TF-80SC Geartronic Transmission Solenoid Overhaul

[Curtius]

Thought I'd add a few notes/observations having just completed this job on a 2007 XC70 geartronic transmission. It had been suffering from the well documented 2 to 3 flare, changedown bumping on coming to rest and horrendous bang into reverse when the transmission fluid was warm. Had considered a number of options - replace transmission with another second hand one, replace valve body, replace solenoids individually at a decreasing overall cost i.e. £500 upwards plus fitting for a gearbox, £460 for a replacement valve body or £260 for a set of solenoids. As one who enjoys a challenge/project I decided to try the cheapskate option of overhauling the solenoids myself. Using various forumite's write ups and 'bunnybr's YouTube video at https:/youtu.be/0nh0rp7HSrw I removed the cover from the valve body, extracted the solenoids and opened them up by carefully making a number of hacksaw cuts in the end of the casing to allow removal of the end cap and solenoid armature. I then cleaned out the bushes inside the solenoid coil with a 4mm reamer and re-assembled the whole unit. I did not dis-assemble hydraulic spool valves which seemed to be fine. I completed the work with a 'Gibbons' flush and installation of a magnefine filter in the fluid cooler return line. This seems to have completely cured my problems at the cost of a reamer (£7), a new valve body gasket (£9), Magnefine filter (£30) and a 20 litre drum of Mannol JWS 3309 transmission fluid (£65) result!

For those contemplating a similar exercise here are a few observations:
1. Remove all the stuff on top of the transmission - air box etc. to ease access.
2. Remove large diameter pipe between the intercooler and engine inlet manifold.
3. Undo radiator bottom hose, drain the coolant and move pipe to one side.
4. I undid the four subframe bolts and dropped the subframe by about 30 mm at the front as recommended but am not sure this is necessary as the important thing is to raise the engine relative to the subframe (with a block of wood on a hydraulic jack under the gearbox).
5. Ensure all torx head bolts are removed before trying to remove the valve cover! After I had done this the cover came off relatively easily and with a bit of wriggling was removed upwards.
6. The most difficult task because of the confined space you are working in was to remove the solenoid connectors. As others have detailed, a small screwdriver to lever the connector open whilst levering the female connector off did the trick.
7. The solenoids slide out smoothly after the locating pins have been removed with a magnet.
8. Take a number of pictures of the solenoid orientation and harness support brackets to enable correct re-assembly of these items. With my phone I was unable to get a picture of the whole valve body assembly due to not being able to get the phone far enough away so took a number of pics of the different areas.
9. I disassembled all six solenoids to be on the safe side although my symptoms pointed to only the C3 solenoid (middle one on the right) sticking.

If you experience similar symptoms my advice would be to 'have a go' as the work is not particularly difficult as long as you are double jointed!