Transfer case plug stuck!

[wahoo2u]

I need some advice. The fluid check plug on my 99 Tahoe transfer case is frozen stuck and I have messed it up trying to dislodge it. It seems to be aluminum or some other soft metal(Great idea GM engineers). I think I'm going to have to remove the torsion bar mount/crossmember to gain access to drill and EZ-out the plug. Does anyone have similar experience or advice. Thanks for any help.

[Dvldog 8793]

Howdy
Same problem, I was able to get a channel-lock pipe wrench(blue handle similar to a slip joint) on it a get it loose. Also I used a product called PB blaster. It works great with aluminum and has good penitration with other metals also. After that experience I made a 6 point wrench out of a cheap socket and an old wrench.(hard to find a 6 point wrench that size) I cut the socket to fit the nut and then beveled it to match the nut also. This gives me maximum surface contact. I the cut the end off the old wrench and tig welded the socket piece in place. Also since then I've always never-siezed the nut! :D If you do drill it out MAKE SURE YOU FLUSH THE CASE GOOD as metal FOD will get in your case.
Hope this helps!
Conley Janssen

[wahoo2u]

Thanks for the reply,Dvldog. My case is different though.My plug has a recessed square drive. My 1/4" breakover fit pretty good before I rounded it out trying to remove it.And yes, the drilling scares me with the likelyhood of chips falling into the case. Steve

[MTTwister]

Could you dremel the recess out to take a 3/8 or 1/2"? Then PB Blaster the poop outa it, tap lightly to get the blaster down the threads- blast and tap a few more times.

I had a stuck UCA bolt on the Duster - PBBlaster, tourch and tap, work on something else, back and repeat - took me 2 weeks to get that one adjuster bolt to break free.
PB Blaster = good stuff.

[DA BIG ONE]

Be careful if your rig has the NP 246 the case, because it is magnesium and a putting torch to it will likely result in fireworks............

[wahoo2u]

I hadn't thought about the dremel idea. That might work. The main problem is that the torsion bar crossmember is directly behind the case. You can hardly reach the plug to remove it, so I'm sure my first step is to take it out. I've never worked on of these type front ends before so I'm a little leery to start. And yes, it's a magnesium case so the torch is out. I think that's what caused the problem, corrosion between the mag case and aluminum plug. One of GM's better ideas! Thanks for your replies. Steve

[DmaxMaverick]

If you need to put some heat on it, use a heat gun. If you are not familiar with them, they are like a hair dryer, but much hotter. They are used for hobbies and stripping paint. Hardware stores and Walmart have them.

[diesel65]

As per GM service bulletin #99-04-21-001

Some transfer case fill and drain plugs may be difficult to remove. In some cases, the plug may be "rounded out" attempting to remove the plug. These plugs are made of aluminum and have a 1/4 inch square hole designed to receive a 1/4 inch square drive extension.
Installation torque may have been too high causing difficulty in removel.

Caution: To help avoid a fire, thoroughly clean the area around th fill and drain plugs of grease build-up before heating and use only an electric heat gun. DO NOT USE AN OPEN FLAME, If sources other than an electric heat gun are used, the tranfer case may catch fire and cause personal injury.

If the fill and drain plug are damaged during removal and must be replaced, use only aluminum replacement plugs.
Replace the drain and fill plugs (internal square drive tool acess design) with the EXTERNAL HEX DESIGN plug, P/N 15032997.

When you install the transfer case fill or drain plug, tighten plug to 15 lb/ft.

In cases where the plugs cannot be loosened, the use of an electric heat gun maybe make plug removal possible. Heat should be applied to the case around the plug, not directly on the plug, forone to two minutes. Use only enough heat to loosen the plug. Also, fully insert the 1/4 inch drive extension into the plug before turning the plug.

IMPORTANT: Do NOT use plugs made of steel or brass. These may cause a severe corrosive reaction when in contact with the magnesium case, making future removal even more difficult.

[wahoo2u]

Thanks for the advice. I'll see if I can use the heat gun. If that doesn't work, I'm back to taking the tension off the torsion bars and dropping the crossmember.

[DmaxMaverick]

When you do get it out, take the above advice and replace it with the hex plug with the part # given by Diesel65.

Do yourself a favor and use a generous amount of anti-seize going back in. With new magnesium or aluminum threaded parts, it's a good idea to hit them with a light coat of zinc chromate primer. Better yet, if you know anyone with an alodine tank, give it a dip. It will prevent galvanic corrosion and harden the surface, preventing gaulling.

[DA BIG ONE]

Good luck!

As many of you know I had an accident not long ago, and today the insurance company approved a new NP246 case (not a rebuild) for me. Yes, the insurance company wanted me to make a claim against the tow company, but after my breaking their___s they finally gave in.

[moondoggie]

Good Day!

I've never tried it, but in a situation like this I always wondered if, right after heating the case, a shot of quick freeze to the plug might not help. In other words, expand the case, shrink the plug.

I would NOT try this without confirmation by someone who actually knows what they're talking about.

Blessings!

Brian Johnson, #5044

[MTTwister]

Moondoggie - maybe just a touch with an Ice Cube ( frozen water, not the rapper) would do it.

BTW - I wasn't recommending a torch in this case, to this case. Only that I had a B-t-h of a time on the UCA bolt, and heat (alcohol torch actually) was modestly applied with a 5# hammer to get the PB Blaster in there.