Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[less]

Hi all. As said, had problem with box today. Was driving fine but after motorway run lost drive - engine just revving as if out of gear.

Turned off and restarted then drives ok. Have done this a couple of times so far.

Seems unlikely to be fluid if it 'fixes' itself after a restart?

Any ideas anybody?

No visible leaks or evidence of leaking but I am going out to check oil level anyway

[Welung666]

Could still be low fluid levels. Switching the car off and restarting lets the ATF run back to the sump. Have a look in the maintenance guide index for checking the ATF level

[pscocoa]

ah my favourite - change crank sensor first and see how you go - how many miles has the car done - about 80000?

If crank sensor not the issue then ATF and filter change next

[less]

Well, I wasn't expecting that!

I got the car on the drive and jacked up the front to level the car. With engine hot and running, and having cycled through all gear positions, I removed the level plug and oil poured out. Difficult to be exact, but somewhere between 0.5l and 1l.

I know it was about right in september, as I had recently got a 1700 code and suspected low oil might be the cause.

Red herring? possiby. What else is likely to cause these (still present) symptoms?

[less]

ah my favourite - change crank sensor first and see how you go - how many miles has the car done - about 80000?

If crank sensor not the issue then ATF and filter change next

I changed crank sensor about 6 months ago (genuine GM). Why would that affect the gearbox?

It sounds and feels like a slipping clutch, which made me think of low fluid.

[pscocoa]

for me the problem started exactly as  you describe and then it would clunk back into gear which may sometimes cause the car to go into limp mode. You then turn off and turn on and problem would go away.

Crank sensor is sending engine speed signal to gearbox and if there is lets say an error in the info the gearbox receives then I am assuming a mismatch of speed and gear ratio is detected - hence the default to safety mode.

Changed crank sensor and cleared codes last Jan/Feb and clear since - but also changed ATF and filter prior to it happening the last time. Either way I have thus far avoided a far greater expense and time committment if had delved deeper.

Other causes can be a gearbox solenoid and bits of thrust washer in ATF which you need to look out for when draining gearbox.

[Kevin Wood]

for me the problem started exactly as  you describe and then it would clunk back into gear which may sometimes cause the car to go into limp mode. You then turn off and turn on and problem would go away.

Crank sensor is sending engine speed signal to gearbox and if there is lets say an error in the info the gearbox receives then I am assuming a mismatch of speed and gear ratio is detected - hence the default to safety mode.

Changed crank sensor and cleared codes last Jan/Feb and clear since - but also changed ATF and filter prior to it happening the last time. Either way I have thus far avoided a far greater expense and time committment if had delved deeper.

Other causes can be a gearbox solenoid and bits of thrust washer in ATF which you need to look out for when draining gearbox.

Has yours been OK since we took a look earlier in the year?

I'm in Camberley on Saturday by the looks of it - be happy to check it again for codes if you like?


ATF fluid does apparently expand as it ages. That sounds like a lot, though. Perhaps it was overfilled, although I can't see that causing it to malfunction.

The other possibility is that (e.g.) the fluid pump in the gearbox is faulty meaning that it is not keeping the torque converter and other parts of the gearbox full of fluid therefore more fluid sits in the sump than would be normal with the engine running.

What condition was the fluid in? Nice clear red colour or burnt brown? Any black particles in the fluid?

I would try the cheap fixes first. ATF change and correct the level, looking for any bits of thrust washer in the sump, then change the crank sensor.

Kevin

[pscocoa]

for me the problem started exactly as  you describe and then it would clunk back into gear which may sometimes cause the car to go into limp mode. You then turn off and turn on and problem would go away.

Crank sensor is sending engine speed signal to gearbox and if there is lets say an error in the info the gearbox receives then I am assuming a mismatch of speed and gear ratio is detected - hence the default to safety mode.

Changed crank sensor and cleared codes last Jan/Feb and clear since - but also changed ATF and filter prior to it happening the last time. Either way I have thus far avoided a far greater expense and time committment if had delved deeper.

Other causes can be a gearbox solenoid and bits of thrust washer in ATF which you need to look out for when draining gearbox.

Has yours been OK since we took a look earlier in the year?

I'm in Camberley on Saturday by the looks of it - be happy to check it again for codes if you like?


