The holesaw drilling access point in the trunk worked great for me, although I used a 2.5” holesaw bs the recommendation of 2” . I even accounted for the suggestion by John’s “to the garage” video and slightly altered where I drilled. Again, I have a coupe and can’t speak to any differences to a conv. Removal was easy, 1/2” drive ratchet with extensions and plug was out.
HOWEVER, I will mention that even with a slightly larger hole and slightly moved accordingly from video, a “wobble” type extension provided the best results for removal(harbor freight set, very cheap). For installation of the plug through access hole, I fiddled with it for a while before doing this: I used a retractable (telescopic) mechanics magnet(usually for fishing out dropped bolts or sockets) and set the fill plug on the end, and it took a few tries to get the right angle but once I got it started after a turn or two the magnet just spun on the plug, keeping me from cross threading it. I then used the wobble extension by hand (no ratchet yet) to make sure I wasn’t crossed which was affirmed by a few more effortless turns before feeling resistance. Getting this far, put the ratchet on and tighten good, then keeping extension seated in plug remove ratchet and use torque wrench to proper spec. All set,
your done.

I noticed even with a little bit larger access hole there was a support or component just slightly in the way still keeping me from getting straight on the fill plug, hence the use of the wobble extension which provides a few degrees of deflection. But installing was much harder than removing the plug, and the magnet being such a small diameter shaft allowed me to be more straight on, while also slipping at resistance keeping me from cross threading the plug. It took a few tries but you’ll know by feel at that point. Then using the wobble extension without the ratchet by hand to get a few more turns(whether full or partial) will let you know if you got it or not. If in doubt, pull it out and start again.

if you do an access hole and the threads are already messed up, you’ll have a better chance at using a tap to fix or clean them up. Just go slow, NO POWER TOOLS! Take the plug and wire brush the threads, preferably on a bench grinder with wire wheel or a hand drill with a wheel is best. Then put a couple drops of oil on the threads of plug to ease installation. Good luck!

 

What year car do you have ? I’m a little surprised that with a coupe you couldn’t get the plug off , then back on without drilling an access hole ? Maybe some years of the coupes are built differently than my 2002. IDK. It took me all of 4 minutes for the removal and installation of the plug. Add in 30 minutes to suck out the old lube and put in fresh. Done in under an hour.

Usually I’m not that lucky, so I have no explanation why that maintenance went so smoothly.

Z

 

Well then, there's that done, too.
With the 2004 convertible things are awfully tight back there, but a little patience and a willowy Scandinavian wife with long slender fingers, and we can bid adieu to another on the list of fluid replacement projects. Engine oil, ATF and differential oil done. Brake fluid and antifreeze left to go. There's a weepy lower rad hose to attend to as well. I can hardly wait!🤪
Thanks for all the help with this one. I might have surrendered without all the forum knowledge.

 

I have a 2001 XKR coupe and I changed the differential fluid late last year.
I used a Snap-On ‘SXW 3’ 1/2” drive wobble extension and it worked great.
Yes - the drain plug is tapered. You can actually install the plug by hand if you lay on your back parallel to the axels with your head towards the right rear wheel and reaching up with your right hand.
Someone mentioned that if your differential is leaking at the pinion side then probably the vent is clogged. I need to check that now…


Snap-On SXW 3

 

@zray I have a 97 xk8 coupe. Build date 08/96 lhd American model.
I only drilled the access hole because I read up on it and watched videos, and seemed like a good solution. Full disclosure, I didn’t even attempt to remove the rear differential fill plug by any other means. Maybe I could have, but I didn’t try. By doing the access hole in the trunk I had plenty of
room for installing the hand pump for oil removal and installation. I even bent some sheet metal to make a cover over the hole I made, painted the cover and used sealant and thin foam strips when installing it with a few self tapping screws. Have had no problems with it yet, and I now have an access cover if I want to change oil again

 

sounds like I need to move into the current century and make a video of me changing the rear end lube (in my 2002 USA Model LHD) without using or cutting any access hole (for coupe only.) in 30 minutes or less

Z

 

@zray… I’m sure many members would appreciate and “prophet” from you doing that, possibly myself included. I’ve only put on roughly 1500 mi since the rear diff oil change using royal purple oil, so I have some time before next change, but I would absolutely love to hear any tips for an easier way(as I’m sure other members would too) all help from anyone who’s done it before is priceless info to the rest of us!

Sometimes we bear down and take on a task, using the info we’ve found but in the end encountered things unexpected or not mentioned/explained by those who posted about it, so any extra info is a great help to everyone.

 

I don't know about the coupe but with my 97 xk8 convertible, you only have two alternatives, drill the hole or partly drop the rear subframe .... and that's from someone who has a two-post lift.

Richard