Gearbox problem from top gear (auto)

[Artic]

Hi all, got a problem with my 99 vt Acclaim.
Gearbox changing is fine up to top in the auto, however if or when you accelerate from 50 or more 70kms a full on shunting starts like its missing but when you change down to 3rd all fine and dandy back up to top and smooth sailing till the next pass etc.
Is it the bands? Sensor? No warning light comes on at all.

Any ideas would be a big help.

Thanks
BJ

[accentstencil]

Spark plugs or leads are usually the cause of a miss under load, leads more often than plugs.

[Artic]

thanks for the reply,
if it is either leads or plugs, why only in top gear?

[MrSirWantalot]

thanks for the reply,
if it is either leads or plugs, why only in top gear?

Top gear would have more load than 1,2,3

[vx_commodore]

Had the same problem, It was a bad Spark Plug.
Only ever missed under load, Ie 4th/overdrive
Good Luck!

[som]

I agree,almost certainly plugs and leads but just possibly could also be a coil pack.I've mentioned previously on this forum that I never cease to be amazed just how sensitive these gearboxes are to engine tuning.My gearbox was supposedly RS about 60,000km ago when I needed plugs and leads and more recently I noticed the 3/4 gear changes were a bit ordinary again ,only to discover that the coil pack needed replacing.Good luck

[ucwepn]

I had a similar problem in overdrive/4th it would go on and off the throttle by itself (thats what it felt like) at certain low revs and would go away if I gave it slightly more throttle. The Auto let go shortly after a couple of weeks later in spectacular fashion lol

New rebuilt auto doesn't do it