Land Rover Repair: Stange behavior on 98 Disco, mobil 1 synthetic atf, fan clutch

Question
John,

I have no idea how many questions you field here, but I recently discussed a possible fan clutch issue and that I had cleaned mine and noticed an improvement in running hot. Whether or not you recall, the weather here in southeast TN has quickly turned from 80/100 degree days to 50/80 degree days and now I'm finding that in the mornings, the transmission is reluctant to shift through the gears when cold. It does not do this at lunch, or at the end of the day, or really any other time. Only first thing in the morning, after sitting for 12-14 hours. As an experiment, I did start it several minutes before I needed to leave one morning and it did much better. I have had this (my second) Discovery since late February, but it did not behave this way in these temps. before. Do I just need to flush and change fluid and filter? I did drain right at 24 oz. the other night, then add a 24 oz. bottle of Lucas tranny fluid, but that offered no improvement. Once warm, I must mention shifts are almost transparent.

Thanks for any advice you may offer,
Michael

Answer
When a car shifts differently cold vs. hot that is a sign that the viscosity of the fluid is changing, which suggests it's time for a change. I suggest you user Mobil 1 synthetic ATF in that truck.  Give it a try and let us know what happens.  To get all the fluid changed you should drain it, refill, and start and run 30 seconds.  Drain that and repeat.  Do that 2-3 times until you drain clean clear red fluid.   That's the only way to swap out all the fluid in the system