Recently I've noticed my 4L60E won't kickdown when you go to WOT. It will kickdown one gear from 4th to 3rd at higher speeds but not two gears as it had in the past.
I've also recently added an aftermarket tach and now notice my RPM's on the factory tach are quite high as compared to the aftermarket. At idle the factory tach reads 1000 while the aftermarket reads 600 RPM.
Both of these seem to have happened after I had the trans rebuilt. Has anyone run into these issues before? My trans guy said nothing he did would have caused these issues. Any ideas out there?

 

idle my car car sits at 500 or a little under. do you have a cam or anything?

 

sort of odd. it never downshifts 2 gears? if you're going over 70 it's only gonna go to third. what speed are you trying this at?

 

you may get more responses i you post this in the transmission section