Advice Please: '05 4.8is with Trans Fail Safe mode error, have only 50k miles

[crete]

Hello,

I'm original owner driving my 2005 X5 4.8is LeMans Blue off the dealer showroom floor in 2005 with only 11 miles on it. Have had it ever since and only put 50K miles on it, always garaged, all service records. It's my baby and now I have a "trans fail safe mode" error. I read some threads here about this issue, but would like to get some members advice on what route I should take going forward for repairs based on what the issue might be.

I've taken it to my repair shop for over 12 years, originally a Dinan shop, but since has changed owners and former BMW mechanics now run the business. They are very trustworthy and know all about BMWs, but they would send out tranny's for rebuilds. They gave me cost options to decide:

1. Replace solenoid kit only and see if error does not return, if all good, cost 1800.00
2. Go directly to a tranny rebuild (ZF tranny) cost 6300.00 (includes solenoid kit)
3. If I do the solenoid kit only and error returns, may have to rebuild tranny, cost 1800 + 6300 = 8100

I love this car, been my daily driver for work, personal trips and just a great ride. Would hate to lose it, but I'm at a crossroads with repair cost vs age of vehicle. Still in great condition, has custom interior and all top of line options offered for 05 model. I have pics of my baby when I got it 16 years ago, except for some normal wear to interior, in great condition.

My 4.8is Pics

Would appreciate any advice on the path to choose.

Thanks,
Jeff