Suggestions on the Removal of a Stripped-Out Transfer Case Fill Plug

[DC]

I realize that this is not a question that specifically pertains to a Jeep, but I thought it was related enough to ask it anyway.

Basically, I need to get some suggestions on how to remove a stripped-out NV242 transfer case fill plug.

The quick lube place that has been servicing my 1999 Dodge Dakota pickup for quite some time recently stripped-out the fill plug in my NV242 transfer case. What I mean by stripped-out is not the threads of the plug or the case, but the hex socket itself in the fill plug. The inside corners of the 10mm hex socket have been completely rounded-off so a 10mm hex wrench or 10mm male hex socket just spins around inside the hex socket area of the fill plug. I tried to use my largest extractor which is a #6 (13/32") unit, however, because of the initial smaller diameter taper, the extractor prematurely bottoms-out in the fill plug's shallow hex socket area before the larger diameter portion of the extractor can engage the sides of the rounded-out hex socket walls, so it can't get any bite. I don't have any larger metric or SAE hex wrenches (or larger extractors for that matter), so I am pretty much stuck at this point. I thought of hammering in a chisel into the hex socket, but decided against that as I might end up damaging the threads cut into the softer aluminum case of the transfer case.

Based on all of this, does anyone have any words of wisdom or suggestions as to how I can safely remove the fill plug?

[mrblaine]

Originally Posted by DC

I realize that this is not a question that specifically pertains to a Jeep, but I thought it was related enough to ask it anyway.

Basically, I need to get some suggestions on how to remove a stripped-out NV242 transfer case fill plug.

The quick lube place that has been servicing my 1999 Dodge Dakota pickup for quite some time recently stripped-out the fill plug in my NV242 transfer case. What I mean by stripped-out is not the threads of the plug or the case, but the hex socket itself in the fill plug. The inside corners of the 10mm hex socket have been completely rounded-off so a 10mm hex wrench or 10mm male hex socket just spins around inside the hex socket area of the fill plug. I tried to use my largest extractor which is a #6 (13/32") unit, however, because of the initial smaller diameter taper, the extractor prematurely bottoms-out in the fill plug's shallow hex socket area before the larger diameter portion of the extractor can engage the sides of the rounded-out hex socket walls, so it can't get any bite. I don't have any larger metric or SAE hex wrenches (or larger extractors for that matter), so I am pretty much stuck at this point. I thought of hammering in a chisel into the hex socket, but decided against that as I might end up damaging the threads cut into the softer aluminum case of the transfer case.

Based on all of this, does anyone have any words of wisdom or suggestions as to how I can safely remove the fill plug?

Sacrifice the extractor and keep trimming it shorter until it gets a good bite.

[DC]

Originally Posted by mrblaine

Sacrifice the extractor and keep trimming it shorter until it gets a good bite.

Thanks Blaine. I had actually contemplated doing that, but I guess I was trying to keep away from butchering up a new extractor. But now that you've given me the "OK", that's what I am going to do.

[JLemieux]

Once you have the extractor in place, heat the area around the fill plug. It should come right out.

[DC]

Originally Posted by JLemieux

Once you have the extractor in place, heat the area around the fill plug. It should come right out.

Great ... thanks! I was just about to head out to cut-down my extractor, so I will also heat up the case a bit around the plug with my MAP gas torch and have at it.

[DC]

Man, what a deal. Clearly, the extractor is heat treated & hardened. I first tried to cut it down with a hacksaw and it wouldn't even put a scratch in it. I then used a sharp tool makers triangular file, and got a scratch started, but after using two different hacksaws (one with a brand new high-quality metal cutting blade), they wouldn't even put a dent in it. I then switched to my small diameter cut-off saw with a diamond blade. After two cuts, it basically did the diamond blade in, but I finally got through it.

After heating the case around the fill plug with my MAPP gas torch, I then got the cut-down extractor to bite into the fill plug. I first tried a 12mm open end wrench, but it wasn't long enough, so I couldn't exert enough torque to break the plug free. I then moved up to a 1/2" crows-foot socket with a 3/8" socket wrench, and finally two longer Crescent wrenches, but none of them were able to break the plug free. It's getting pretty cold here now, so I am going to wait until tomorrow to try again with larger (longer) wrenches after I remove the transfer case skid plate which is hampering my getting a more direct purchase on the extractor in the plug.

I may be dreaming, but it almost looks like someone used some form of thread locker on the plug, as it looks and acts like it is literally glued in place. Hopefully I can get it broken free tomorrow.

