Diff and transfer bolts stuck

Trying to change all my diff fluid and not a single bolt will budge. Any tips would be appreciated

 

Put the socket in place then hit it hard with a hammer a few times first

 

Try spraying them with PB Blaster or equivalent. Wait a few minutes and then place the correct-sized socket (6pt) on the bolt/plug and give it a few firm hits on the end of the socket with a small hammer. Don't beat on them or over-do it. Let sit five minutes and try removing the plug. If it doesn't want to budge, move on and repeat the steps on each. If you are doing all three unit's, by the time you spray and tap on them all and get back to the first, it will be time to try moving them. If not: repeat the spray and the tapping. One or two repeats will usually do it.

Remember to verify all of the the fill plug(s) will come off before touching the drain plugs, or you'll end up having a real bad day.

 

Use a shallow 6-point socket and a longer breaker bar. A good impact wrench works as well. On my 2010 4Runner I had to use my Milwaukee mid-torque, rated for 550 ft-lb.

 

@Williston I used your technique with fluid film and it finally work. Took about 4 rotations on each but they finally gave way. Thanks for the help!!

 

Nice! Glad it worked! I saw a video on the web by a local mechanic and did mine using that technique. He pointed out that it was especially important with the front diff plugs with those hex head bolts that can strip out so easily trying to remove them. I remember he made sure the hex on them was cleaned/wire-brushed well, and used the spray and tap method with I think a dedicated hex socket of the correct size. He spent extra time on them making sure it was fully seated and tight in the bolt. It came out almost as easily as the others.

 

This. I had to use the 6 points and 1/2" breaker to get my front diff forsaken hex plugs off. Replaced them with the Lexus 6 point plugs. And yes, fill plug off first, always!

 

Do you guys prefer impact or ratchet on rusty bolts?

 

Don't force it, get a bigger hammer!

 

I know this isn’t the answer you are looking for…….


But it depends on the bolt.
And where the bolt is located.

 

yeah I get that. It’s always a gamble. I broke 3-4 skid plate bolts so now I’m shook.

I feel like every bolt I take out is going to break. The truck isn’t even really rusty. It’s probably 9/10 condition

 

Impact is the least amount of work. However, if the bolt is long and slender, or if the location requires extensions, there will be enough flex that the impact forces won't be transferred sufficiently to the threaded joint. At that point use a breaker bar, not a ratchet.

The exception is if you think either the bolt will break or the weld nut inside the frame/body will break. In that case use heat and loosen with a ratchet. The sway bar bracket bolts are known for this. In my 4Runner, I've also encountered it with running board brackets and rear bumpstop brackets.