. Finally, set them all to 150 in-lbs. You should have NO leaks.

 

 

Is this what you speak of??

 

That looks more like a cork or combination (cork/synthetic rubber) gasket. For that to seal over a long period of time, you should follow the same process...EXCEPT....IMO you need to put a thin skin of sealant on both sides of that gasket, first.

I use Permatex Ultra Black RTV: wear latex/synthetic gloves; squeeze a blob of RTV onto fingers and 'rub' it onto both sides of the gasket so there is a very thin 'skin' of sealant all around. It is also important to rub some on the inner edge of the gasket to prevent any possibility of oil passage. In essence, you are creating a "rubber" gasket out of a cork-type gasket. When done, hang the gasket by one of the corner bolt holes and allow to cure before you install it (otherwise, you would NEVER be able to remove the pan!)

P.S. Do not use other types of silicone sealant. Most are not capable of standing up to contact with petroleum products. Permatex-UB is made to seal oil; it's also great to use on end rails for intake manifold sealing.

All of this may seem excessive; but it works. If you plan on keeping this car for many years, you may also want to add a drain plug to the pan. You can get one at NAPA for a few dollars. If you are concerned about ground clearance, you can place it in the rear face of the pan. You won't get ALL the oil out of it, but you will remove most of it so you get no splash when you remove the pan.

 

Thanks 7T1vette

I think I will find the black rubber pan gasket, sounds like it will be better in the long run. As for the drain plug... I'm thinking about going to a cast aluminum pan but I read on CF that the brackets wouldn't fit without some grinding.

Do you know the part# for the speedometer oring? The little oring/washer that fits over the end of the gear in the speedo housing.

 

I don't know the P/N, but you can order an O-ring/seal kit for the gear carrier in your trans from most parts stores or Corvette part vendors.

 

I sourced the speedometer pinion seal from NAPA. They only have 2 part#, 1 for automatics and 1 for manuals.
Would it be beneficial to put this seal on top of the old seal, like the shifter shaft?

 

Nope. Can't do it with that one. BUT, that seal is just pushed into the bore of that speedo 'bullet' {that's what that cartridge is called). You can easily remove it with an icepick or any other small, thin object. Just be aware of how it is oriented so you can push the new one back in the same way.

Also, the other O-ring is easy to remove and replace. Just put a bit of trans oil on both so that they will re-assemble with no problem.

 

Hi 7T1

The 1st pic is the speedo pinion seal I sourced from NAPA. Not the same as what came out but it did fit "snug" in the bore and around the gear.

The second pic is the only black rubber TH400 pan gasket I could find.
It seems pretty thin to me, The cork gasket I have is 3/16".

If I read your post correctly, this black gasket goes on dry??

 

Correct! Gasket 'as-is' with both sides, pan rail and trans rail wiped clean with lacquer thinner. Follow process listed in my prior post to prevent dimpling of pan rail as bolts are tightened.

Good luck!

 

Anyone have a source/part number for stock height dicast aluminum pan for the TH400 that allows the shifter bracket and interlock bracket to be used with NO modifications?