Hello friends i have a problem with my GM Transmission from the TD 6 .

On the highway everything ok, with the few more horsepower driving and overtaking is really relaxed, but so 50 km before Munich no adhesion at 200km / h left lane and next to me full of everything, I'm somehow rolled out on the lane, that was not without with the 2.5 to package, everything from 3 min waited and further, then I drove 130-140 km / h, everything was ok, the oil must have become too hot, 1 hour constantly 180-210km / h like that GM gear is not just AMI favorite 80 Miles, a total of almost 1,500 km unwound,

So I think , we need a second oil cooler like this

Click image to enlarge

Before adding extra coolers I would make sure the original coolers are OK....assuming that the cooling is the issue.

The oil cooler is a oil/engine coolant (water) heat exchanger which then uses the bottom few rows of the radiator to cool the water.
The bottom rows of the radiator will get silted up over the years and won't cool the transmission properly.

I replaced the oil cooler AND the radiator when servicing my transmission (I also had a slightly coolant leak so it was a no brainer anyway). I've never had an issue since.

Couple of years ago I had the same problem.
I found this:

Land Rover issued a Technical Service Bulletin in September 2007 for "High Engine Speeds and/or Transmission Shift Problems" which stated :

"The customer may experience high engine speeds and/or transmission shift problems after driving for 25 minutes or longer. There may also be the possibility of the transmission overheat message being displayed on the instrument cluster. High transmission fluid temperatures may be the cause of the problem"

In other words the transmission is selecting 'cooling strategy' mode as the bulk oil temperature has exceeded 140 deg. C.

The fault is caused by a partial blockage in the lower eight tubes of the (engine) radiator which supply coolant to the transmission oil cooler - supposedly caused by "depletion of the coolant corrosion inhibitor".

The bulletin states that it's not possible to clean out the partial blockage and that the radiator must be replaced.

LTB00080 - 15 Aug 2007

VIN Numbers 100042-175505

Gearbox Modes
http://www.fullfatrr.com/forum/topic20319.html

Thank you for the information