GU ZD30 4SP 2004 Wont select Drive, need to take off in first

Hi all,

First time poster here.

Im having issues with my trans. it was completely rebuilt around 45,000 km ago and been serviced a few times. The trans wont drive when selecting D initially it only started doing this on cold morning and has gradually gotten worse. when it first started happening it took it in and they could not find anything wrong with it.

There are no issues selecting 1, 2 or reverse. i take off in first then run through the gears with no issues, i can then stop and take off in drive. Oil levels correct when cold and hot. as well the oil seems good as its still red.

Its a recommended trans place and the have had the diagnostics on it and no faults. The have dropped the pan and slight paste on the mag plug and slight ally though the oil. Nothing that would spark and issues or could be picked up with a camera. The Auto place has contacted a few people and gone into some system to see if they could find any info on the fault and the cant find anything or ever come across this.

I have searched this forum and quite a few posts over the years but no definitive answer, seems most people willing to uy um with it like myself. But now im ready to upgrade my beast and don't want to pass an issue on.

Hopefully someone in this brains trust can give an idea what can be the issue.

Any advise much appreciated

Possibly a sticky piston/valve in the valve body that frees up as temperature rises. That won't show as a fault code.

i agree with jff45 . perhaps add some nulon automatic transmission treatment g60 additive . iv'e had good results with other nulon additves in the past , might help to lubricate a sticky valve . otherwise you might have to leave the car with the mechanics overnight so they can drive it in the morning when it is cold to experiance the problem 1st hand . either way , get back to us and let us know how it turned out .

Hey,
It’s at the auto specialist and they have no idea. The had it over night and had diagnostics on and no electrical faults. They want to pull the trans apart.
I’m thinking I might just get them to strip and clean the valve body. Flush the oil system.