3rd Gear Lock. Gearbox Error

[VR4WGN]

:baby: hi guys well the car is up and running,but iv noticed it locks itself in 3rd gear and flashes slow N signal light,iv toppd fluid up and car is in air and i drive,when it reaches 3rd after a while it locks,i want this car fixed and gone i ned the room lol,plese may you guys help me,please please

[Louis]

Thats safe mode, (any gearbox probs and it will do that) it may be a sensor, there are three of them on the box, check they are all plugged in etc, cheers Louis

[Atik]

Thats safe mode, (any gearbox probs and it will do that) it may be a sensor, there are three of them on the box, check they are all plugged in etc, cheers Louis
Is that what I've seen referred to as 'limp home mode'?

Didnt know the gearbox did that...

[ritch_w]

the oil could be cooked too, would harm doing a flush and ATF oil change (with AMSOIL).

[VR4WGN]

the oil could be cooked too, would harm doing a flush and ATF oil change (with AMSOIL).
its brand new oil in it,i draind it and put new oil in it,so i dont see how it could be tht,could i use speed sensors off any box? i have some i pulled from a few wrecks but cant member wich 1 was from wich tho,any other probs it could be?

[elnevio]

its brand new oil in it,i draind it and put new oil in it,so i dont see how it could be tht,could i use speed sensors off any box? i have some i pulled from a few wrecks but cant member wich 1 was from wich tho,any other probs it could be?
Hmmm - which atf did you use? Amsoil or Mitsi's own DiaQueen SPIII? Or something else?

[Kieran]

Hmmm. It's a bugger trying to diagnose one of these boxes without getting the codes out of it.

Problem is without being able to 'Plug in' you're guessing. When it locks in 3rd, does the 'N' light flash about once a second? If it does, that does narrow things down a bit to one of these, according to the workshop manual:

Input shaft speed sensor
Output shaft speed sensor
Shifts 'out of phase' (Which could be anything!!)
Crank Sensor
Solenoid assembly malfunction

Now if the 'N' light is flashing, suggesting it IS one of the above (but this isn't guaranteed), you've still got to work out which - Again, without a code reader you're up that famous creek without a paddle, though you can perhaps narrow it down.... Before it locks into '3' what is the shift quality like? If it's okay, I'd be leaning towards the speed sensors. If it's rough, I'd be leaning towards one of the others.

Also - If you stick the car in Tip when stationary, and hold it in either 1st or second gear, does it still go into 3rd and lockout? If it does, again that suggests to my mind a speed sensor has gone loopy as the other componens (that are engaged DURING a shift) aren't being called into play.

BUT.... Whilst that makes sense to me, it is just guesswork - I think step 1 has to be to get the codes out that gearbox - I THINK Evoscan can this, can anyone back me up on that? Is there a NZ member near you with a copy of EVOScan you could borrow perhaps?

[VR4WGN]

Hmmm - which atf did you use? Amsoil or Mitsi's own DiaQueen SPIII? Or something else?

its SPIII

[VR4WGN]

Hmmm. It's a bugger trying to diagnose one of these boxes without getting the codes out of it.

Problem is without being able to 'Plug in' you're guessing. When it locks in 3rd, does the 'N' light flash about once a second? If it does, that does narrow things down a bit to one of these, according to the workshop manual:

Input shaft speed sensor
Output shaft speed sensor
Shifts 'out of phase' (Which could be anything!!)
Crank Sensor
Solenoid assembly malfunction

Now if the 'N' light is flashing, suggesting it IS one of the above (but this isn't guaranteed), you've still got to work out which - Again, without a code reader you're up that famous creek without a paddle, though you can perhaps narrow it down.... Before it locks into '3' what is the shift quality like? If it's okay, I'd be leaning towards the speed sensors. If it's rough, I'd be leaning towards one of the others.

Also - If you stick the car in Tip when stationary, and hold it in either 1st or second gear, does it still go into 3rd and lockout? If it does, again that suggests to my mind a speed sensor has gone loopy as the other componens (that are engaged DURING a shift) aren't being called into play.

BUT.... Whilst that makes sense to me, it is just guesswork - I think step 1 has to be to get the codes out that gearbox - I THINK Evoscan can this, can anyone back me up on that? Is there a NZ member near you with a copy of EVOScan you could borrow perhaps?

thanx heaps man,it chnges to 3rd normally,a little lumpy but thats normal for learn mode,but change to 3rd is a bit hard,then after a while it goes into 3rd lock(safe mode,N light flashes once p/sec,i will try leaving it running in 1st for a bit and get speed up for 2nd and try it and get back to you with answers,,i hate autos lol

[elnevio]

I assume you can't get past 3rd to see if 4th and 5th are ok. I will probably get a /pan and then shot for this suggestion - and someone can confirm whether it's an advisable idea or not first - but what if you put it into D, accelerate hard up to about 80 kmh (so the box stays in 2nd), nudge the selector into N at the same time as lifting off (so the box doesn't get chance to change up to 3rd), then once the revs have calmed down after a second or so, nudge the selector back to D and it should go straight into 4th or 5th. That way you can see if the higher gears are working and whether or not it's just 3rd.

BTW, I accidentally found this out when I accelerated away in D, and nudged the selector forward thinking I was in tip. Quick bounce off the rev limiter in N (already lifted off as I knew as soon as I did it what I'd done!), and I noticed selecting D put it straight into 4th (I was doing about 50 kmh). So I suppose this isn't recommended practice (!), but it might help with diagnostics.

[peter thomson]

Have you tried it on the road as it sounds as if you have just tried it while on stands which may be upsetting the ecu?

[Solardavid350]

I had that fault once only after track use...with new Amsoil oil too.
Maybe a temp sensor somewhere needs checking ???

[VR4WGN]

hi all i would like to thank you all for ALL your AWSUm input,you guys are like guardian angels lol,the Legnum was given back to its owner tonight so its all sweet,the fault was indeed as mentiond,a SPEED SENSOR was broken without my notice it was limp and loose so i took it out and the clip unit broke away from th sensor,put new 1 in and away with the fairys,chaes beautifully,and is almost out of learning mode already,owner is very happy,thank you to all of you guys,many thanx,now i can complete the NEW BONNET....this weekend hopefully

[eyedol]

This is Q ae? Its Ben Frm Chch.

That Tiptronic Gearbox I just put in did the same thing exept it decided to randomly drop from 4th to 1st by itself when I was going 60 Km/s (Quite Scary) Happened about 2 times over a period of a week and just about caused a huge pileup.

I was getting the same error the second time around as you were describing, turned out it was a dodgey speed sensor, replaced it and all was ok apart from 4th Gear Playing Up now :(

It is actually quite scary to know that could happen because of a speed sensor, it assumed I had stopped I guess.

[VR4WGN]

ye man mine was low on juice thats all,then the speed sensor clip was broken off,and replaced it now its like a warm pussycat purrin lol