[KNine]

I managed to cook my D1 300tdi Auto transmission fluid on a recent trip to Morroco, where the red light on the dash would come on when when the engine was working hard going up mountain passes on Tarmac and in 3rd gear.
I had to drain and re-fill 4 times, 4 litres at a time as that is the most that comes out, rest of fluid stays in torque converter. fluid was dark and not bright red.
After 10 days of off-roading at low revs with no problems, Red light came on the next time I was on Tarmac at high revs.
Don't think cooler is blocked as I took it off and was able to blow through.
The thing is, my gearbox dipstick has always poped off ever since I have owned the car, but was wondering if, when it pops off, it reduces the pressure in the gearbox not allowing the pump to operate correctly.
I secured the dipstick with a cable tie and then Managed to drive 900kilomiters home without the light coming on. Does anyone think this was the cause of the problem.
Any advise welcome.

 

[tacr2man]

When you boil a auto it can generate quite a lot of pressure , enough to blow seals out and dump all the fluid , so tying down the dipstick might not be the best idea, when the warning light comes on , the idea is to back off and let it cool down . it might be the temp sensor , is faulty and crying wolf. If you have cooked the fluid it goes very dark and smells burnt , and I would have thought that the friction linings would have been seriously damaged if you had cooked it 4 times . Are you getting the level set right , ie by the correct method, have you checked the flow to the cooler ?

 

[Disco1BFG]

When you boil a auto it can generate quite a lot of pressure , enough to blow seals out and dump all the fluid , so tying down the dipstick might not be the best idea, when the warning light comes on , the idea is to back off and let it cool down . it might be the temp sensor , is faulty and crying wolf. If you have cooked the fluid it goes very dark and smells burnt , and I would have thought that the friction linings would have been seriously damaged if you had cooked it 4 times . Are you getting the level set right , ie by the correct method, have you checked the flow to the cooler ?

Agreed. owners manual contains the preferred cool down procedure - in transfer neutral and drive, with the engine revs held at 2000.

IIRC, sensor closes at 135 degrees C, and this is a bit late for the oil, which is knackered by this point - to get this indication 4 times and still have a functioning autobox would also lead me suspect the sensor - which is easy to change and easy to check - better still fit a gauge. Also - remember that the sensor is on a cooler line, so depending on wether the TC is locked or not, (oil flow reverses on lock up ) might be oil temp in, OR oil temp out of the cooler...

More oil will come out of the box if you leave it draining overnight - especially an older box, with, er, greater "tolerances"! ....

I upgraded my cooler - four times the surface area, and fitted a gauge too.

 

[tacr2man]

Another good move is to go to a full synthetic high performance oil like Redline

 

[KNine]

Agreed. owners manual contains the preferred cool down procedure - in transfer neutral and drive, with the engine revs held at 2000.

IIRC, sensor closes at 135 degrees C, and this is a bit late for the oil, which is knackered by this point - to get this indication 4 times and still have a functioning autobox would also lead me suspect the sensor - which is easy to change and easy to check - better still fit a gauge. Also - remember that the sensor is on a cooler line, so depending on wether the TC is locked or not, (oil flow reverses on lock up ) might be oil temp in, OR oil temp out of the cooler...

More oil will come out of the box if you leave it draining overnight - especially an older box, with, er, greater "tolerances"! ....

I upgraded my cooler - four times the surface area, and fitted a gauge too.

Thanks for the reply, i will have a look at the sensor and definitely see the benifit of upgrading the cooler.

 

[KNine]

Another good move is to go to a full synthetic high performance oil like Redline

Thanks for the reply, I was considering upgrading the fluid and have heard of a product called transon, but not heard of redline, will check it out.

 

[Disco1BFG]

Thanks for the reply, i will have a look at the sensor and definitely see the benifit of upgrading the cooler.

HTH; I got mine from these people:-

alutec. Plant Repair & Radiator Repairs, Manufacturers of hydraulic cooling aluminium heat exchangers, oil coolers, radiators.

their website seems a bit flaky in an old version of Firefox here, but the discovery one is a stock item - the one they made for me should be in the catalogue, as they agreed it was a good idea (!!). I was also told by a certain manufacturer that it is, essentially more or less impossible to over cool the box. PM me for any more info....

gauge is off evilbay - can find the details if you wanted them....

Oil wise, we run Castrol in everything, just sayin

 

[tacr2man]

Thanks for the reply, I was considering upgrading the fluid and have heard of a product called transon, but not heard of redline, will check it out.

Heres a link for info/spec Red Line Synthetic Oil

 

[Datatek]

I managed to cook my D1 300tdi Auto transmission fluid on a recent trip to Morroco, where the red light on the dash would come on when when the engine was working hard going up mountain passes on Tarmac and in 3rd gear.
I had to drain and re-fill 4 times, 4 litres at a time as that is the most that comes out, rest of fluid stays in torque converter. fluid was dark and not bright red.
After 10 days of off-roading at low revs with no problems, Red light came on the next time I was on Tarmac at high revs.
Don't think cooler is blocked as I took it off and was able to blow through.
The thing is, my gearbox dipstick has always poped off ever since I have owned the car, but was wondering if, when it pops off, it reduces the pressure in the gearbox not allowing the pump to operate correctly.
I secured the dipstick with a cable tie and then Managed to drive 900kilomiters home without the light coming on. Does anyone think this was the cause of the problem.
Any advise welcome.

I assume that the gearbox is a ZF4HP22? I would have though it should have a breather pipe, if it's blocked or melted, that would account for the dipstick blowing out.
Personally I'd stick to Dexron but you cannot get all the old oil out unless you use a pressure system so I usually change then change again after a couple of hundred miles, a dose of Lucas Transmission Fix can also be beneficial.

 

[KNine]

Heres a link for info/spec Red Line Synthetic Oil

Thanks for the link, a performance fluid has to be a good option. I suppose I would need to go to a garage and have the old Dextron sucked out to ensure it was fully drained of its 12 litres, before using a new product

 

[KNine]

I assume that the gearbox is a ZF4HP22? I would have though it should have a breather pipe, if it's blocked or melted, that would account for the dipstick blowing out.
Personally I'd stick to Dexron but you cannot get all the old oil out unless you use a pressure system so I usually change then change again after a couple of hundred miles, a dose of Lucas Transmission Fix can also be beneficial.

Thanks, I will need to check the breather to see if that was the cause.
Car works fine at moment in the UK, so will probably start working on it in a few weeks. List of jobs looks like: new dipstick, check breather, change filter and gasket, maybe larger cooler and probably a performance fluid.