Auto-box oil cooler.

On Saturday I was towing at full weight to a Steam Rally which took me via an alternative route to avoid a 1 in 4 hill. The route I took had a long nasty 1 in 6 hill on it, and nearly at the top, I could smell the engine and box getting warm and then noticed a warning light come on as I reached the top which I assumed was the auto box warning. I knew there was a long 2 mile downhill through a cool wooded area over the brow to let the motor cool down on the decent.
As soon as the load eased on the box, the light went out and I was able to carry on to the rally.
I did keep an eye on the water temp gauge at all times and it stayed absolutely spot on, so I know it wasn't the engine overheating.
Is there an oil cooler that can be fitted to help the auto box when towing?

Just to add, I came back in the evening with the same load when the air temp was a lot higher (25degrees), and had no problems.

johnboy6 said:

On Saturday I was towing at full weight to a Steam Rally which took me via an alternative route to avoid a 1 in 4 hill. The route I took had a long nasty 1 in 6 hill on it, and nearly at the top, I could smell the engine and box getting warm and then noticed a warning light come on as I reached the top which I assumed was the auto box warning. I knew there was a long 2 mile downhill through a cool wooded area over the brow to let the motor cool down on the decent.
As soon as the load eased on the box, the light went out and I was able to carry on to the rally.
I did keep an eye on the water temp gauge at all times and it stayed absolutely spot on, so I know it wasn't the engine overheating.
Is there an oil cooler that can be fitted to help the auto box when towing?

Just to add, I came back in the evening with the same load when the air temp was a lot higher (25degrees), and had no problems.

Click to expand...

There are a number of things you could try to avoid overheating the 'box:

1. Did you keep the 'box in "D", or were you using the gears?


Dave

I always use the gears when towing to give the box more of a chance. In hindsight, I maybe should have dropped into the low box and just let her take her time, but with it being the alternative route I thought she would cope in high range, I shall know in future.

Ok that's great.

Are you aware that on TD5 auto has Torque Converter lock-up in both 3rd and 4th?

As you know the heat is created when the TC is in open mode acting a bit like a slipping clutch, once it's in lock-up mode it produces a lot less heat.

For that reason alone when I'm towing a fair amount of weight, 2-3tons, I don't bother using "D" at all and just run in "3" with lock-up.

Dave

Cheers Dave, I was not aware of the lock-up in 3/4 gears. I was in 1st high all the way up the climb.
John.

johnboy6 said:

Cheers Dave, I was not aware of the lock-up in 3/4 gears. I was in 1st high all the way up the climb.
John.

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Hi John, next time you are towing try using 3rd, it goes into lock-up about about 45mph.

If you were having to use 1st it does sound as though something is not quite right.

Have you tried any of the following:

1. Towing with the air filter removed?

2. Have you cleaned the MAP and MAF?

3. Have you checked that all the turbo hoses are intact, externally as well as internally?

4. Have you tried towing with the MAF disconnected?


Dave

Will try what you have suggested Dave and see what happens.

johnboy6 said:

Will try what you have suggested Dave and see what happens.

Click to expand...

Well there's no harm in trying. Just another quick thought for you.

If towing and general low speed hauling is import to you, you might consider changing the TC for a modified one, allow me to explain:

As you are aware in an auto box there is this component called a Torque Converter and in simple terms it acts a bit like a clutch in a manual car - just automatically.

This means that until the TC locks-up, there is always a certain amount of power loss. Now this TC in the Land Rover has what is called a "Stall speed" of 2600 to 2800 revs, which in theory means that you shouldn't get loads of revs spilling over the top a bit a like those Daf infinitely variable auto boxes of the 70's and 80's, with their inherent loss of drive.

However, theory is one thing but the reality is something else. In my opinion they fitted the wrong TC unit - they should have fitted the same unit that goes in with the V8 engines which has a much lower stall speed, so should give more 'direct drive' feel.

Apparently I was not the only one who thought this as Ashcroft Transmissions have now developed a modified TC based on the v8 unit and with a stronger drive plate.

Having driven one of these modified TD5's I can tell you it completely transform the driving experience overall.

1. No more revs spilling out with no drive - get to approx 2000rpms and you get direct drive, so the TC works less hard, produces less heat and more drive;

2. TC lock-up works much more precisely and at lower speeds;

3. Towing was improved immeasurably - on the test I was towing a trailer grossing 2500 up long motorway in 3rd lock-up almost like it wasn't there.