ATF fluid does apparently expand as it ages. That sounds like a lot, though. Perhaps it was overfilled, although I can't see that causing it to malfunction.

The other possibility is that (e.g.) the fluid pump in the gearbox is faulty meaning that it is not keeping the torque converter and other parts of the gearbox full of fluid therefore more fluid sits in the sump than would be normal with the engine running.

What condition was the fluid in? Nice clear red colour or burnt brown? Any black particles in the fluid?

I would try the cheap fixes first. ATF change and correct the level, looking for any bits of thrust washer in the sump, then change the crank sensor.

Kevin

Sounds good - will check if we are travelling somewhere again and send PM later in week if we are not - will Mrs be with you?. I have a Multiscan but that of course won't help with many code checks  - VX had a reader on it 2 weeks ago during MOT but reported nothing - not that I would ever trust them to be conclusive ever since they told me I had a 5 speed auto box!!

[less]

for me the problem started exactly as  you describe and then it would clunk back into gear which may sometimes cause the car to go into limp mode. You then turn off and turn on and problem would go away.

Crank sensor is sending engine speed signal to gearbox and if there is lets say an error in the info the gearbox receives then I am assuming a mismatch of speed and gear ratio is detected - hence the default to safety mode.

Changed crank sensor and cleared codes last Jan/Feb and clear since - but also changed ATF and filter prior to it happening the last time. Either way I have thus far avoided a far greater expense and time committment if had delved deeper.

Other causes can be a gearbox solenoid and bits of thrust washer in ATF which you need to look out for when draining gearbox.

Has yours been OK since we took a look earlier in the year?

I'm in Camberley on Saturday by the looks of it - be happy to check it again for codes if you like?


ATF fluid does apparently expand as it ages. That sounds like a lot, though. Perhaps it was overfilled, although I can't see that causing it to malfunction.

The other possibility is that (e.g.) the fluid pump in the gearbox is faulty meaning that it is not keeping the torque converter and other parts of the gearbox full of fluid therefore more fluid sits in the sump than would be normal with the engine running.

What condition was the fluid in? Nice clear red colour or burnt brown? Any black particles in the fluid?

I would try the cheap fixes first. ATF change and correct the level, looking for any bits of thrust washer in the sump, then change the crank sensor.

Kevin

I was wondering if a blocked or partially blocked filter might have the same effect? Anybody know/had similar symptoms with these boxes?

(The fluid that came out was unexpected so I caught it in a standard oil change container which has lots of black oil/sludge in so difficult to gauge accurately, but it looked more brown than red.)

[less]

Oil and filter change next then 

I am sure there was a how to but I can't find it despite several searches. (Although I can probably figure it out easily enough, the guides often warn of 'gotchas' before I rediscover them.  )

Also, do I need to change the filter or clean it? how much oil is needed? Opie oils likely the best supplier? Gasket set required?

Any help with these questions would be much appreciated  8-)

[Kevin Wood]

There's a chap who sells a set of sump gaskets plus filters for about £30 in the back of Straight 6 news if you are an ABS member. Filters can be cleaned instead though.

Condition of the fluid, the filter that comes out and any debris in the sump will offer vital clues as to the condition of the box.

Kevin

[pscocoa]

Oil and filter change next then 

I am sure there was a how to but I can't find it despite several searches. (Although I can probably figure it out easily enough, the guides often warn of 'gotchas' before I rediscover them.  )

Also, do I need to change the filter or clean it? how much oil is needed? Opie oils likely the best supplier? Gasket set required?

Any help with these questions would be much appreciated  8-)

http://www.omegaowners.com/forum/YaBB.pl?num=1211201164

[less]

Oil and filter change next then 

I am sure there was a how to but I can't find it despite several searches. (Although I can probably figure it out easily enough, the guides often warn of 'gotchas' before I rediscover them.  )

Also, do I need to change the filter or clean it? how much oil is needed? Opie oils likely the best supplier? Gasket set required?

Any help with these questions would be much appreciated  8-)

http://www.omegaowners.com/forum/YaBB.pl?num=1211201164

Many thanks for that pscocoa - it all helps 

[Pete Elite]

If the thrust washer has broken up is it easy to change it?

Thanks,
           Pete.

[sassanach]

imho yes.