L

Land Ho!

New Member
Hi guys. Earlier today my 2002 4.4 RR started to mess about.
It doesn't want to change up gears?

I pull away and it will change to second once i reach about 4500 rpm but it wont change up to 3rd? Well it will but again, it won't change to 3rd unless i take her upto around 4500 rpm. Which means i have to floor it just to force it to change.

It then stays in 3rd gear. I ran out of road to take her upto speed to see if she would change into 4th once i hit around 4500 rpm like the other gears did. lol

For the last couple of months leading up to this i have been getting an error flash up on the dash saying something like "TRANS BOX NEUTRAL."
It only flashes up with a beep for a split second then goes. I also had the "hi-lo" yeloow triangle symbol flash up on the dash once or twice as well but it always drove fine. Sometimes when i select low range, it wont enable it. However i checked it today after my problems and it let me select low range without a problem.

Is this related? Or just a coincidence?

Also can anyone tell me where the dip stick is for the gearbox so i can check the oil level please? If it has one of course.

Cheers guys.
 
Modern auto boxes don't have dip sticks. You just fill it up through a plug on the side until it runs back out. Checking the fluid is always a good starting point, both the level and the colour, it should be red. If it's black you've got internal problems, assuming that it's been changed as per service advice.
 
dogsbody said:
Modern auto boxes don't have dip sticks. You just fill it up through a plug on the side until it runs back out. Checking the fluid is always a good starting point, both the level and the colour, it should be red. If it's black you've got internal problems, assuming that it's been changed as per service advice.
Click to expand...

Dogsbody, how will i know what the level is then? Im assuming then that if there is oil to the brim when i take the plug off, that that means it's full? Correct?

Cheers
 
Your ZF 5HP24 transmission uses a special fluid called Mobil LT71141 which is amber in colour (looks like thin honey when new). Your transmission doesn’t have a governor.

If you undo the filler/level plug without the engine running around 1 litre of fluid will spill down your sleeve – the engine must be running when you set the level and the fluid temperature must be between 30 & 50 deg.C. (equivalent to about 3 minutes ticking over from cold).

A reluctance to upshift is usually caused by the transmission ECU selecting ‘cooling strategy’ mode because the fluid is overheating. It does this to keep the engine speed high and therefore the pump flow at its maximum. This is generally caused by the bottom eight rows (which supply the water coolant feed to the transmission cooler) of the main radiator becoming blocked with sediment. The radiator can’t be successfully flushed because the bottom hose is above this level and so the radiator must be replaced.
 
Bemble said:
Your ZF 5HP24 transmission uses a special fluid called Mobil LT71141 which is amber in colour (looks like thin honey when new). Your transmission doesn’t have a governor.

If you undo the filler/level plug without the engine running around 1 litre of fluid will spill down your sleeve – the engine must be running when you set the level and the fluid temperature must be between 30 & 50 deg.C. (equivalent to about 3 minutes ticking over from cold).

A reluctance to upshift is usually caused by the transmission ECU selecting ‘cooling strategy’ mode because the fluid is overheating. It does this to keep the engine speed high and therefore the pump flow at its maximum. This is generally caused by the bottom eight rows (which supply the water coolant feed to the transmission cooler) of the main radiator becoming blocked with sediment. The radiator can’t be successfully flushed because the bottom hose is above this level and so the radiator must be replaced.
Click to expand...


Thanks for getting back to me Bemble.
Is there a way of clearing the 8 bottom rows in the rad without replacing it at all?
 
p.s. i've had no coolant in her for a month or 2 now. When i replaced the thermostat, i just filled it up with water. Not sure if that affects what we are talking about. Just thought i'd mention it.
 
I don’t know a way of successfully cleaning all the sediment/corrosion out of those particular rows of the radiator I’m afraid. The radiator isn’t actually that expensive. If you Google part number PCC000850 you should be able to buy a new OEM (i.e. Hella/Behr) unit for less than £200, and they’re easy to fit (slides vertically in & out of a cassette).

Have you seen the TRANS. OVERHEAT message displayed at all?

The suggested test for a radiator blocked in this way is to open the drain tap at the bottom. If coolant pours out then it’s fine. If it drips out then it’s blocked. Problem is, when I tried to open the drain tap on mine it broke off in my hand (due to corrosion).

Other possibilities are the transmission cooler itself, the cooler’s own thermostat (which only allows coolant from the radiator to pass through at ATF temperatures above 80 deg. C) or possibly a faulty transmission fluid temperature sensor - but the radiator is favourite & should be eliminated first.
 
Bemble said:
I don’t know a way of successfully cleaning all the sediment/corrosion out of those particular rows of the radiator I’m afraid. The radiator isn’t actually that expensive. If you Google part number PCC000850 you should be able to buy a new OEM (i.e. Hella/Behr) unit for less than £200, and they’re easy to fit (slides vertically in & out of a cassette).

