1986 F250 C6 Torque Converter Drain Plug Location

[Rupert8]

Hello all,

New to Oil Burners - what a find. Great resource. Thanks already for the information I've benefitted from.

1986 F250 XLT Lariat 2wd 6.9: The transmission oil pan was leaking pretty bad so I changed it out. No issues. Since I just bought the truck I didn't know what transmission fluid was in the system so wanted to drain the torque converter.

But I just can't find the torque converter drain plug....

I've scoured Oil Burners and know where it should be. Or so I thought.

Some questions:
*Do all C6 transmissions of this era have a drain plug?
*In the attached photo - is the bolt marked where the socket wrench is inserted the drain plug? (I know it's not right at the bottom, but I couldn't get it there. I started loosening the bolt but had second thoughts and retightened it....). We're looking from the front of the truck to the back in the photo.
*If I can't find a drain bolt/there isn't one, is it the end of the world if I potentially mix transmission fluid types? I'm going to add Mercon V but don't know what is already in there.
*If I can't drain the torque converter, do I just replace the few quarts I removed from the pan (via the dipstick tube) and it will make its way to the pan?

Thanks in advance for the help.

 

[KansasIDI]

Hello all,

New to Oil Burners - what a find. Great resource. Thanks already for the information I've benefitted from.

1986 F250 XLT Lariat 2wd 6.9: The transmission oil pan was leaking pretty bad so I changed it out. No issues. Since I just bought the truck I didn't know what transmission fluid was in the system so wanted to drain the torque converter.

But I just can't find the torque converter drain plug....

I've scoured Oil Burners and know where it should be. Or so I thought.

Some questions:
*Do all C6 transmissions of this era have a drain plug?
*In the attached photo - is the bolt marked where the socket wrench is inserted the drain plug? (I know it's not right at the bottom, but I couldn't get it there. I started loosening the bolt but had second thoughts and retightened it....). We're looking from the front of the truck to the back in the photo.
*If I can't find a drain bolt/there isn't one, is it the end of the world if I potentially mix transmission fluid types? I'm going to add Mercon V.
*If I can't drain the torque converter, do I just replace the few quarts I removed from the pan (via the dipstick tube)?

Thanks in advance for the help.

I am not super knowledgeable on the automatic transmissions, but my understanding is that, with the inspection cover off, rotate the engine by hand with a breaker bar or something until you see the drain plug. Should be between two bolts on the converter. When I helped a buddy with this it was on a 460, they may be entirely different.

 

[Jesus Freak]

I really don't think there's a torque converter drain plug on a C6. And yes, you just fill it up in the dip stick tube.

Edit: it's not the end of the world if you mix a little tranny fluid. I'm of the old school that says that you don't change automatic transmission fluid (I'll receive criticism for that) in my opinion, since you're adding fresh fluid to an old transmission the clutches will start to deteriorate a little quicker. This is how I was taught in auto shop when I built transmissions everyday for two school years.......... and made my shop teachers lots of $$$$ and I got nothing!

 

[Jesus Freak]

I am not super knowledgeable on the automatic transmissions, but my understanding is that, with the inspection cover off, rotate the engine by hand with a breaker bar or something until you see the drain plug. Should be between two bolts on the converter. When I helped a buddy with this it was on a 460, they may be entirely different.

I'd guess you were probably working on an E4OD not a C6.

 

[KansasIDI]

I'd guess you were probably working on an E4OD not a C6.

Could be. I didn’t drive the truck, just helped him flush the tranny. Like said, I’m not super knowledgeable about the autos.

Although that truck was a bullnose, which I thought were C6

 

[Jesus Freak]

Could be. I didn’t drive the truck, just helped him flush the tranny. Like said, I’m not super knowledgeable about the autos.

Although that truck was a bullnose, which I thought were C6

Maybe they do, I can't picture it. And you can do a E40D in a bullnose.

 

[Cubey]

I really don't think there's a torque converter drain plug on a C6.

There is. It's a plug hiding in the small hole above the one with the stud. Draining with it removed. Pic is the old C6 in my RV in 2020.

You must be registered for see images attach

 

[Cubey]

*In the attached photo - is the bolt marked where the socket wrench is inserted the drain plug?

Yes. Look at my comment above this.

 

[Rupert8]

Great, thanks for the information.

Cubey, thank you. Do you mean the area I circled in your photo? Maybe being overcautious but when I began loosening it, nothing drained out....

If so, I'll be pulling it out tomorrow morning and will report back.......

KansasIDI - thanks, but I don't see a drain plug between two bolts, I'm afraid.

Either way, thanks again, all.

Edit: Comparing it to my initial photo, the circled area does seem to correspond. Much appreciated.

 

[gnathv]

When you get the bolt out, rotate it to the bottom to get the most fluid out.

 

[Jesus Freak]

Sweet, the correct answer! Now I know.

 

[Cubey]

Yes, circled is correct. The plug needs to be fully removed to see any drainage, partly loosening won't let any out. Biggest thing is make sure you don't cross thread putting it back.

 

[david85]

For what it's worth, when I rebuild my E4OD a couple years ago, the new billet torque converter didn't come with a drain plug. When I called the shop, he told me the billet front covers don't come predrilled with a drain plug anymore. Most modern fluid changes are done using the cooler lines to "flush" everything out, so maybe the aftermarket considers drain plugs redundant. I wonder if more rebuild parts will omit the drain plugs going forward. In my case, the shop coached me on where and how to drill a drain hole.

The original C6 did have a drain plug though. Same with the original E4OD before I rebuilt it.

 

[Rupert8]

Drilling a drain hole sounds brave....

Thanks for the help, all. Managed to locate and remove the torque converter drain plug thanks to the assistance here. I couldn't fit a socket on with it right at the bottom so kept it to one side in the 4 o'clock position but based on the amount of fluid I had to replace I'm guessing I got the vast majority of it out. Only had time to take the truck for a short run (to my horror it wouldn't engage gears at first until I realised the fluid level was still a couple quarts low...) but on this short drive it seemed to shift just fine after I topped it up. Longer test coming up tomorrow to get it fully up to temperature (which takes forever on these systems) and double-check the fluid level, leaks etc.

Hoping this thread helps others going forwards. Thanks again.