Little background first:

when i purchased my td5 auto it was cheap, but in overall good condition. as a result of the price there were a few jobs that needed doing.

one of which was the oil cooler for the AT box, at some point in the past the AT box cooler had failed and been replaced with what i can only describe as a postage stamp sized cooler from fleabay costing no more than £5 with a couple of quid postage..

not ideal. The oil lines had been cut on the stainless pipe about 2 inches from the gearbox and then rubber hydraulic hose jubilee clipped onto it which meant i was filling up oil every 500 miles as it would get low due to the drips.

As a temporary fix i invested in a (permanent) 19 row oil cooler with AN10 fittings and mounted this to the right of the AC fan and piped in with SAE J20R3 heater hose with an ID of 5/8ths and clamped it hard down onto the remaining steel lines, running up the side and over the top of the engine out the front to the new neatly placed oil cooler.

this seems to have sorted several problems, the box is smoother now it's not getting so hot in normal operation and i no longer have a small puddle of ATF under the landrover wherever i stop, imaintain that this was beneficial as it was constantly changing oil, but unfortunately the significant other decided she didnt want a red puddle outside the house.

however it is far from ideal, as J20R3 is not rated for ATF at all (whilst it maintains some oil resistance its not perfect) and i only considered it a temporary measure.

Now.. i have been supplied with a set of cooler pipes with all but the small rubber bit at the end present, which i dont need.

my intention is to get a proper set of hydraulic hose made up and attached appropriately to the steel lines, but i have a few questions. i will also be doing a full box service as per various websites instructions around the internet and replacing the filter.



1: The fittings on the cooler are -AN10 (suitable for 5/8ths hose), and the pipe will likely have an an8 fitting on it, (1/2inch). Failing being able to get a suitable fitting to take the 5/8ths hose would a steel reducer (5/8ths to 1/2) be suitable for joining the different sizes of hose?

i.e. https://www.ebay.co.uk/itm/232610246749

2. are there any other considerations i should be aware of before i do a full flush and refil of the box?

3. is there any benefit to using dextron 3, or is DII id suitable

For question 2: According to my knowledge you will not be able to do a full flush on your auto box without having special equipment. Some old oil will remain in the box (20-30%). This is why it is recommended to do the oil change 2 times (2nd one after about 100kms).
In the past I also had an automatic D2 with with issues changing from one to two, which has gone after the 2nd oil change.

the amount of new oil that has gone in it it's almost had two complete full changes as it is (well, as much as will come out when you undo the cooler pipes), i refilled with just shy of 8 litres the first time.

I do not remember how much I could fill in one time, but according to the manual the full qty is 9.7 L from dry. So if you could refill with 8 liters means that almost 20% remained in from old oil.
But the 2nd change is only a recommendation and maybe one should also be fine. I have done the 2nd time as well because I still had the change problem.

Toseland said:

my intention is to get a proper set of hydraulic hose made up and attached appropriately to the steel lines, but i have a few questions. i will also be doing a full box service as per various websites instructions around the internet and replacing the filter.

1: The fittings on the cooler are -AN10 (suitable for 5/8ths hose), and the pipe will likely have an an8 fitting on it, (1/2inch). Failing being able to get a suitable fitting to take the 5/8ths hose would a steel reducer (5/8ths to 1/2) be suitable for joining the different sizes of hose?

Click to expand...

Go to your local hydraulics place with your bundle of parts and measurements for pipes and get them to make it all up for you.

I recently had a 3/8 braided stainless teflon lined remote sender pipe for my oil pressure gauge made for £18 including a load of other fittings, ferrules & unions.



You could most likely get feed and return lines done in 5/8 braided with what ever fittings or adaptors that you need and then it is simply a case of clipping them up into place.