[TJeeper]

Originally Posted by DC

I may be dreaming, but it almost looks like someone used some form of thread locker on the plug, as it looks and acts like it is literally glued in place.

I had a somewhat similar issue with the 249 in my ZJ. I could not get the plug to move. I tried everything from a breaker bar to an impact wrench (not a good one). I started to round out the internal hex. I took it to my friend's shop for him to try, he got it on the first try with a normal wrench. The reason? I drove it there and warmed up the case. I normally drive a vehicle before changing any fluid, but this time it was raining and I didn't want to climb under a wet vehicle.

[DC]

That's interesting.

I'm still going to try it one more time tomorrow using the extractor with the skid plate off. If that doesn't work, then maybe I'll drive it until it's all warmed up and then try again.

[mrblaine]

I'm guessing that you are using wrenches because the head of the extractor is square? If so, almost every Craftsman tool set I've bought has included sockets that fit square shanks on stuff.

[DC]

Well, I have a ton of tools and the majority are in fact Craftsman, but with all of the SAE & metric socket sets I have (1/4", 3/8", 1/2" & 3/4"), I only have some fairly small 1/4" drive sockets that are square in configuration (but nothing near as large as 1/2" ... which is just a little larger than the square drive end of my #6 extractor). I may be able to jury-rig something up, or perhaps drive some socket over the extractor end, but I know I will have a better go at getting some additional torque on the extractor by taking the transfer case skid plate off tomorrow.

[DC]

OK, I finally got the damn fill plug out of my transfer case. After I got the transfer case skid plate off, I found that a 14mm 12-point socket fit the square end of the #6 extractor quite well and put a breaker bar on it. However, now that I could get some better leverage and torque on the extractor, I ended up just twisting the business end of the extractor in the fill plug, so that was that. I investigated drilling the fill plug, however, due to a welded-in crossmember just behind the rear of the transfer case (anchoring the rear of the two front torsion bars), there was no way to reach from the rear into the fill plug area and even if I could have, it would have been at an awkward angle.

So, I tried grinding some more material off of the tapered front of the extractor, but my Baldor twin-wheel grinder wouldn't even begin to tackle the hardened steel. I then went back to my small cut-off saw, put on a new diamond blade and cut another section off the extractor to get to a larger diameter section of the tool. I then banged the extractor end into the buggered cavity in the fill plug and then heated the hell out of the aluminum areas adjacent to the plug with my MAPP gas torch. I put the socket and breaker bar on the extractor again, but when I started to turn the extractor, it started going off-angle and acting like it was just going to spin inside the fill plug cavity again. Just when I was running out of travel on the breaker bar handle, I heard a loud snap and the plug had obviously broken free! After I completed a bit more with the breaker bar, I switched over to my standard 1/2" ratchet wrench and finished getting the extractor and plug out. Here is a shot of my success:


From the fact that the fill plug was totally flush with the back of the case, and yet the drain plug stood off over 1/8", it is very possible that these same quick lube grease monkeys previously overtightened the fill plug, perhaps using an air impact wrench. Anyway, it's out and I'll get a new plug tomorrow.

Thanks again for the help and suggestions,

Don

[Provelogear]

I bet they didn't change the fluid!

[DC]

Originally Posted by Provelogear

I bet they didn't change the fluid!

I know they didn't, because they couldn't get the fill plug out to begin with. They worked on it for about half an hour and gave up on it (of course stripping-out the fill plug's hex cavity as a "bonus").

[Cutch]

Originally Posted by Provelogear

I bet they didn't change the fluid!

I'm also assumming they didn't take any responsibility for striping the bolt in the first place...

[DC]

Originally Posted by Cutch

I'm also assumming they didn't take any responsibility for striping the bolt in the first place...

I suppose I have to give them some credit for even telling me about it. However, since they have been the only entity servicing my Dakota for the last ~90,000 miles (it has 146,000 miles on it), they have been the only ones touching that transfer case fill plug all during that time when I got regular oil change & lube jobs, so they are the ones that over-torqued it and then damaged it beyond being able to get it back out. I was disappointed when it happened in that they said I would need to take it to an auto repair place to get it out, but no offer was made to pay for that on their part. Anyway, it's out now and once I get a new plug in town later today, I will be telling them that if anyone uses an air impact wrench on the new plug (or otherwise over-torques it), someone is going to lose their head.