I'm trying to change the transmission fluid in my 2000 manual transmission with some fresh Mercon V. After a couple of hard turns, I was able to loosen the drain plug with a 1/4" socket wrench, but I haven't had any luck at all budging the fill plug. I've tried spraying it with PB Blaster and I've tried taking a hammer to the end of the socket wrench. Nothing has worked yet, so I'm wondering what my next options are.

I have access to an air impact wrench, but I've only used it once. If I were to take this to a shop, is this what they would use to free a stubborn bolt? If so, I'd like to give it a try. I've watched a few videos on YouTube to get my bearings. I know this must sound obvious, but I guess you just apply a little pressure on the wrench to make sure it is snug against whatever you are working on, and then just pull the trigger and let the impact wrench do all the work, right?

Are there any common sense suggestions, like let the wrench work for a minute or two and then give it a rest? Or do you just let it go until the compressor needs to refill?

I'd also like to know if there is a chance that a newbie with an air wrench might make matters worse, like breaking the bolt. Is there a chance that I could cause some damage by letting the wrench work too long on the plug, or is it possible the wrench might strip the plug or snap the plug in two? If that's the case, I'll take it to a local shop before I make matters worse. So far, all I have to show for my efforts are some callouses. But at least I haven't damaged anything except my pride yet

 

Try some HEAT.

 

Try using a 1/2 rachett and smack it with a 2lb hammer. Might take a few hits. If you use a the impact just give it some quick hits forward then back a few times and it should come loose. If you hold the trigger and it's really stuck it could strip the bolt.

 

I think I want to heat the area around the fill plug, and not the plug itself, right? Am I just trying to warm things up to free it loose, like 30 seconds of heat with a propane torch. Or is it more like a minute or two?

 

Thanks Chris. I used a regular hammer, but I was just tapping it. I'll get a 2 lb hammer and put some more force behind it. If that doesn't work, I'll try the impact wrench. Thanks for the suggestion to give the impact wrench just a few clicks at a time. I would have let it run and probably messed things up.

 

I bought my 228K mile 7.3 with a manual transmission in the spring. Immediately after I got it home I swapped out all the fluids to include the transmission, but not how I thought I was going to get it done. So, I drain the transmission fluid out with no problem and put the plug back in. Well, when I went to remove the fill plug I noticed it was not moving at all. PB Blaster, heat from torch, breaker bar, nothing moved the bolt. I think it has never been removed before and has welded itself in place. The 1/4 inch drive hold actually torqued and twisted itself a bit to where I knew it was not coming out.

So, now I had a nice looking 7.3 F-250 with all new fluid in it except for the transmission was dry as a bone. Now what...? I ended doing some research and found out that you can fill the manual transmission from the top through the gear shift lever. I had never seen this done, never heard of it being done, but knew I had to do something. So, I tore into the shift level mechanism and was pleasantly surprised at how easy it was.

Just pull the rubber boot up to expose the level connection and remove the 2 bolts there. Remove the shift level from the shift base. Then lift up on the rubber boot even more to expose 5 or so bolts holding the linkage to the transmission housing. Remove the linkage/lever base from the housing. Now you can see directly into the transmission and pour the required fill amount. I think it was 5 quarts, but I would double check before filling it.

I know you cannot fill it with fluid until it runs out of the fill hole, but this is much better than running it dry... I have had my truck on the road now for a few thousand miles and have seen no adverse effects from filling the transmission this way. I would encourage you to stop messing with the fill bolt and just fill it from the top and move on.

 

Part #5 in the drawing is what you will be removing and then filling the transmission.

 

In the picture below you can just see the lower portion of the shift level attached to the top of the transmission, this again is the part you are removing when you take out the 5 bolts.

 

And finally in this picture you can see the open space that will be left for you to pour the fluid into when you remove the shift lever. You will be kicking yourself when you see how fast and easy this is and after spending so much time with the stuck fill bolt.

 

Thanks Sous. It's good to know there is a Plan B. I wonder if I'm running into the same thing you did. The drain plug took a little effort, but I was able to remove it. By comparison, I can't get the fill plug to budge one bit. I'm going to try again tomorrow with a combination of PB Blaster or LiquidWrench (if I can find it), heat from a heat gun and/or propane torch, and a few smacks to a 2 ft breaker bar with a 3 lb hammer.

I'm a little nervous to work with the torch because this will be my first time using it, so I also bought a heat gun. It looks like the gun will only produce about 1/2 as much heat as the torch, but I thought I'd start there.

How long did you use the torch? I'm also wondering if I should expect it to discolor the transmission. Did that happen when you tried?

Thanks again for the detailed description and illustrations for your ultimate solution. That was smart thinking. I'm glad it got you back on the road!

 

I applied heat via a torch for quite a while to be honest. I probably heated the plug for 5 minutes at a time with a few tries. As I mentioned before, the plug actually started to twist and I can no longer get a 1/4 drive securely in the hole. The fill plug was not coming out, no matter what I did.

I was really surprised at how easy it was to fill from the top and won't even try the fill plug anymore for the rest of the time I own this truck. Keep us posted on what happens and what you ended up getting to work.

 

1/4 drive? Mine accepts a 3/8. Attach a 1/2 to 3/8 reducer to my breaker.

 

Your right, it is 3/8... This is what happens when I reply to posts early in the morning. I was working with my 1/4 drive to remove the door panels in order to replace the actuators last night, so that is where that came from.

As mentioned though, my fill plug has welded itself in place. There is no getting that thing out. I even tried a 4 ft breaker bar and it was not going anywhere. Filled through the top in 15 minutes...

 

We never use impact's on fill plugs, drain plugs, etc.

Heat with a torch and use a long breaker bar. A little shock and it will come out.

I use Sous method of filling because I like to overfill these units 1/2 quart above the fill plug and it's easier if you don't have a pump. Meaning add the 1/2 quart after it starts coming out of the fill plug, screw in fill plug, tighten and add your extra 1/2 quart.