98 tahoe t-case

Hello All,
I blew out a ujoint the other day, no biggie. Figure while Ive got the Tahoe up off the ground and its now out of warrenty, Id better do some maintence. Change
diff lube and change the Tcase over to the new blue fluid. Didnt get to the diffs yet. Went to change Tcase though, and NO way was the fill plug coming loose. Ive never seen something so tight. I ended up on it so hard its almost rounded out. Why such a small 1/4 drive plug. Least the diffs are 3/8 drive. Im glad I went to the fill before the drain. Well any ideas, how am I going to get it off now?? It wont take much more pressure before it rounds the rest of the way. My first thought was to JB weld a cheap square bit or extention to it. Who knows Ideas please Help Tony 98 Tahoe z71
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Some PBlaster and a few taps of the hammer. Your turning it CCW ? These usually are not that tuff to get out.
Cheers

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Rokihora wrote:

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Get a Copy of GM Service Bulletin # 99-04-21-001
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"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 1998-99 Chevrolet and GMC K1-2 Suburban, Utility Models
1998-99 Oldsmobile Bravada
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 7--Transmission).
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 20 Nm (15 lb ft).
Parts Information P/N Description Qty
15032997 Plug, Transfer Case Oil Fill 1
Ian
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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~

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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~

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.