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I pulled the transmission pan on my E40D, 1996 F150 and there was no orange rubber sealing gasket on the old filter. I looked up into where the filter mounts and it looked as though there was already an orange gasket in the mounting hole. Thinking this was to be removed and replaced with the sealing gasket that came with the filter. I find that that gasket is a permanent part of the case and cannot be removed. I reassembled the filter with the associated gasket; it held in place as it was supposed to and installed the pan and fluid. Everything seems to be working normally. My question is what is the deal with the permanent gasket inside the filter mounting hole? For a filter with a longer neck and a deeper pan? Any explanation would be appreciated.
I thought so too but, the upper seal is bonded to the aluminum of the case. I scratched it to see if its removable and I hit aluminum. It's definitely bonded. It seems the filter fit tight and stayed in place using the new seal.
Old rubber goes hard, and is probably hard to remove when your upside down looking up at it.
It comes out, should be taken out.
Aluminum is well, aluminum in color not orange, that is the old gasket.
You run the risk of not having a good seal by having now, two seals, the old and the new.
It is possible that you risk having a leaky seal, and could lose pressure.
The only other thing I can think of is Ford installed a permanent seal/retainer for filters with a longer neck to work with a deeper pan. Napa shows two filters and different pan gaskets. The rubber gasket I used fits the pan with raised holes. The other gasket which came with the filter I used would not work with my pan. Confusing. Also, the filter I didn't use had a longer neck. I wasn't all plastic. It had an aluminum bottom.
2wd got a filter with a short neck, 4wd got long neck, if you have a 4wd and put the short neck on pressure will blow/pop the filter off, and you looze forward/reverse, there was a TSB that they used a retainer that came on the old E40D 4wd to keep it in, sounds like yours has never been changed, and 30 yrs of heat has cooked it in, is why its still in. You can see orange o-ring on them. 2WD short snout
Old rubber goes hard, and is probably hard to remove when your upside down looking up at it.
It comes out, should be taken out.
Aluminum is well, aluminum in color not orange, that is the old gasket.
You run the risk of not having a good seal by having now, two seals, the old and the new.
It is possible that you risk having a leaky seal, and could lose pressure.
You need to listen very carefully to this advice. He's 100% correct. Drop your pan and dig that old o-ring out of there. I can assure you, it will come out.
Last edited by FORDF250HDXLT; Nov 6, 2025 at 03:27 PM.
I'm going to post a couple of photos tomorrow so you all understand better what I'm dealing with. Also, the path of fluid flow is FROM the pan through the filter not from the pump through the filter TO the pan. Correct?
The only other thing I can think of is Ford installed a permanent seal/retainer for filters with a longer neck to work with a deeper pan.
You just made that up. It's wrong. Ford NEVER installed a permanent seal.
The seal stuck up there probably was overheated and is stuck to the pump.
Originally Posted by jcee
I'm going to post a couple of photos tomorrow so you all understand better what I'm dealing with. Also, the path of fluid flow is FROM the pan through the filter not from the pump through the filter TO the pan. Correct?
You're dealing with a removable seal that is stuck to the pump.
And yes, the pump sucks fluid from the pan through the filter.
Then if the pump pulls fluid from the pan, then there's always suction on the filter and cannot be blown off by pressure. And no, I'm not making any of this up.
I took a long ride today and everything worked normally.