On my 96 PSD with 4.1:1 gears, tranny would not downshift driving about 60-63 mph.
I have to slow down to maybe 53-57 and then stomp it.
Does this seems about right?
Everything on the drive train, including wheels and tires are stock.

 

so running 60-65 if you mat the throttle it won't downshift? Doesn't seem right to me.

 

He is running 410's... i know theres a point on the stock tranny where it should downshift but doesnt...

 

I got another 97 PSD with 3.5:1 and I could go from OD to 3 rd from about 67mph.

But now matter how I mash the pedal on my 96 with 4.1 when going 60-65 it would not down shift.

I remember someone had a graph of shift points on the trannys. Any help?

 

Mine wont down shift at about 70 ish if memory servs me right but with my 35's it makes my 4.10s more like 3.55s I think your trucks behaving normally cuz the older trucks with 3 speeds and 4.10s would top out at like 68 ish max.