last few times I started the car and went and put it in gear it wouldn't move. after idling for a few mins it will shift into gear (cold not shifting into any gear)

now I checked the fluid level the first time it did it and it seemed fine. it also didn't have that burnt smell to the fluid, it was clean and full. the dipstick is some kind of straight chrome one that attached up along the firewall with a plastic dipstick (never seen one like it) could it be wrong length and low on fluid.

it seems to shift alright when driving and doesn't slip.

any ideas

350 motor, with a 350 auto tans.

 

Most likely a hard seal in your first gear clutch pack. The seal does not work cold but once the fluid warms up it will work. It is a pretty common complaint also it is cause by age or over heating more so then miles. It could be a sticking valve also but they tend to be more erratic one time it will take 20 minutes at idle to free up next time it would free up in 10 seconds.

You could try changing the fluid and check out the pan and see what in the bottom. If your going to use it make sure you let the car warm up in park. If you try to drive and the seal is not sealing it will fry the clutches and the extra heat will cause the seal to fail completely.