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Is anyone able to confirm what the shop manual states is the proper Torque setting for the DCT TOP Brass Fill plug? After searching, I did find only 1 reference that someone posted back in 2020 but I was hoping others can confirm what it should be..... please !
I'm replacing the brass fill plug with a 6AN Banjo Fitting that will screw into the threaded hole where the brass plug currently is. Attached to the Banjo fitting will be a 6AN fitting with a 2 ft braided hose and another 6AN fitting that I will put a 6AN plug into. It will be mounted to the rear cross bar. For future DCT fluid changes, I will only have to open my easy access ( 1 bolt ) hinged, hatch panel, in the aluminum skid panel underneath, drain the fluid. Put the drain plug back in, and then fill from above in the engine bay !
Is anyone able to confirm what the shop manual states is the proper Torque setting for the DCT TOP Brass Fill plug? After searching, I did find only 1 reference that someone posted back in 2020 but I was hoping others can confirm what it should be..... please !
I'm replacing the brass fill plug with a 6AN Banjo Fitting that will screw into the threaded hole where the brass plug currently is. Attached to the Banjo fitting will be a 6AN fitting with a 2 ft braided hose and another 6AN fitting that I will put a 6AN plug into. It will be mounted to the rear cross bar. For future DCT fluid changes, I will only have to open my easy access ( 1 bolt ) hinged, hatch panel, in the aluminum skid panel underneath, drain the fluid. Put the drain plug back in, and then fill from above in the engine bay !
The banjo bolt is a low grade M12 bolt. Recommended torque on a M12 class 4.6 bolt is 24 ft-lbs. In this case we aren't looking for clamping strength, only compression enough to cause the washers to seal.
^^^ Well, I certainly hope we're not talking about the same thing as I've just received my hardware to make this mod, as well as a set for my buddy....... all based on what another respected forum member stated..... 14mm x 1.5. Guess I'll find out who's correct in a few days. Parts arrived today, but I've ordered a 6mm allen head socket to remove the brass plug easier as well as a box of hose clamps to mount it.
The fill plug we are talking about is the BRASS fitting on the TOP of the DCT..... not the one on the lower side of the DCT from underneath.
Geez......
BTW, that plug is anodized aluminum, not brass. I've replaced one, and it wanted to strip out with steady and increasing force. What worked for me was a T handle Allen wrench and a sharp twist action, came loose straight away. When it breaks free there will be an audible crack sound.
This is the plug on top that I am referring to...... and the description states 14mm thread
GM Genuine Parts Transmission Oil Filler Plug
GM Part # 24299344
Got it. Sorry, 18 ft-lbs for the large aluminum side fill plug. 9 ft-lbs makes sense for the smaller thread size. Kind of an unfortunate poor choice of terminology, since the side fill plug has the identical name of "Transmission Oil Filler Plug". IMO they should have called the brass one the "Transmission Factory Oil Filler Plug" or similar to differentiate it...or the side fill plug the "Transmission Service Oil Filler Plug".
Last edited by Daedalus51; Jun 19, 2025 at 12:20 AM.
This is the plug on top that I am referring to...... and the description states 14mm thread
GM Genuine Parts Transmission Oil Filler Plug
GM Part # 24299344
Yup, and it's anodized aluminum. It's an odd feeling thing when installing too, it gets snug and then gets just a touch easier for a fraction of a second before it feels tight. It's a tiny little plug, I was surprised at how small it is. Because it got easy for a tiny bit, I was initially concerned, when I loosened it to check it, it also did the pop/crack sound as the original one. It's just a bit odd of a plug. Maybe because of the O-ring or the outer edge seating against the aluminum of the case (that's my bet). I put my new one back in with the T handle and not a torque wrench. I use a torque wrench on EVERYTHING, and because it felt like it was starting to strip when removing the original with a ratchet and a hex bit, I just used what worked for removal for installing.
^^^ Thanks Phil. I'm actually NOT replacing the yellow anodized aluminum plug....... I'm putting in a remote DCT Fluid fill set up by using a 6AN Banjo Fitting with a 24" long braided hose that has 6AN fittings on each end and then capping off one end that will be mounted to the rear cross bar using a rubber coated clamp and a standoff spacer. When replacing fluid, I will just uncap the plug, insert a funnel and start pouring in the fluid. No more going underneath for fills......
I already have a hinged access panel for DCT service in the aluminum skid panel ,,,,,,,, so 1 bolt opens the hatch, then just drain the fluid and replace the drain plug, then fill 10 liters from above !
I have a Carbon Fiber Eventuri intake, so I can access the top yellow anodized aluminum fill plug ( formerly called the Brass plug ) without removing the airbox . I just need to remove the clear polycarbonate window and reach in underneath the intake. Hope to be doing this in the next few days......
Sounds good Richard, just remember, the original is sealed by the O-ring and the surface above the sealing area (where a crush washer will hit) isn't a machined surface. It should seal without leaks, but a drop of blue loctite may not be a bad idea, not so it doesn't come loose, but to help seal it. If you use the loctite idea, use some alcohol on a Q-tip in the bore and make sure it's clean and dry.
Thanks Phil........ I'm actually going to TRY and use the O ring, in addition to the crush washer, if it will fit. If not, it will be just the crush washer. Thanks for the idea about some blue loctite.
If memory serves, the head of the original plug actually goes down into the case just a touch. I would test fit your fitting with the O-ring installed and make a call as to use the crush washer or not. My fear would be that since the new fitting isn't going down into the case at all, would the crush washer raise it too much and not enough thread engagement.
Thanks....... I just put the pieces together to see how much threaded area is there with both crush washers in place. I don't have the O ring as it's still in the car on the original top plug. The threaded area remaining from the bottom of the crush washer to the end of the threaded area is 5/8". Couldn't manage to hold it all together along with my scale AND take the picture at the same time. Didn't have enough hands !!!!
I found my original to try and help. You can see there is a bevel to the head and it's a different angle than the hole. You can see on both pictures where the anodizing got ground off when it was tightened into the bore. It looks like from the contact area of the head to the bottom of plug is about 3/8" in length.
DCT top Brass fill plug Torque value?
