Autobox takes time to shift at first start

Started by Valentin, 11 June 2026, 17:14:44

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Valentin

Hello everyone,

Almost all is in the title.
After starting the car the first time of the day, when I begin to drive it takes some times to shift from 1st to 2nd gear. It takes like around ~300m (1000ft) then the car quickly shifts into 2nd and 3rd.

I have read in the user manual that for faster catalytic heating purpose, the car forces to stay on low gear on the first few meters. But I also tried to let the car make its cold start alone and heat without moving. Then, even if the cats are hot enough, the car doesn't want to shift like if it was cold. I guess then, there is nothing to do with the cats heating.

Winter or Summer, exact same story. I also tried to stay in D on the driveway and wait a few seconds in order to heat up the gearbox oil. Nothing changes.

Is it a normal behavior or do I need to make an oil change of the gearbox to improve the thing ? I have no idea if the oil has already been changed before I buy the car, but appart from that weird behavior at first start, the transmission shifts really smoothly and is a real pleasure to drive.

Doctor Gollum

Fluid level has to be the starting point.
Onanists always think outside the box.

TheBoy

Defo check fluid level as first port of call for any autobox issues.

If you have the tools, also check the live data on the engine coolant temp sensor and ensure its viable.  This is a different sensor to what feeds the dash gauge.
Grumpy old man

Valentin

Thanks guys, I will check the level once back to home. I don't have live data tools. What do you recommend to buy ?

TheBoy

On a 2.5/3.0 V6, OBDII tools won't work, sadly.  Not sure what else is out there, short of real Tech2.

You may have to use a meter, and try to find documentation for the sensor to convert to approx temp.
Grumpy old man

Valentin

Actually I have a VXDIAG VCX NANO that I bought few years ago for my 2012 Astra GTC. I guess I have Tech2Win on my other laptop. Do you think it could work ? Because I thought the 96' ECU was Tech1 and not Tech2 compatible :-\

https://www.eobdii.fr/vxdiag-vcx-nano-for-gm-opel-gds2-diagnostic-tool-wifi-version.html

johnnydog

I have owned a good few Omegas over the years - all 2.6 /3.2 V6 models.
The symptons you describe - they all did it for the initial drive of the day, but the 2.6's held on to 1st gear a little longer than the 3.2's.. After the1st gear change into 2nd, the gear change was then as you would expect.
Unless the holding onto 1st gear is particularly excessive, I wouldn't worry about it as it appears to be a usual trait of these gearboxes.
2002 3.2 Elite saloon, 2003 3.2 Elite saloon & estate

STEMO

Always worth checking the fluid level, it's a simple job and may cure any misbehaviour.
Diesel till I die

TheBoy

Quote from: Valentin on 12 June 2026, 11:00:20
Actually I have a VXDIAG VCX NANO that I bought few years ago for my 2012 Astra GTC. I guess I have Tech2Win on my other laptop. Do you think it could work ? Because I thought the 96' ECU was Tech1 and not Tech2 compatible :-\

https://www.eobdii.fr/vxdiag-vcx-nano-for-gm-opel-gds2-diagnostic-tool-wifi-version.html
(Genuine) Tech2 can read all Omega V6, including pre 1997.  The only ECUs a Tech2 can't read are 94/95 diesel (ie, those with the DDE2.0 ECU) and pre 96 2.0l 4 cylinder petrols (the ones with a 2 digit fault code, post 1997 Simtecs moved to a ODBII like 4 digit fault code system).  All 2.5/3.0 used the same Bosch Motronic 2.8.x series of ECU.

I assume Tech2Win should read the same ECUs if the VDI is up to the job.  Given that you have it, give it a go and report back.
Grumpy old man

Valentin

Quote from: johnnydog on 12 June 2026, 11:57:22
I have owned a good few Omegas over the years - all 2.6 /3.2 V6 models.
The symptons you describe - they all did it for the initial drive of the day, but the 2.6's held on to 1st gear a little longer than the 3.2's.. After the1st gear change into 2nd, the gear change was then as you would expect.
Unless the holding onto 1st gear is particularly excessive, I wouldn't worry about it as it appears to be a usual trait of these gearboxes.

I understand the purpose of warming up the engine and two friends have 2.6 and 3.2, they also have this behavior. But I find strange that the manufacturer obliges the car to run over 4000rpm when cold, just because it's programmed like that. If someone is not conscientious or doesn't care about the car, he can reach 30mph in first gear and slowly destroy the engine day after day. This is why I think there is something else :y

cam.in.head

#10
easiest way round it ( assuming level is correct ) is just to press the snow button as soon as you want it to change .then press it again once it changes and then youre into normal driving . thats all i do when it annoys me although im pretty sure it only does it  once from cold

johnnydog

Quote from: Valentin on 12 June 2026, 14:42:57
Quote from: johnnydog on 12 June 2026, 11:57:22
I have owned a good few Omegas over the years - all 2.6 /3.2 V6 models.
The symptons you describe - they all did it for the initial drive of the day, but the 2.6's held on to 1st gear a little longer than the 3.2's.. After the1st gear change into 2nd, the gear change was then as you would expect.
Unless the holding onto 1st gear is particularly excessive, I wouldn't worry about it as it appears to be a usual trait of these gearboxes.

I understand the purpose of warming up the engine and two friends have 2.6 and 3.2, they also have this behavior. But I find strange that the manufacturer obliges the car to run over 4000rpm when cold, just because it's programmed like that. If someone is not conscientious or doesn't care about the car, he can reach 30mph in first gear and slowly destroy the engine day after day. This is why I think there is something else :y

I would say 4000 rpm is definitely a lot higher than the revs that my Omegas get to when holding on to 1st gear when setting off after 1st start up. Although on the occasion it does hold onto 1st gear, I'm mindful not to let the revs get too high (especially being cold) until it does make the first gear change.
2002 3.2 Elite saloon, 2003 3.2 Elite saloon & estate

Doctor Gollum

Is the AR 25/35 adaptive?

ie does it adjust the shift points according to driving style?

Another consideration for a pre facelift car is that it has  mechanical throttle control. Is it beyond the realm of possibility that it's out of adjustment... :-\
Onanists always think outside the box.

TheBoy

Quote from: Doctor Gollum on 13 June 2026, 21:01:48
Is the AR 25/35 adaptive?

ie does it adjust the shift points according to driving style?

Another consideration for a pre facelift car is that it has  mechanical throttle control. Is it beyond the realm of possibility that it's out of adjustment... :-\
All Omega TCM's are adaptive, but this is a first change only, so not the adaptions.  They do hang onto 1st gear a bit, but this sounds excessive.

Can't see how the throttle (or ICV) would make a difference TBH.
Grumpy old man

Doctor Gollum

Quote from: TheBoy on 14 June 2026, 15:51:25
Quote from: Doctor Gollum on 13 June 2026, 21:01:48
Is the AR 25/35 adaptive?

ie does it adjust the shift points according to driving style?

Another consideration for a pre facelift car is that it has  mechanical throttle control. Is it beyond the realm of possibility that it's out of adjustment... :-\
All Omega TCM's are adaptive, but this is a first change only, so not the adaptions.  They do hang onto 1st gear a bit, but this sounds excessive.

Can't see how the throttle (or ICV) would make a difference TBH.
Might it be lifting the cold start idle speed? Possibly by way of an air leak or defective sensor? Obviously I haven't ever owned the suboptimal earlier cars, so never got that involved, although I have worked on a few...
Onanists always think outside the box.