I have an '06 LR3 with 190,000 miles. Everything is working right now and I do not want to induce any problems messing around with it. That being said, I want to perform any maintenance required. I am going to change the spark plugs. I would like any suggestions as to what else I should do. I also just purchased the GAP IID tool so I have that to work with.

 

if you havent done them yet, drain and put fresh fluid in the front diff, transfer case and rear diff. 75w/90 gear oil in the diffs and Royal Purple Synchromax in the t-case is the typical choice. (assuming you do not have an HD with the electronic rear diff, thats a different animal)

fill volumes are:

front diff = 0.6 qts
transfer case = 1.5 qts
rear diff = 1.1 qts (for open diff)

all in all shouldnt take you more than 1-2 hours. you will need a set of torx sockets for the plugs.

word of advice on the transfer case, do not try to muscle the plugs loose or over tighten. The case is aluminum with no steel sleeves for the plugs, doesnt take much to strip the threads

 

Also make sure you can open the fill plug before you drain