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Transfer Case Fill Bolt Stuck - Think its Made Of Aluminum How to Get that Bolt Out

7K views 19 replies 10 participants last post by  gc408 
#1 ·
Its been my week for stuck bolts boy.

So I am servicing my NV244 transfer case today. I immediately noticed that 1 of the 2 bolts is almost flush with the case. Its a 10mm hex hole. I am pretty sure the transfer case is aluminum not sure about the bolt. I sprayed some Kroil Penetrating Oil and let it sit there for a good 15 minutes and then attempted to get it off. Tried using my breaker bar and the socket no go. Then tried my impact gun go back and forth slowly, no go. Then I tried my air impact gun a few times, nothing. I tapped the bolt with the side of my mini hammer. Its hard to get a huge swing because the cross member is near by.

Sprayed kroil oil again let it sit then got my mapp torch and heated the outside area surrounding the screw for something like 20 seconds, then got CRC freeze and sprayed the bolt. Hoping to get some shrinkage, but nothing. I tried the air impact gun a few times back and forth nothing. The hex socket managed to start to slip in at least one spot. I really don't want to round the hole.

I am afraid to use MAPP torch for too long because I believe the aluminum casing could melt. I have access to oxy-acetylene torch, thought maybe if I heat the bolt it wouldn't damage the case but that's a huge expensive gamble.

Anyone have any more suggestions on what to try to get this off? :smash:

Generic shot of the transfer case not installed.
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#4 ·
Fill bolt

I've sometimes had success with using a small propane torch and heating the area around the fill bolt, getting it really nice and hot, then applying candle wax to it. Capillary action will draw the wax into the threads (hopefully) and make it easier to remove. It may take several tries but it has worked for me often.
 
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#7 ·
Edit:

It is an ALUMINUM casehalf.

Steel plug (M22x1.5) with a NYLON coating on the threads. These are supposed to be torqued to 17-24ft/pd. Fillplug is (was?) exactly the same.

I would let sleeping dogs lie:
If you can get the FILLplug out; you can use a hand operated suction gun and suck most of the oil out
 
#9 ·
Guys thanks so much for all the replies. So many ideas to think about now. Thanks for that air chisel attachment as well. I just found a page on the web that used it.

Today I got an idea, I took the plastic from some socket I had the one that comes with the cardboard of the product. I then silicones it near the transfer case bolt. Made a small hole on top then let it dry and filled it with kroil oil. My thinking is now the oil will have more time to hopefully penetrate as I drive and the case gets hot. Clearly a dummy over torqued it, no where near 17-24ft/pd.

I want to try the safest option first. In my mind that would be using oxy/ace to heat the bolt. I don't think getting it orange hot is wise. thoughts?

Couple of questions on the suggestions:
1. graham u mentioned heating the boss, you mean the outer circle near the rim or the side of stump that houses the bolt?

2. forty, I know propane is a bit slower then map how long do you roughly think is right? Do you think wax will wick in better then using oil?

3. john, so looks like the plug is steel based on on what autogear uncovered. I just did this plug on my other durango and the screw was nice and shinny. How long should I heat the bolt if I got this route?

4. hcompton, chisel and hammer method. Do you mean just putting the chisel directly into the hole and then hitting it like a nail or are we talking side angle and hammering side ways?

Left hand drill the center of the plug as a last resort, good point a bunch of shavings will go into the case which will suck. But if I am able to drill the center then the screw will be weaker and I should be able to turn it with a hex driver right?

5. autocraft, how did you score those specs? Good knowing screw is steel. wow I didn't know that mag cases existed and were such a fire hazard!

6. lmsport, thanks for the link. How does the bit work? It just hammers straight in?

Ps here is my idea today. Good idea? You guys all came up with good ones and points!

Vehicle Auto part Car Bumper
 
#10 ·
i quess we dont quite understand each others termology so.. heat the aliminium up right around the plug , you do not have to use exsessive amount.aluminium expands more than steel so it should 'release' the plug.however i think the plug is held in by a threadlock/sealer which should release with some heat
 
#12 ·
You're right about one thing, aluminum does expand more than steel. Problem is, when it expands, it expands in all directions including into the threads. Which compresses the situation even more. Heating the plug is best...

