limp Wj

[Jaw]

Hey guys

Finally got my WJ rego'd after the injector leak, black death, snapping an injector bolt (replaced it and then it slackened so diesel got in there and it hydrolocked after I tightened it up again!)

And now a new problem. Sigh. haha determined to have her running and hit some mountainbike trails.

So I did around 200 kms since getting her back on the road and the check engine light pops up. It flickers on and off intermittently - more so when cold.

When it's on, the jeep won't shift gears - stays in what I assume is 2nd. Changes gears to park and reverse just fine when it happens.

But it gets strange.

So when I stop or come near a stop, the light pretty much without fail goes off.

When I get up to speed it comes on and won't shift up.

It happened incrementally - it flickered on once on the drive home, two days later it flickered on more when cold and settled down - yesterday it's more persistent but still goes off when stopped and occasionally when driving.

Error codes flag up for transmission electronics.

BUT before I go changing the tranny ECU, the reasons why I'm wondering if I need to:

1) constantly goes 'ok' when stopped
2) occurred incrementally rather than just all of a sudden
3) Car has sat for 18 months indoors. Before this it didn't happen- ever.

SO my questions are:

a) is there any other way to diagnose the problem other than the error codes?
b) I've read that batteries can cause it - It had a small battery in there when the problem started and I read it can be a cause - switched to my Mercedes' battery and took for a 5 min drive where the problem was the same. BUT my positive battery terminal is past its best and not clamping as well as it could - could it be a cause?
c) Trans fluid was changed prior to being laid up. I don't have the dipstick tool so rather than wait for one to arrive, I might dump the fluid and refill - Could low trans fluid cause the problem / result in these issues? I'm thinking that given it occurred progressively, settles down at idle etc etc it could be a case of temps rising when at speed forcing it in to limp mode - plausible?

Just trying to eliminate anything obvious really

[skipperau]

B, possibly but a low likelihood.
C, quite possibly
D, transmission speed sensors are out of whack, giving different readings.


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[Jaw]

Originally Posted by skipperau

B, possibly but a low likelihood.
C, quite possibly
D, transmission speed sensors are out of whack, giving different readings.


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Thanks for that, Digging on C a little more, I fashioned a sump dipstick from some plastic tubing. It looks low - but how high should it be? I've read of people doing it before but am not sure how far up the 'dipstick' the fluid should fall..
Long shot but does anyone have the tool who could measure from the tip of the stick to the low and high points?

Re D: will have a look at that too, thanks, is this a case of resetting? Had the battery out for a short period to no avail

[skipperau]

Originally Posted by Jaw

Thanks for that, Digging on C a little more, I fashioned a sump dipstick from some plastic tubing. It looks low - but how high should it be? I've read of people doing it before but am not sure how far up the 'dipstick' the fluid should fall..

Long shot but does anyone have the tool who could measure from the tip of the stick to the low and high points?



Re D: will have a look at that too, thanks, is this a case of resetting? Had the battery out for a short period to no avail

If you poke the plastic tube all the way in you won’t get a accurate answer unless you borrow someone’s dipstick to measure against as the OEM dipstick doesn’t go all the way in.

Simple answer obviously is buy a new dipstick but I’m guessing you don’t have access to one in the short term at least and are trying to get an answer now rather than later.

From the top of the dipstick tube to the hot high mark is 2’11”, the hot low mark is 2’11 1/2”, the cold high mark is 3’1/2” and the cold low mark is 3’1”.

Re: D, no, if the speed sensors are the issue the only answer is to change them. A fairly easy and cheap job. I would suggest changing both sensors at the same time as they are probably the same age and have therefore experienced the same stress.

[Jaw]

Originally Posted by skipperau

If you poke the plastic tube all the way in you won’t get a accurate answer unless you borrow someone’s dipstick to measure against as the OEM dipstick doesn’t go all the way in.

Simple answer obviously is buy a new dipstick but I’m guessing you don’t have access to one in the short term at least and are trying to get an answer now rather than later.

From the top of the dipstick tube to the hot high mark is 2’11”, the hot low mark is 2’11 1/2”, the cold high mark is 3’1/2” and the cold low mark is 3’1”.

Re: D, no, if the speed sensors are the issue the only answer is to change them. A fairly easy and cheap job. I would suggest changing both sensors at the same time as they are probably the same age and have therefore experienced the same stress.

Thanks for that, I'd imagine it'd take a fair deviation from the low mark to cause an issue? I had a check and I was below the 3'1" - I dropped the oil out and there was approximately 3.8 litres out of what I understand to be a needed 4.7. I poured in about 4.2

It was quite dark too, considering I wouldn't have thought that I had driven more than 1k kms since the last change (albeit 18+ months ago).

Took it for a spin and the light was off - after some time it flickered on once or twice again but was a vast improvement over how it was the other night.

About to take a 50km drive home so will see how she feels after that.

On reflection, it only flickered on at the end of the short trip - maybe the gears took up some of the fluid so it needs a little more.

[skipperau]

Originally Posted by Jaw

Thanks for that, I'd imagine it'd take a fair deviation from the low mark to cause an issue? I had a check and I was below the 3'1" - I dropped the oil out and there was approximately 3.8 litres out of what I understand to be a needed 4.7. I poured in about 4.2



It was quite dark too, considering I wouldn't have thought that I had driven more than 1k kms since the last change (albeit 18+ months ago).



Took it for a spin and the light was off - after some time it flickered on once or twice again but was a vast improvement over how it was the other night.



About to take a 50km drive home so will see how she feels after that.



On reflection, it only flickered on at the end of the short trip - maybe the gears took up some of the fluid so it needs a little more.

No, even fairly small deviation can make them behave oddly, as long as your level is between the high and low marks all will be well.

Yep, always top up after giving it a bit of a run as fluid will fill the pump channels. The fluid will discolour fairly quickly if the level is low as the fluid will get hotter. It changes colour with normal use anyway so you don’t use colour as a guide with these boxes, unlike older boxes using Dexron fluids for example.


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[Jaw]

Originally Posted by skipperau

No, even fairly small deviation can make them behave oddly, as long as your level is between the high and low marks all will be well.

Yep, always top up after giving it a bit of a run as fluid will fill the pump channels. The fluid will discolour fairly quickly if the level is low as the fluid will get hotter. It changes colour with normal use anyway so you don’t use colour as a guide with these boxes, unlike older boxes using Dexron fluids for example.


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Thanks for the feedback I did just that, added around 500ml and drove home and it was spot on, no light and shifted fine - must have been due to the fluid!

I guess two things: 1) I didn't add extra after running it in last time and 2) a litre or so leaked out and a tiny bit extra leaked out in the few kms I did after picking it up.

Will keep an eye on it but she seems happy again