94 200tdi automatic discovery overheats gearbox, lights warning light when towing or prolonged uphill driving in warm weather! Is there an uprated oilcooler solution?

 

How long has it been since you serviced the transmission?
Some people do install after market coolers, but I would rather find out what is causing the problem and fix that instead of hiding it with a second cooler.

 

A restriction in flow can do this.
Filter change needed, trans line collapse on the inside.

I have seen a cooler get almost pluged up.

Or a bad temp sensor with a false reading.

I have had pulled a small trailer(500Kg) in 100 plus(40cen) heat at 80mph(150kph) for 960 miles(1600k) stock transcooler and never ran any hotter than normal.
With the AC on.

So you have something thats making it run hot.

Bad fan, fan clutch.

 

Where is the sending unit located for the trans temp? is it inline?

5,000 miles before my SWB tranny failed it triggered the light but it didn't make sense being on when cold, etc...

Is it possible to "clean" lines inside - or is it better to buy a roll of rubber hose and cut into the steel lines? I know it's not as good as steel.

Are there properly sized UNIVERSAL cooling lines (like the u-bend-it brake lines)? That seems to be a better answer than paying major dollar for factory...