Torque converter lock up is random in 4th

**plaven** · 24th May 2015, 09:46 PM

Hi Everyone,

I've become quite aware of 4th not getting TC lock up consistently. IE, I can do the run to hockey, about 20km's at 100kph and TC lock up doesn't kick in. The engine is up to temp, and I'm quite sure the auto should be warm enough.

On of the way home it can take most of the trip back to lock up, or if I'm really lucky it locks up straight away and I cruise home with the revs at about 2200rpm.

I've changed the ATF, the old fluid was really black and smelt a little burnt. I have a filter and gasket here ready to do another change of ATF with the filter change. However I'm wondering if it's worth it.

Given the long running lack of consistent changing up, am I simply better off taking it to a transmission shop to check it out? Is it worth doing the filter and second flush of ATF?

I know this is a bit of a leading question, but who knows, someone might have found general improvement with the new filter and ATF.

The D2 has done 291,000 kms, no idea about the age of the auto though, I'm guessing it's the original.

I'm also thinking of getting a nanocom, would it help in diagnosing issues in the transmission? If so I might wait a bit until it arrives to see if anything shows up.. in the mean time I'll change the filter.

I'm looking to get this car into shape for a long trip from Canberra to Cairns towards the end of year. Given I've had nearly everything in there replaced in the last 12 months, head, all hoses, alternator, radiator (stupidly not the thermostat darn thing stays open, it's fun to watch the temp guage take ages to move and then it's up and down a few times before settling.. winters here in Canberra are COLD - sigh), water pump and some bearing on the front.... I think my last real major concern is the auto.

Thanks.

**discorevy** · 24th May 2015, 11:28 PM

If your thermostat is stuck open as you say then it probably isn't getting up to temp required to lock tc , the gauge will register normal from around 70 degrees, not warm enough . change thermostat , then change your trans oil and filter and clean maf if all good
cheers

**lewy** · 25th May 2015, 06:41 AM

does it lock up in third

**PhilipA** · 25th May 2015, 07:12 AM

As above has pointed out ,TC lockup is dependent on the engine temp being above a set temperature.
It is most likely that the lockup problem is directly caused by the failed thermostat .
I suggest that you replace the thermostat and then observe the lockup, as you should replace it anyway.
Regards Philip A

**plaven** · 25th May 2015, 05:39 PM

Originally Posted by lewy

does it lock up in third

If it's working hard it does.

**plaven** · 25th May 2015, 05:44 PM

Originally Posted by PhilipA

As above has pointed out ,TC lockup is dependent on the engine temp being above a set temperature.
It is most likely that the lockup problem is directly caused by the failed thermostat .
I suggest that you replace the thermostat and then observe the lockup, as you should replace it anyway.
Regards Philip A

On my to do list.

The temp does settle and the gauge sits in the middle.

I have booked it in with a transmission place to do do a check.

**ramblingboy42** · 31st May 2015, 12:39 PM

I think what discorevy said......

I personally wouldn't be questioning the transmission in this case.

if you have an aftermarket water temp guage that shows actual temperature, and everything is up to operating temps and the transmission still isn't locking , then I'd perhaps take it to a transmission specialist......perhaps.....

**ramblingboy42** · 31st May 2015, 12:44 PM

on my td5 the aftermarket guage doesn't show normal operating temps for what seems like ages , and the auto doesn't lock until well into the warm zone.

I wouldn't be concerned about it not locking in 20km trip.

does it lock up when you travel a bit further though?

**roverv8** · 1st June 2015, 06:47 AM

or read these

http://www.aulro.com/afvb/discovery-...r-lock-up.html

**Pippin** · 1st June 2015, 09:35 AM

Originally Posted by ramblingboy42

on my td5 the aftermarket guage doesn't show normal operating temps for what seems like ages , and the auto doesn't lock until well into the warm zone.

I wouldn't be concerned about it not locking in 20km trip.

does it lock up when you travel a bit further though?

My TD5 will lock at 5km even on a cold day, I think not locking for 20km indicates a problem, most likely thermostat as stated before.

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