My mates 2003 diesel FFR is back in the garage. Following a series of transmission warnings and refusal go go past 3rd gear, the box has been removed again ( taken out last year and 32,000 miles ago after complete failure due to torque convertor breaking up ). Seems this time the gear box oil has been contaminated after coolant got in to it due to a failure in the gearbox oil cooler. Can any one enlighten me as to what has occurred and how you can guard against this .

It appears the gearbox oil cooler has corroded from the coolant side of the heat exchanger allowing engine coolant to mix with the gearbox oil thereby reducing its lubricating properties.
The only way I can think of to avoid it is to replace the oil cooler as a preventive measure. Not sure how you decide when though.
The corrosion could have been partially caused by the coolant not being up to spec by not having been changed for a number of years.
Expensive outcome for the failure of an inexpensive oil cooler.

Normally, the cooler is replaced when the gearbox has been repaired.

Most places wont entertain a warranty claim without a new cooler and pipework...

I replaced mine about 26,000 miles ago ( vehicle has now done 113,000 ) when it appeared to be clogged and was causing transmission probe on ,my 2003 4.4.
At what mileage should you replace this part ?

As Mickey says above... 100% SHOULD have been replaced 1st time around... Was this work carried out by your mate or by a garage/business? If changed by the latter i would A, be going back to them and asking for there explanation & B, consider their lack of knowledge before considering any future work!

We need to change the cooler & pipes & keep proof for our gearbox supplier’s for any future warranty claim! FACT

Something we do agree on Craig

Cam-Tech-Craig wrote:

As Mickey says above... 100% SHOULD have been replaced 1st time around... Was this work carried out by your mate or by a garage/business? If changed by the latter i would A, be going back to them and asking for there explanation & B, consider their lack of knowledge before considering any future work!

We need to change the cooler & pipes & keep proof for our gearbox supplier’s for any future warranty claim! FACT

When I had My gearbox rebuilt the garage insisted that the cooler and radiator where changed, also sounds like it's had the wrong type of antifreeze in the engine, might be a sign of things to come......... Fleabay...... quick  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Thing about wrong anti freeze is that surely rad and heater matrix would also suffer the same failure ?

Err Yes, but the thinnest thing will go first, everything else will follow in time. Do NOT use Methanol based anti freeze, as it reacts with the aluminium and causes it to rapidly corrode. If it's not luminous pink / orange then I would read the label very carefully.

Pink/Orange good

Blue Panic

Green read carefully, no Methanol Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

The BMW 4.4 V8 had blue anti freeze in them from the factory. They had aluminium radiators, oil coolers and blocks. I wouldn't have said it's a reason to panic

Hi Miggit,
The diesel also had blue anti freeze in it from factory.
I changed mine the other month and the coolant that I got from LR is blue.

Ok so Ethylene glycol comes in Blue too, but I think you'll be hard pushed to find Methanol in any other colour, other than the possibility of green.

But there is no escaping that if you put cheap antifreeze in your system, and you haven't checked the content, there is a real risk of doing severe damage to all the cooling system and the engine its' self. Methanol is a cheap and nasty thing and eats aluminum for breakfast, dinner and tea, cos it can  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

So what if a previous owner has used a cheap antifreeze? You may not know about it, is there anyway to tell? 2004 RR 4.4 V8 Autobiography

Presuming it would be the wrong colour Paul... If not then its kind of what you pay for when you have your car serviced Paul, anti freeze gets checked for colour, mixture & level in all device types here...