123K miles, Control arms, differential.
 

So my mother's 2011 Jaguar is at 123k miles and the right side control arm bushings have worn out.

I'm thinking of replacing both sides, upper and lower, would love some advice for where to buy parts from.
Places I've looked range from $400-700 per upper control arm, and $150-300 per lower. I think these are outrageous prices, yet even a professional indie mechanic quoted me $3500 for the whole job(both upper/lower control arm oem replacement parts+labor).

I'm at a bit of a sticker shock right now, would like to hear some thoughts.
I did some forum searching, and found a guy who did lowers by himself, but doing uppers requires removing shocks, and frankly I just don't have the tools/space for it(NYC, no parking space). I have not found anyone talking about where to buy it from.

2nd issue is I have not replaced the differential fluid, and it's still on factory fluid for 123k miles. I understand that this is not ideal, and with my personal car I change all fluids, even "sealed for life" at their due intervals. This is my mother's car, however, and since the dealer said it's "for life", it's basically for life. -_-
I have the car for the week to repair it, should I bother changing the fluid now, or wait until the diff seizes up and replace(which is another repair price shock incoming)?

What is the proper fluid for the rear diff?

Thank you!

Oh god, you will freak if you price out a rear differential. It will be way more than the cost to buy another used XF. Change it. The dealer fluid is what I use, and it's crazy expensive, but you only need something like .9 liters.

Look on Rock Auto for suspension arm. You'll be pleasantly surprised, and since the rest of the car is about to fall apart with over 120K miles, even the off brands for suspension arms will last long enough.

Oh man, alright, I guess we'll service this differential and hope it's still functional.

Castrol SAF XO 75W90 Is this the proper diff fluid for the car? I went to my dealer in Manhattan and they wouldn't even tell me the specs needed. They kept saying it's "for-life" fluid and basically told me to go away.

Rock auto is my go-to for my daily or the van, I did not want to use that for the Jag.
Their prices are amazing, but these OEM arms have lasted 120k+ miles, so i'm trying to go for OEM again, just not $600 per upper arm.:icon_cry:

Thanks for the reply!

Well, try parts.com, but it's not going to be crazy cheaper.

Yes, it's a Jag, but keep in mind a 2011 XF with that many miles might be worth $7-8K dollars retail. Not a valuable car. And with 123K miles, you probably aren't far from the dreaded timing chain job that will also cost about the amount of the car's value to replace.

Go with the cheap stuff. It will last long enough for this car. It's not a collectible that "deserves" better.

if you dont mind explaining, what are the symptoms of a worn out control arm bushing?

On my previous cars, it caused wandering when driving down straight freeways, and pulling when braking.