Russ
 
#11 · (Edited)
We are in Syracuse NY and were a distributor for New Process from 1946 until after the Magna disaster. My General Manager was an Engineer for New Process for over 20yrs and worked on various transfercase projects. My lead builder was head of their test garage & prototype assembly for over 20 as well. Part of our 4speed redesign seen elsewhere in this forum (thanks to Big Gear Head), was done in conjunction with the guy who designed the synchros for the 833 and an Engineer who worked on the turbo dodge transaxles...

Its egghead central here, sometimes it makes my head hurt LOL

Good luck with your project, I'd still try to get the fillplug out, if you can - use a hand operated suction gun from Harbor Freight and carry on. Thats a pretty thin diecast housing and if you damage it; they're not cheap IF you can find one.
 
#13 ·
The air hammer device has a hex on it that you put a open end wrench on and twist in both directions while hammering, vibration is a beautiful thing, I use my air hammer for many things that I used to have to hit with a big sledge.

Local to me is a guy that does portable welding on automotive problems and repairs, lots of broken exhaust bolts or course, he would use his TIG to build up a rectangle of material on the plug,thereby getting the plug really hot,then let it cool for abut a minute, then spray a mixture of acetone and ATF right at the threads only,then use a modified socket to remove the plug using the rectangle he created. He makes it look easy but he spent 20 years welding missile cases together and is a super-welder.
 
#14 ·
fcastro

Your over thinking this. Use your torch with a rose bud tip, point the flame right in the middle of the plug about 1" away and heat until the plug is a dull red. It should take a 30 seconds. Spray the Kroil on the threads as soon as you remove the heat and wait another 60 seconds then use your impact and buzz it off.
It took me longer to type this then it would take me to remove the plug.

You want to heat the plug.....NOT the surrounding metal. Heating the plug causes it to expand, breaking the corrosion bond, then spraying the Kroil causes the plug to rapidly contract and the Kroil gets drawn in to the threads by the heat and capillary action so it comes out like butter. The whole procedure takes about a minute or longer than it took me to type this.
 
#17 ·
You might be right about the overthinking. I need a pick up the rosebud tip found a #6 on amazon. So I will try this hopefully on Sunday if I can a hold of the tip. My little penetrating oil is still holding quite well. I will first try a light impact and then proceed to try to heat it up till its dull red and spray as you mentioned.

I'll post back, thanks for all the knowledge everyone has provided especially with the helping understand the heating contraction part. Aluminum is not something that you can mess with and fix.
 
#18 ·
Mapp gas or even a propane torch will work. Story:

Couple years ago, my son's Crown Vic started spewing axle grease all over the fender 400 miles from home. At the time, we were hoping it was just an axle seal and pulled into a Petro stop on I-10 to get some fluid added. They pi$$ed around with it for an hour and couldn't get the fill plug out. We left the car there, swapped our luggage into their car, they rode home with us, then went back later and got the car with a U-Haul trailer. I heated the plug for a few minutes with a cheapy hand-held propane torch, stuck a socket extension in, gave a couple raps with a 2# hammer, and it backed right out. Turned out the axle bearing was munching the axle, good thing he didn't try and drive it! I've had visions of that axle breaking coming over the Mississippi River bridge in Baton Rouge...

Russ
 
#19 ·
Just wanted to update. So after driving the car around for a few days with the penetration oil covering the bolt I decided to give it another try.

I went to harbor freight and picked up some a long hex impact socket set. I figured that the tools would have a little more thickness because of the coating which should help with the slipping. I then took my impact and went back and forth a few times finally after about 5 times I felt the bolt give and then it was cake work.

Just wanted to update. So after driving the car around for a few days with the penetration oil covering the bolt I decided to give it another try.

I went to harbor freight and picked up some a long hex impact socket set. I figured that the tools would have a little more thickness because of the coating which should help with the slipping. I then took my impact and went back and forth a few times finally after about 5 times I felt the bolt give and then it was cake work.

 
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