If I were still needing to use TD5 auto this would be my first mod.

Cheers
Dave

thebiglad said:

Well there's no harm in trying. Just another quick thought for you.

If towing and general low speed hauling is import to you, you might consider changing the TC for a modified one, allow me to explain:

As you are aware in an auto box there is this component called a Torque Converter and in simple terms it acts a bit like a clutch in a manual car - just automatically.

This means that until the TC locks-up, there is always a certain amount of power loss. Now this TC in the Land Rover has what is called a "Stall speed" of 2600 to 2800 revs, which in theory means that you shouldn't get loads of revs spilling over the top a bit a like those Daf infinitely variable auto boxes of the 70's and 80's, with their inherent loss of drive.

However, theory is one thing but the reality is something else. In my opinion they fitted the wrong TC unit - they should have fitted the same unit that goes in with the V8 engines which has a much lower stall speed, so should give more 'direct drive' feel.

Apparently I was not the only one who thought this as Ashcroft Transmissions have now developed a modified TC based on the v8 unit and with a stronger drive plate.

Having driven one of these modified TD5's I can tell you it completely transform the driving experience overall.

1. No more revs spilling out with no drive - get to approx 2000rpms and you get direct drive, so the TC works less hard, produces less heat and more drive;

2. TC lock-up works much more precisely and at lower speeds;

3. Towing was improved immeasurably - on the test I was towing a trailer grossing 2500 up long motorway in 3rd lock-up almost like it wasn't there.


If I were still needing to use TD5 auto this would be my first mod.

Cheers
Dave

Click to expand...

Thanks for the info Dave. It is certainly worth looking into.
The general weight I tow is approx. 2.5 tonnes plus the trailer which puts me up to approx.3.5 tonnes gross.

johnboy6 said:

On Saturday I was towing at full weight to a Steam Rally which took me via an alternative route to avoid a 1 in 4 hill. The route I took had a long nasty 1 in 6 hill on it, and nearly at the top, I could smell the engine and box getting warm and then noticed a warning light come on as I reached the top which I assumed was the auto box warning. I knew there was a long 2 mile downhill through a cool wooded area over the brow to let the motor cool down on the decent.
As soon as the load eased on the box, the light went out and I was able to carry on to the rally.
I did keep an eye on the water temp gauge at all times and it stayed absolutely spot on, so I know it wasn't the engine overheating.
Is there an oil cooler that can be fitted to help the auto box when towing?

Just to add, I came back in the evening with the same load when the air temp was a lot higher (25degrees), and had no problems.

Click to expand...

It seems as though no one answered your question. I believe there is already an at oil cooler on these discos. So shouldnt need one. One thing to do though is check the gearbox fluid level. If its running low then there is less thermal capacity.

Steve.

StallionSteve said:

It seems as though no one answered your question. I believe there is already an at oil cooler on these discos. So shouldnt need one. One thing to do though is check the gearbox fluid level. If its running low then there is less thermal capacity.

Steve.

Click to expand...

Tks for the input Steve, I will get it checked in the morning.

John.

johnboy6 said:

Tks for the input Steve, I will get it checked in the morning.

John.

Click to expand...

checking the oil is not particulary straight foward to do, but check the web/manual i cant quite remember the process...

Steve

Checking the oil level on the TD5 autobox is quite straightforward, you just need to follow this procedure:

1. As there is no dipstick for the autobox oil level, you need to get underneath, locate the oil level/fill plug and slacken it , but DO NOT remove at this stage. This plug is normally of the allen key or Torx style and is found on the front face of the gearbox sump;

2. Once that plug has been slackened, start the engine and cycle through each autobox position on the selector pausing to allow drive take-up before moving onto the next position. Once you have gone through P N R D 3 2 1 and back to P, LEAVE THE ENGINE RUNNING;

3. Now get back under the vehicle and with a suitable receptacle in place to catch any oil, remove the level fill plug. You may find a small trickle of oil comes out - that is the correct level - you may find no oil comes out, so it needs topping up with some ATF (Auto Trans Fluid) Dexron III, until a small trickle starts to come back out - then replace the the level/fill plug and secure.


Now you know the level is correct; if you have not done an autobox oil change since owning the vehicle, you may consider doing it now.

Details of this procedure are available on request.

Cheers
Dave

Thankyou all for the wealth of info you have given me. I will let you know how I get on.