D2 auto transmission reluctant to engage from Park

**Chief Tiff** · 26th June 2022, 04:11 PM

Hi Brains Trust;

The auto transmission on my Disco has this random annoying habit of being reluctant to go into gear from Park; any gear at all. Whether its hot or cold the issue is the same. It started doing it before it's last service (8k ago) so I had the transmission emptied and refilled; the garage said at the time the oil that came out was a bit on the dirty side. Since then the issue still keeps cropping up; I've checked the oil level and it's correct. I've plugged my Nanocom into it and it thinks the car is in whatever gear the lever says it it's in but as far as I'm aware there's no feedback loop telling the system that cogs have actually shifted; just that power has been sent to the solenoids responsible.

The symptoms are very simple; when it plays up putting it into D or R does nothing. I then spend the next 20s to 2 minutes randomly selecting between P and every other gear (with a pause of two marching paces between each movement) until the gearbox suddenly decides it wants to be a team player after all and slips into gear. At which point it behaves normally.... But it's a random thing; some days it never happens, some days I'm having to allow an extra five minutes before each journey to ensure I actually set off on time.

With my very limited knowledge of auto transmissions I'm assuming the issue will be the crap in the solenoid block which will require it to be stripped and cleaned out? If so can anybody recommend a rebuild kit for this? I have no fear of complex hydraulic circuitry and maintaining cleanliness. Or is there a way to carry out a comprehensive flush of the transmission without dropping the valve block? Or could it be something else entirely, diagnosable via Nanocom?

BTW the transmission oil is Penrite ATF FS as recommended on the Penrite website.

Many thanks in advance!

**trout1105** · 26th June 2022, 05:06 PM

How many K's on the gearbox?

**V8Ian** · 26th June 2022, 05:06 PM

Could be the torque converter draining back to the transmission.

**Markf** · 26th June 2022, 05:39 PM

Originally Posted by V8Ian

Could be the torque converter draining back to the transmission.

X2 or the pump delivering low pressure. Probably the seal allowing the TC to drain. Another symptom of the pump failing is intermittent reluctance to actually lockup when solenoid 3 changes state.

**Chief Tiff** · 26th June 2022, 07:41 PM

Originally Posted by trout1105

How many K's on the gearbox?

298,000

Originally Posted by V8Ian

Could be the torque converter draining back to the transmission.

Only 4 and a bit-ish litres of oil drained from the sump; I know because I supplied the garage well over the required amount of fluids and was shocked when they handed nearly half of it back & told me that the 9L listed referred to a complete dry fill and included refilling the TC. If the TC was draining back would that not show up as an overfilled gearbox? Cracking the fill/level plug doesn’t drain any excess and I can’t squeeze in more than an egg-cup full before it comes out again.

Originally Posted by Markf

X2 or the pump delivering low pressure. Probably the seal allowing the TC to drain. Another symptom of the pump failing is intermittent reluctance to actually lockup when solenoid 3 changes state.

Ok; this is a new idea for me; is there any way to check this? BTW; what does solenoid 3 control? Once the transmission engages all gears operate properly and smoothly.

This is all good stuff; what can I do to try and diagnose these problems? If the pump is failing does that require the transmission to be pulled out or can it be swapped out in situ?

Many thanks for these replies guys; I really appreciate it.

**Markf** · 27th June 2022, 12:15 AM

Originally Posted by Chief Tiff

298,000

....

Ok; this is a new idea for me; is there any way to check this? BTW; what does solenoid 3 control? Once the transmission engages all gears operate properly and smoothly.

This is all good stuff; what can I do to try and diagnose these problems? If the pump is failing does that require the transmission to be pulled out or can it be swapped out in situ?

Many thanks for these replies guys; I really appreciate it.

Solenoid 3 controls the lockup clutch. There are three solenoids and the state of the can be seen with a nanocom :-

First gear - 1 OFF, 2 ON, 3 OFF
Second - 1 ON, 2 ON, 3 OFF
Third - 1 ON, 2 OFF, 3 OFF
Third lockup - 1 ON, 2 OFF 3 ON
Fourth - 1 OFF, 2 OFF, 3 OFF
Fourth lockup - 1 OFF, 2 OFF, 3 ON

If the pump is failing you'll see on the nanocom the solenoids changing state with no immediate action from the gearbox. This is especially true of the lockup clutch not engaging when solenoid goes to ON.

If the only problem is that the gearbox fails to immediately engage from Park then in all likelihood the seal keeping the oil in the TC has failed. Replacing that seal or the pump are box out jobs. Cleaning the valve block and changing solenoids can be done in situ.

**Newlandy** · 30th June 2022, 08:11 PM

Are you sure the garage followed the correct procedure for filling the auto box. If the oil level is not correct you may experience the symptoms you have.

**Chief Tiff** · 3rd July 2022, 06:18 PM

Originally Posted by Newlandy

Are you sure the garage followed the correct procedure for filling the auto box. If the oil level is not correct you may experience the symptoms you have.

It’s possible…
This arvo I roped in my Beloved to give me a hand checking the gearbox oil; by getting her to cycle between P, R, N & D I was able to inject another half litre of ATF before it started dribbling out…

Tomorrow I’ll be heading into town and doing “stuff”; lots of starting and stopping so that’ll be a good test.

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