D4 2.7 Transmission Warning

[gavinwibrow]

I suspect the answer is "Protection", but I'll ask the question anyway.
If I tow my block of flats with my 2.7L 6 speed without using cruise control, I can't ever recall the transmission warning coming on.
However sometimes with cruise on, usually at a reasonable speed and then suddenly having a hill to mount, the warning will come on and the transmission revert to 4th gear. I then have to stop and switch off to revert to normal.
Comments from the wise?

[Tombie]

When was the last time you had the transmission serviced?

Do you have a Gap IID, I’d suggest monitoring transmission temps for a while.

[gavinwibrow]

When was the last time you had the transmission serviced?

Do you have a Gap IID, I’d suggest monitoring transmission temps for a while.

Transmission was serviced 25K ago before starting a 21K touring "northern AU in winter" trip (trans rebuilt about 100K km prior), and again on our return 3 months later. Did the warning thing a couple of times on the trip whilst in cruise at about 80-85 kmph when then climbing a mild hill after many km of flat (I don't use cruise in anything but flattish travel).

Then did the warning again today en route to Perth along the flat coast from down south.

Monitored with GAP for the full trip, with a separate thread elsewhere on here (including ATF temps - max 134C from memory and usually building slowly to a bit below that most days).
Block of flats is 3.2m high and just under 3.5T, so living almost on the edge towing, but 100% better outcome that the sometimes struggling D2 before that. Not that its necessarily any recommendation, but I do hold a HC licence (for almost 50 years now), and was a professional driver for a few years.

[CanadianRyan]

I suspect the answer is "Protection", but I'll ask the question anyway.
If I tow my block of flats with my 2.7L 6 speed without using cruise control, I can't ever recall the transmission warning coming on.
However sometimes with cruise on, usually at a reasonable speed and then suddenly having a hill to mount, the warning will come on and the transmission revert to 4th gear. I then have to stop and switch off to revert to normal.
Comments from the wise?

Mine does the same, although it's only when towing my camper trailer up hill, often when overtaking a large truck etc. The code it throws is P0741-00. I've got 170k on mine and trans has been serviced 3 times... speaking with mechanic he thinks it could be heat related but I'll have it inspected at the next vehicle service. I'm hoping there's a cheaper solution than a full trans rebuild.

[DazzaTD5]

Gav you should take a snap shot of fault or send me the info, at your leisure.
I don't think its a big drama, over the years this has come up a few times with people towing.
I believe there are others that have looked into this in quiet a lot of detail with regards to it being a land rover fault rather than something going wrong.

We shall just keep the service up on it and truck along [smilebigeye]

[gavinwibrow]

Mine does the same, although it's only when towing my camper trailer up hill, often when overtaking a large truck etc. The code it throws is P0741-00. I've got 170k on mine and trans has been serviced 3 times... speaking with mechanic he thinks it could be heat related but I'll have it inspected at the next vehicle service. I'm hoping there's a cheaper solution than a full trans rebuild.


Yours has the same format as mine, and I too very much suspect its just a LR caution thing, rather than anything to specifically worry about. But of course, as always, I'll do as Dazza requests.

[scarry]

That code came up in mine while working hard in low range.

Turned the car off and on,and it was fine,then reset the fault code using GAP tool,and it has never appeared again.

[gavinwibrow]

That code came up in mine while working hard in low range.

Turned the car off and on,and it was fine,then reset the fault code using GAP tool,and it has never appeared again.



Time to do a bit more real driving?

[matti4556]

I suspect the answer is "Protection", but I'll ask the question anyway.
..... I can't ever recall the transmission warning coming on.
However sometimes with cruise on, usually at a reasonable speed and then suddenly having a hill to mount, the warning will come on and the transmission revert to 4th gear. I then have to stop and switch off to revert to normal.
Comments from the wise?

Gavin what does the "message centre" warning actually say?
I look at the descriptions in the workshop manual and is has 4 options...
1. Transmission fault limited gears available
2. Transmission fault and overheat
3. Transmission fault
4. Transmission overheat

The P0741-00 code mentioned is listed as "Torque converter clutch permanently open".

