Hi, just a bit of interest for you, my xk8 had a transmission oil change and new pan, filter set as you do after 85,000 miles. car started 'hunting' through the gears and was a real pain to drive.The local main dealer said straight away that it was the torque converter and when would I like it booked in, I thought that this guy must be the best spanner monkey in the world if he can tell what's wrong over the phone so I did some thinking and asked my local machanic to change the oil in the tranny again. this now done the car drives like a dream and it has also fixed the 'kick up the rear end' effect that I was getting after braking hard and accelerating away. I used mobil LT 71141 oil, 6 lts first change, 6lts second change. When the oil was changed for the second time it came out still very dark so it was giving itself a good flush out. never trust a dealer, saved about £3000.00. Good Luck

 

I stay away from a dealer working on any car I have ever owned.

 

Thanks to The Golfer for mentioning that kick up problem. I'm having the same thing in my 99 XK8. The trans filter and fluid was changed sometime ago by the previous owner. I'm going to give it a try and see what happens.
Thanks Again
Mitch

 

If the fluid was still dark at the 2nd drain, it might not be a bad idea to drive it for another month or two, then drain and refill one more time. It really helped smooth out my shifting, as the previous owners apparently never serviced the trans in 81,000 miles. Ensuring that the transmission is topped up completely is extremely important, too, as I have found out. I plan to drain and fill twice more in another 30,000 miles; cheap insurance!

 

Thanks Redline; I had the same thoughts myself. I want to see what the fluid looks like when I drain it.
I just changed the rear end oil. It had never been done in 80,000 mi. It came out jet black. I'm going to drive it for about 3 or 4 thousand and change it again. The shifting seems to have smoothed out. I believe in preventive maintenance. When compared to the cost of doing big repairs because you didn't want to spend the money now makes no sense to me.
Thanks for the advise
Mitch

 

With it dropping out of a higher gear sound like a shifting solenoid is failing . There is a easy meter check for this solenoid at the transmission ECU . Are there any contaminating fluids on the transmission connector on the transmission itself ? Does yours have the ZF5 or ZF6 transmission as the was a point in years they changed over .

A shift solenoid change is a easy DIY item by removing the oil pan only

 

Thanks Lady Penelope for the info. It has the ZF5 Trans. I will check out the things you mentioned.
Again Thanks
Mitch