Have you seen the TRANS. OVERHEAT message displayed at all?

The suggested test for a radiator blocked in this way is to open the drain tap at the bottom. If coolant pours out then it’s fine. If it drips out then it’s blocked. Problem is, when I tried to open the drain tap on mine it broke off in my hand (due to corrosion).

Other possibilities are the transmission cooler itself, the cooler’s own thermostat (which only allows coolant from the radiator to pass through at ATF temperatures above 80 deg. C) or possibly a faulty transmission fluid temperature sensor - but the radiator is favourite & should be eliminated first.
Click to expand...

Hello mate.
No, only the tansbox neutral message has appeared now and then. When it did it meant i couldn't use low range. But most of the time it goes into low range fine.
I'll check the drain tap first and then see what happens when i take off the gearbox oil plug and i'll get back to you.....cheers again.
 
Well i took it round my mates MOT shop to use his ramps....i ended up having to do something else so he looked at it. He un did the drain plug a few turns and black oil driped out. He said the car wasn't running when he did it even though i told him to do it running. He said as i had just driven there it was still hot and would be well circulated?

He said the black oil was my main concen and he didn't bother checking the rad.

He sent me to a local autobox specialist and he said it's most likely the forward clutch?
Im going down there in a minute for him to plug it up to make sure theres no electrical fault. Not sure why im bothering with that though as my All Comms says there are no faults. (i will check again though before i take it to them)

I hope it just needs an oil change!

Just have to see what they say. Will update later today.
 
The fluid may well be black because it has overheated (oxidised). The ‘forward’ clutch as they called it (actually the A clutch) is used in 1st, 2nd, 3rd & 4th gears so, when it fails, the transmission can’t go into its normal limp home mode (i.e. 4th gear) and has no choice other than to clunk into 5th – and you feel it. This doesn’t sound like the problem that you were having.
 
Cheers for the input guys.

I just got a call from the auto box guy.....he said that someone has had the sump off recently for whatever reason......the oil, although a bit browny/black is fine. Could just be where the last owner added different stuff to it......it was slightly over filled.............no elcetrical faults (glad to know my All Comms works)..........he has no idea what it could be.......he thinks it's nothing major whatever it is.....most likely an electrical fault with something else.............changing the oil would not get rid of the problem he said............he didn't check the rad because he said he had never heard of the bottom getting filled with crap etc, however im noing to check that myself later just to be sure.

He mentioned about a lamba sensor fault and how that might be messing things up but i told him that the O2 sensors are fine as i have tested them with an emissions test at my mates MOT shop.

I have no idea what to do now. If i drive for 20 minutes or more i get this problem.
Im starting to fall out of love with this car now :(
 
Last edited:
Land Ho! said:
.......he has no idea what it could be.......he didn't check the rad because he said he had never heard of the bottom getting filled with crap etc, ......
Click to expand...
Sounds like you've found yourself a real expert there :rolleyes:
 

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Bemble said:
Sounds like you've found yourself a real expert there :rolleyes:
Click to expand...

Good find Bemble!
I checked the rad earlier but only visually. When you said it might be blocked at the bottom, i assumed you meant from mud and crap from off roading so i was just looking to see if the fins were caked in crap which it wasn't.
I will try the tap tomorrow. Do you know if i have to take the undertray off to access it? Bottom left isn't it?
 
Bemble, i jsut un done the drain plug on the rad.............at first nothing really came out but the more i un-did it, the more it came out. As did lots of limescae.
When i took the undertray off and did this, i started the car and then noticed that i had a few serious leaks!?

I have never noticed anything before. It seems to only leak when i turn the car on which is probably why i never noticed any leaks before.

Also, is the oil cooler meant to be slightly ****ed? It doesn't look like its level when you look at it. It is also sitting on/touching a hose. The hose isn't supporting the weight of it but i still don't think it should be touching anything else?
Also is there meant oto be any give on it? I can wobble it about somewhat and if i push up on a bunch of hoses, it also moes the oil cooler.
I also noticed that around the filler cap is lots of copper looking flakey stuff? What is it? Rad weld or some awfull crap like it??

Do you recon this leak could be whats causing my gearbox to overheat and do what it does?

Here are some pics. The leaks looks like they were all from the bottom of the rad?

IMG_0655.jpg


IMG_0656.jpg


IMG_0657.jpg


IMG_0661.jpg


IMG_0667.jpg


The hoses im pointing too can be wobbled, thus wobbling the oil cooler.
IMG_0670.jpg

All the grill of the bottom of the rad was soaking and dripping.

IMG_0671.jpg

Notice the drips bottom left ish of the screen

IMG_0666.jpg


IMG_0669.jpg
 
Last edited:
Fitted a new radiator yesterday. Very proud of myself :)
Just need to take it for a long drive to see if it has cured my problem. Fingers crossed.
 
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