The fault strategy is as follows...
Default (Limp Home) Mode
If a transmission fault is detected by the TCM, the TCM adopts a limp home mode strategy. 'TRANS. FAILSAFE' is
displayed in the message centre and, if the fault has an effect on engine emissions, the MIL will also be illuminated.
In default mode, P, R and N functions operate normally (if the fault allows these selections) and the TCM locks the
transmission in 3rd or 5th gear to allow the driver to take the vehicle to the nearest dealer. The torque converter lock-up
clutch is disabled and reverse lock-out will not function.
If the vehicle is stopped and subsequently restarted in the default mode condition, the TCM operates normally until the
fault which caused the condition is detected again.
When limp home mode is active, the gear position indicator will show one of the following letters which defines the fault
type:
􀁺 'F' - transmission is operating in limp home mode
􀁺 'H' - transmission has reached overheat threshold temperature and transmission is operating in limp home mode
􀁺 'E' - CAN bus is off and transmission is operating in limp home mode.
If electrical power is lost and the transmission is operating in mechanical limp home mode, the selector lever will not be
locked in the 'N' position by the shift interlock solenoid. The lever will be locked in the 'P' position and can only be
released by using the interlock emergency release lever or by correcting the electrical fault.

And you mentioned temperatures, then the following is the strategy for overheat (above 137°C)

Cooling Strategy
The purpose of the cooling strategy is to reduce engine and transmission temperatures during high load conditions, when
towing a trailer for example. Under these conditions the engine and transmission may generate excessive heat.
If the transmission fluid temperature increases to 125ºC (257ºF) or higher, the TCM employs the cooling strategy. The
message 'TRANSMISSION OVERHEAT' is displayed in the message center.
The strategy uses a specific shift and torque converter lock-up clutch map. This map allows torque converter clutch lockup
and gear shifts to operate outside of their normal operation. This will reduce the engine speed and/or slip in the torque
converter, therefore reducing heat generated by the engine and the transmission.
If the transmission fluid temperature increases to 137ºC (278ºF) or higher, the transmission will use the default (limp
home mode). 'H' is displayed in the gear position indicator. If the temperature exceeds 140ºC (284ºF), CAN bus
transmission is disabled and 'E' is displayed in the gear position indicator.
The cooling strategy is cancelled when the transmission fluid temperature decreases to less than 120ºC (248ºF) or below.

I am keen to hear what the outcome is as I recently had my box and TC overhauled for slip and overtemp. I was towing my 3T van up the gateway bridge in Brisbane (a long climb with the loud pedal pressed a bit further than normal) and was concerned about my sudden lack of power. It was actually locked in 4th gear limp home because of the detected slip. Stopped for a coffee break further on and the fault cleared when re-started. Happened again nearer to home, again uphill taking off from lights. Slipped in 3rd and loss of power - didn't know enough about it at the time to look at what gear the old girl was using now. So she had a 10th birthday present - rebuilt box and TC. Don't judge me. the old girl deserved it [smilebigeye]
My money is on overtemp (TC cause?) or detected slip in possibly 4th or 5th when coming to hills. Did you get the torque converter overhauled when the tranny was done?
I hope the above helps with understanding the tranny a bit more. and yes - keep driving it until it becomes a real issue because, as you already know, its not a cheap fix at this time.
Cheers - Matti.

[gavinwibrow]

Many thanks Matti. Comprehensive response much appreciated.

Mine would have been a lower end overheat resulting in reverting to 4th gear on each occasion ie at about 134C trans oil temp. I never got any of the other instrument panel warnings (older 2.7 screen?).
Don't know if T/C was rebuilt along with auto trans but will ask PO if I can get hold of him.

Now that I know about it, it will probably never occur again for me to take a snapshot for Indie DazzaTD5.



Gavin what does the "message centre" warning actually say?
I look at the descriptions in the workshop manual and is has 4 options...
1. Transmission fault limited gears available
2. Transmission fault and overheat
3. Transmission fault
4. Transmission overheat

The P0741-00 code mentioned is listed as "Torque converter clutch permanently open".

The fault strategy is as follows...
Default (Limp Home) Mode
If a transmission fault is detected by the TCM, the TCM adopts a limp home mode strategy. 'TRANS. FAILSAFE' is
displayed in the message centre and, if the fault has an effect on engine emissions, the MIL will also be illuminated.
In default mode, P, R and N functions operate normally (if the fault allows these selections) and the TCM locks the
transmission in 3rd or 5th gear to allow the driver to take the vehicle to the nearest dealer. The torque converter lock-up
clutch is disabled and reverse lock-out will not function.
If the vehicle is stopped and subsequently restarted in the default mode condition, the TCM operates normally until the
fault which caused the condition is detected again.
When limp home mode is active, the gear position indicator will show one of the following letters which defines the fault
type:
􀁺 'F' - transmission is operating in limp home mode
􀁺 'H' - transmission has reached overheat threshold temperature and transmission is operating in limp home mode
􀁺 'E' - CAN bus is off and transmission is operating in limp home mode.
If electrical power is lost and the transmission is operating in mechanical limp home mode, the selector lever will not be
locked in the 'N' position by the shift interlock solenoid. The lever will be locked in the 'P' position and can only be
released by using the interlock emergency release lever or by correcting the electrical fault.

