i had my truck on a lift welding in a bung for a wideband yesterday. when i started the truck in neutral the tires started spining and the speedo was showing 30mph. is this normal?

 

The tires wasn't spinning 30 were they. It is normal for them to spin a lil bit but not 30 mph in N..

John

 

the speedo was showing 30mph but i didnt have a way to verify the speedo was correct. they were movin pretty fast

 

does it go on the ground? if so you might wanna check ur tranny. if not i doubt they were really goin 30 so ur probably ok

 

yes it is normal. I have pulled 3 transmissions in the past 2 months now and every time it has done the same thing as yours when the new one went in.

 

It's just the 3-4 clutches dragging. There's no torque to it. Set the parking brake if it's creating a dangerous situation.
You will also notice that in neutral if you rev the engine you'll feel some propullsion. This is caused by centrifugal force slinging the residual fluid in the 3-4 apply piston cavity to the inner circumference of the drum where it can impart some apply pressure to the clutch pack.