Hi All,
I'm new to the site, but am quite interested in getting a RR at some point soon. First question I have is that we would occasionally tow an Ifor horse trailer with a couple of 500kg horses in there. There are a number of nice looking TD6 RR for sale on here at the mo, but i am worried about the gearboxes if using it to tow. Any thoughts/advice on this?

If one of these boxes has already been replaced, are they usually replaced with modded boxes that are less likely to go again, or is it a case of 100K or so out of the recon box and then replace again (perhaps sooner if towing)?

Am currently using either our manual TD5 D2 or the 200tdi defender but fancy changing the D2 for a RR.

Depends on the deal you can get if the car has had the gearbox replaced or not.
If the car has done average mileage then the last of the TD6's will have around 85 - 90,000 miles on the clock. Provided the gearbox has had regular oil and filter changes during its life (Land Rover used to say the gearbox was sealed for life!!), then it is possible for it to do 150,000 miles or even further.
There again it could fail next week.
Buy one with a recent recon box then that will give you some piece of mind. Buy one with its original box, that could be a point to negotiate on price and have something in reserve for when the inevitable happens.
Take our purchase as an example.
120,000 miles but with a duff engine, whilst swapping the engine I had the torque converter reconditioned, changed the oil and filter in the gearbox (also had wrong oil or not genuine oil in the gearbox). No excessive particles were found in the sump of the gearbox at the time, so I left it as it was.
Done some towing, 5 times out with our twin axle caravan since mid April and a couple of favours for a friend by towing a recovery trailer with an old Range Rover on the back each time halfway across the country with no gearbox issues at all.
How long is a piece of string?

Steve. 1968 Series IIA Pastel Green, nearly there project

The main failure mode of the 5L40-E transmission in the TD6 is through reduced hydraulic pressures caused by wear in the valve bodies from spool oscillation in the soft aluminium blocks.

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Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated

I have towed an Ifor with 2 17.2 warmbloods pretty much every couple of weeks for the last 9 years all over the UK. To be honest it is all that it does.

125000 miles and the gearbox hasnt been touched.

Is booked in for a service next week though as I have ridden my luck, pardon the pun.

Best of luck with your search

Thanks. This is really helpful.

Phil, that's a really good explanation, thanks for taking the time to put the pics up.

RRphil real good explanation, my car was chipped on the basis it would prolong the life of the gearbox but 60k later and looks like being changed again and I don't tow only very small trailer to the tip and back. So I believe it's a case of when the gearbox will go and not if.
greg