band staying applied 700r4

[DryRye]

Had to rebuild 700r4 because front planetary exploded. Built several before with out issue.When testing this one on jack stands with gauges hooked up I can see and hear that the 2nd clutch pressure does not drop when it shifts to third.
so gauges read like this...line pressure-65,2nd clutch 65,and 3rd 65.
Band won't last long like this.Pulled valve body and triple checked everything is assembled right and nothing appears to be sticking.Swapped servo just because it's easy to do.Ant trans experts that can help me out?Trans is built to Raptor 3 specs.

 

[crazy4offroad]

I'm no expert by any measure but I found this, which mentions Raptor 3 details about 1/8 the way down the page...
http://www.transmissioncenter.net/700r4.htm

The Raybestos Pro Series black Kevlar band is used that holds in second and overdrive.

You may want to verify clearance on your intermediate and forward drum clutch packs, since the Raptor 3 spec calls for extra clutches. If your apply piston wasn't designed for the extra clutch/steel then it could be holding when it should be released. Only other thing I can think of, if you went through the valve body be sure to verify the order of your valves & springs. On my TH350 I had one spring backwards that had a small end and a large end and toasted my forward clutches. Good luck and post back what you find. Hopefully HotrodPC and oneluckypops will chime in on this when they get here, they were both very helpful with my trans questions.

 

[DryRye]

Just got an email from PATC(raptor trans).
They suspect the checkball behind the servo isn't releasing the servo pressure,maybe some crap in there.Will check tomorrow morning;working afternoon shift this week and next so off to work i go.
I'll post my findings.

 

[DryRye]

guess i was worried about nothing.
2nd clutch is supposed to show line pressure in 3rd gear.
all good.

 

[crazy4offroad]

Thanks for posting back, helps others learn something too!