Eric - just realized you have a 47RH. That could be a whole different ball game. Would explain the differences.
Also, at 600 hp, with a Dana 70, I'm a little more nervous.

'Babyjoe' has a 47RE, like mine .... so maybe he needs to be a little more cautious, too??
Just a guess.

RJ

 

Well, my cousins 2.6 truck has a 47re(97), and his would hold 2nd gear. Now he has 4:88's and runs 3rd, and it holds 3rd gear all the way doen the track. It is a full billet Goerend. It could possibly be differences in the valve body between the 2 transmission builders. Do you know what RPM you were at when it downgeared? I know mine is usually around 2k RPM when the sled stops me.

I didnt realize you had a Dana 70 still. I think you are better off not pulling in that case They like to twist the pinion shafts off, and I think you have the power to do it for sure!

Eric