98 tahoe t-case

Some PBlaster and a few taps of the hammer. Your turning it CCW ? These usually are not that tuff to get out.

Cheers

I'm gonna ask a dumb question: are you sure that's the fill hole?

My last three GM's all had a large-ish 3/4" bolt for the drain hole and the fill hole. They were both on fairly lightly. Ligher than the engine oil drain plug.

The trucks were '00 and up. Two with autotrack, the new one with AWD.

-marc

Get a Copy of GM Service Bulletin # 99-04-21-001

"WBucha" wrote

I agree with you....here is the Bulletin.

Info - Use of Heat for Difficult to Remove Transfer Case Fill and Drain Plugs #99-04-21-001 - (03/29/1999) Use of Heat for Difficult to Remove Transfer Case Fill and Drain Plugs

with NV136/246 Transfer Case (RPOs NP4, NP8)

This bulletin is being revised to add the 99 model year and part information. Please discard Corporate Bulletin Number 76-74-03 (Section

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 removal.

Caution To help avoid a fire, thoroughly clean the area around the 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 transfer case may catch fire and cause personal injury.

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

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

When you install the transfer case fill or drain plug, tighten the plug to

Parts Information P/N Description Qty

Ian

"Marc Westerlind" wrote

Yeah, it's the fill hole. There were a couple of years that GM made the massive mistake of installing fill and drain plugs that had 1/4" square drives in them. If you didn't have a strong enough 1/4" ratchet or swing handle...you would end up rounding off the plug and make it almost impossible to get the plug out.

Ian

then there's the Rocket Scientist who designed the Warner 1356 with freakin' ALUMINUM fill and drain plugs with a 3/8 drive hole

HINT: those Sears 'Bolt-out' bolt remover tools work on this

Irvin makes an AWESOME took called the bolt-out. It's like an inverse bolt out, but it also works! (as opposed to breaking) I found it invaluable to removing the lug-nuts on my truck, and this may be able to help you.

~KJ~

Well its fully rounded out now. I tried head pb blaster, now Im not sure what to do. Funny thought though, dont they check that fluid level during a normal dealer oil change??? 77k, 2 dozen dealer performed oil changes (last one 2 weeks ago) and it seems like the plug has never even been removed. Is this likely. What should I try now??? What does that service bulliten say? Thanks Tony

Yes. You check fluid with a fill like that by removing the fill plug and seeing if any oil dribbles out, if yes good if not fill it/bad. Hence the easy-to-remove fill plug. Get the bolt-out system from AutoZone and try that. Either that or drill it out - can't let it beat you.

~KJ~