I'm changing the transfer case fluid for the first time but having a really hard time getting the fill plug out. As you can see from the photos, the space is really tight and there's almost no room for the wrench to turn.

I've looked at DIY Dan's video on how he changed it on his GS, but I'm not sure if the IS has less space compared to the GS because the wrench is not fully sitting over the nut. I tried hammering on the wrench, but the wrench keeps slipping out after a few hits. I'm pausing the hammering for now out of fear that I might strip the nut.

I'm hoping someone have done this on an IS and have some tips to share. I don't know what else to do at this point.


Overview of the fill and drain plugs


Close up of the fill plug

Close up of the 14mm wrench on the fill plug

The direction that the wrench needs to turn

 

I've done this on a 08 IS250 AWD. I feel your pain. It's a matter of luck whether you can get a normal wrench on there and how the bolt is oriented...You can try and come at it from the wheel well.

Some reported getting long wrenched like this that have a small "socket" like design to move the wrench body over enough to not hit the transfer case.

You can either notch/grind your wrench or maybe gently grind the TC to allow more rotation of wrench.

If it were me doing it again, I would buy a cheap wrench and modify it JUST for this job.

 

I've tried the following wrenches from harbor freight and Amazon with no success. Both have very good grip on the nut, but the problem is still with the neck/body of the wrench hitting the TC.

1.https://www.harborfreight.com/8-piec...set-32042.html
2. https://a.co/d/ej9NKPw

I might eventually try grinding down the wrench to give me enough space for it to turn. The idea of coming from the wheel well is also worth considering, but I think that's going to pose a challenge of its own due to not having a direct line of sight to the bolt.

@smitty2919 Thanks for the suggestion.

 

The above tip on the slight socket designed wrench is good. Another thought, if there is sufficient space, is a ratcheting wrench. Something with a high internal pin count (like 72), would maybe allow you to position the wrench better. If you’re having to pound on it, I’d prefer a 6 point wrench head, instead of the 12 you’ve pictured, to prevent rounding the nut head.

 

Ok, you posted before my response, ignore the ratcheting wrench suggestion, you’ve tried it.