Transfer Case Fill Bolt Stuck – What to Do?

[Dan]

Hi all,

Working on a 2000 Dodge Durango with a nv242 aluminum transfer case. It has 2 bolts for drain and refill. One of the bolt is stuck. Bolt is sitting almost flush with the transfer case which it shouldn’t be. Its a 10 hex mm socket. It should be normally 1/16th or 1/8 above the hole. I have sprayed the bolt with krill oil and let it sit for 15 minutes. I then attempted to crack the bolt with a wrench, then a breaker barn and finally with a dewalt eletric gun. I tried back and forth light impacts with the gun, nothing. I then went to an air gun, same results. Then I put a little heat on the case surrounding the bold with MAP gas. Nothing. The hex hole has slipped once and I have now stopped before it strips.

I have access to oxy/acetylene torch but since the case is aluminum I am afraid that is too much heat. Does anyone have any further ideas on what to try?

Today I got a plastic from a package and using silicone, sealed it the case and then added kroil oil. Not sure this is going to work but figured its really soaking this way.

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• DurangoTransferCaseFluidIMAG1263.jpg

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[David]

I’d stay away from heat, I think – too easy to damage the aluminum housing (while you can heat bolts up so that they are bright red to yellow without much trouble, aluminum is pretty much a liquid at that point…)

Odds are the threads are galled from being overtightened, in which case it may be difficult to get the bolt out with the threads intact (galling can also negate the usefulness of a penetrating oil – the two materials have essentially cold welded together) – you might be stuck using a helicoil or similar after getting the bolt out (thankfully it’s the fill hole. Hopefully you didn’t drain the differential before getting the fill plug off…

I would say the impact is your best option, but an electric probably isn’t going to cut it – you need a good air-driven tool to get it out.

[Dan]

Thanks DrD,

I ended up going to harbor freight and picking up an impact hex bit set and then impacted with my air gun back and forth. It worked! I think the fluid being in there for a few days helped and I was able to get the bolt out. The impact bit is a hair thicker then the regular bit which help snug.

Thanks!

[Author]

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