ok so just had a complete gearbox drain and refill, new seal, filter, oil change, in my 2001 XJR. On a very hot day at 90.degrees plus sat on M6 traffic jam crawling for miles, about an hour.. then once off the motorway, in normal town traffic my wife noticed smoke coming out from underneath.. I did at the same time sense the gearbox was lagging to change up.. I then carried on but on the way a warning came up “gearbox too hot” and pulled in after a couple of miles into a service station.
I opened the bonnet , to cool her down, looked underneath and drips of ATF on the ground plus it had gone onto the exhaust and cat so that was burning off.
As I was with Footman James RAC I called him and after checking the bolts found one that he could tighten up a bit more by hand. Then topped up with a litre bottle of Halfords ATF (it said was suitable for that model) I don’t have the dipstick so we couldn’t tell how much was required…
After that and a couple more 2 hour journeys she looks dry under there and appears smooth in take up.
I am a bit curious if such a small amount of turn on one bolt could seep that much oil out .
But on an extreme hot condition, is there a safety valve or pressure vent that allows oil to escape?
Or maybe it was so hot, it forced through a slight weep in the seal that just wasn’t tight enough?
Interested to hear if anyone else has had this experience?