And you mentioned temperatures, then the following is the strategy for overheat (above 137°C)

Cooling Strategy
The purpose of the cooling strategy is to reduce engine and transmission temperatures during high load conditions, when
towing a trailer for example. Under these conditions the engine and transmission may generate excessive heat.
If the transmission fluid temperature increases to 125ºC (257ºF) or higher, the TCM employs the cooling strategy. The
message 'TRANSMISSION OVERHEAT' is displayed in the message center.
The strategy uses a specific shift and torque converter lock-up clutch map. This map allows torque converter clutch lockup
and gear shifts to operate outside of their normal operation. This will reduce the engine speed and/or slip in the torque
converter, therefore reducing heat generated by the engine and the transmission.
If the transmission fluid temperature increases to 137ºC (278ºF) or higher, the transmission will use the default (limp
home mode). 'H' is displayed in the gear position indicator. If the temperature exceeds 140ºC (284ºF), CAN bus
transmission is disabled and 'E' is displayed in the gear position indicator.
The cooling strategy is cancelled when the transmission fluid temperature decreases to less than 120ºC (248ºF) or below.

I am keen to hear what the outcome is as I recently had my box and TC overhauled for slip and overtemp. I was towing my 3T van up the gateway bridge in Brisbane (a long climb with the loud pedal pressed a bit further than normal) and was concerned about my sudden lack of power. It was actually locked in 4th gear limp home because of the detected slip. Stopped for a coffee break further on and the fault cleared when re-started. Happened again nearer to home, again uphill taking off from lights. Slipped in 3rd and loss of power - didn't know enough about it at the time to look at what gear the old girl was using now. So she had a 10th birthday present - rebuilt box and TC. Don't judge me. the old girl deserved it [smilebigeye]
My money is on overtemp (TC cause?) or detected slip in possibly 4th or 5th when coming to hills. Did you get the torque converter overhauled when the tranny was done?
I hope the above helps with understanding the tranny a bit more. and yes - keep driving it until it becomes a real issue because, as you already know, its not a cheap fix at this time.
Cheers - Matti.

[DazzaTD5]

but will ask PO if I can get hold of him.



I still have a chuckle at this. Isnt the previous owner sick of you yet? You do realise people sell a vehicle to have it out of their life for whatever reason, not to have a new relationship with the next owner. A bit like still socialising with an ex partner, hey some people do it no issue. [tonguewink][tonguewink]

BTW I've not seen your old Disco come back for servicing, he may have found a new mechanic for his new vehicle.

[DiscoJeffster]

I still have a chuckle at this. Isnt the previous owner sick of you yet? You do realise people sell a vehicle to have it out of their life for whatever reason, not to have a new relationship with the next owner. A bit like still socialising with an ex partner, hey some people do it no issue. [tonguewink][tonguewink]

BTW I've not seen your old Disco come back for servicing, he may have found a new mechanic for his new vehicle.

Lol.
Watches car leave the driveway -
“Blocks number”
“Marks email as junk”

Good riddins!

[gavinwibrow]

I still have a chuckle at this. Isnt the previous owner sick of you yet? You do realise people sell a vehicle to have it out of their life for whatever reason, not to have a new relationship with the next owner. A bit like still socialising with an ex partner, hey some people do it no issue. [tonguewink][tonguewink]

BTW I've not seen your old Disco come back for servicing, he may have found a new mechanic for his new vehicle.


Probably. Chuckle on, but he has already kindly replied to a number of queries, remembering that in this case he didn't WANT to sell, he needed to for personal reasons.

[gavinwibrow]

Just a wee update which may or may not be relevant.

On the last towing trip back from Kalbarri to Perth, I had about 4 instances of the previous transmission fault (had not read faults until now and was saving them to show Dazza in 10 days time).

This time I was looking at a different instrument mode option in the GAP tool, and noted that each fault was immediately preceded by "Current Engine Torque" exceeding 400 Nm - remembering that we are considering a 2.7L, not a 3.0 TD or SD, so my simple brain suspects that it is a built in LR over-ride, even though my remap gives me an increase to 500 Nm.

Plus, having just now read the faults on my GAP tool, there are no faults, so each engine switch off then resume must have excised any faults?

[Eric SDV6SE]

Gav,

Most DTC's are stored indefinitely until physically cleared or fault fixed or both. I understand the GAP tool has settings to show you only new ones.

[DiscoJeffster]

Gav,

Most DTC's are stored indefinitely until physically cleared or fault fixed or both. I understand the GAP tool has settings to show you only new ones.

Acknowledged are, pending aren’t as I understand it. Pending will go after time if the fault doesn’t reoccur enough to become acknowledged.

Pending are also hidden by default on the IID which trips up most people chasing down Restricted Performance errors which take time to acknowledge.