Tranny Shifting Oddities

[Me&My250]

Good Morning All-
I have a 1985 Ford 250 6.9L w/the C-6 tranny.
It has developed some shifting querks and I'd like some advise on trouble-shooting this beast..

From a dead stop...
You must apply more than ample throttle....
2nd gear engages after 35 mph-
using ample throttle...
3rd gear engages after 46 mph-

From a dead stop...Using Manual Shift method- Normal throttle-
1st to 2nd .....no problem...
2nd to 3rd.....drops back down to 1st....

Kick Down Bar prevents shifting to upper gears entirely.-Must be disconnected....
C-6 Tranny shifting is authorative and tight w/no noise or gear banging, smoothe operation.
Since it is my understanding that the kick-down bar is really for said "Passing Gear"....I've never found that I need this extra boost of power for passing in traffic as my 6.9L has plenty of passing force without having to 'floor-it'...

Someone has told me to adjust a 'sensor' located in the front of the engine near the throttle linkage....this is found between the oil filler and the alternator....

This engine was rebuilt about 10,000 miles ago.
The truck has seen moderate use over the years, but it is well loved and maintained. By far, my favorite vehicle- period!!!
New glow plugs, starter(old one was stolen!!), alternator, tranny filter, fresh fluids & filters-
I only purchase diesel sold at the truck stops, as well.

Any help/advice is most graciously appreciated.
Thank You for your attention-ED

[WhiteGardens]

I found out with my C-6, that when you need ample throttle from a stop it usually means that the tranny pump is shot. I had the same issue with my reman tranny. My mech hooked up a pressure guage to the tranny and I had zero pressure from the pump, and the only pressure I was getting was from the torque converter.

Your forward clutches could be slipping too.

What does the fluid look and smell like??

The other shifting issues could be related or are symptoms of bad vacum pressure to the tranny. Could have a leak in your vac line or your vrv valve is bad or out of adjustment.

Do a search through the threads. CDNSARGUY has posted more than a few times on how to adjust the vrv valve.

I would also suggest having a pressure test done on your tranny, I think you can rent the guage from any autoparts store.

Good Luck

[Me&My250]

Good Morning-
The Modulator valve showed fluid in it...so it was replaced.
She's shifting good (again)....
Thanks for the Heads-Up on the VRV-
I just changed out the fluids & filter around April...still cherry red.