No reverse when cold with VN v8 t700

[v8slrtorana]

Can anybody tell me whats wrong with the turbo 700 in my car, and if its a common problem.
When cold, my turbo 700 will not go into reverse, unless you wait say 5 minutes.
While waiting for something to happen, it makes some quiet growling nosies, like the box has no fluid in it.
It does select forward gears, but takes 30 secs when cold.
When normal operating temp, every thing is normal, selects forward and reverse fine.
When cold or hot, once it has selected a gear, you boot it, the tyres spin
I changed the oil the other day to a dexron 2 type oil, and its much better.
Is the problem in the valve body, or else where?
Ive only owned the car for about 4 days, and the tyres have never been spun in anger.
Can someone please explain the purpose of the boost valve.
Thanks.

[greenfoam]

I would have said its just running low on oil if you can't get a gear when it's cold but since you have changed that I'm out of ideas

[Blown V6 Hatch]

Pretty simple, your auto is stuffed! Pretty common for T700's to get lazy when cold and are on there last legs.

[RabidDog_12345]

Pretty simple, your auto is stuffed! Pretty common for T700's to get lazy when cold and are on there last legs.

mine did the same, started losing reverse when cold, then started to delay in D as well, then it started slippin changing to second... then when i was doin its last burnout BANG!, then i whacked a manual in,