727 with manual valve body

What would make my manual valve body upshift from 2-3 and down shift from 3-2?When i drive the car i shift 123 manually but if im driving throug town and stat to slow down i can feel it down shift from 3rd to 2nd,and if i go around a corner it will go from 3rd to 2nd and back to 2nd to 3rd.I didnt think a manual valve body was supposed to work this way,Any ideas?I dont want to burn this tranny up.

Is this a full manual or a semi manual with the kickdown lever?

Supposed to be full,no kick down

Manual VB is that MANUAL. If it's D and it's down shifting or upshifting, it's not a manual vavle body.

Look at the lever on the trans. If there is stub sticking up from where the lever slides onto the trans then it's not a full manual and you need to get a kickdown on it before you burn it up. A full manual won't have the stub for the kickdown lever.

hi
not true , i for one have built many manual vb and left the original kick down / throttle psi lever at full leingth !

make sure the gov has been removed .

may be someones vb kit screw up ???

also i have 2 vb turbo action , 1 i bought new at a dodge dealer in the eaarly eightys and one that came in a trade in trany and they both have a rod that will accept a kickdown linkage .
i installed one in my car for a while with a kd linkage just to fool some of my buddies about what i had , but even though the carb linkage worked it it did nothing!!

i have also built full manuels for the street that did use k d linkage to soften the shifts at low speeds !!!

An aftermarket full manual valve body will not have the provision for a kickdown lever. If it's a factory valve body that has been made into a manual then who knows what it ends up being or how it will work.

If this is a Forward pattern TF-3 kit, then they use the throttle linkage to control line pressure for part throttle shift feel. Removing the governor will cause all sorts of problems since there will be an internal leak.
In this kit and some others like it, they drill out or "Short circuit" the governor passage in the VB to force it into thinking it needs to be in third gear. All the valves in the valve body are still active and want to shift into third but when selected in 1 or 2, you are just holding it from upshifting. To over slimplify, the shift valves are doing the shifting,not the manual valve(like in reverse pattern VB's).
I had this exact problem before. What is happening is governor pressure is dropping and the shift valves sense this and want to downshift. In my case, I had an internal leak because of a rollerized rear support that I used didn't seperate lube oil with governor oil and created a leak path for high pressure governor oil to vent. Both these passages get affected in this modification and usally doesn't effect manual VB's because most of them have a custom seperator plates without the passages drilled. Another likly source cound be that the governor valves were removed and creating an internal leak.
Ask you transmission builder these questions,
1 - Who's Valve body and/or kit ?
2 - Does it have a rollerized rear support ?
3 - Did they remove the governor valves ?

If you are attempting to do any further diagnostics, Measure line pressure at the accululator port and see what you get. The pressure should be steady if the throttle linkage is rigged. Also , post pictures of the VB.

I agree manual is manual...u must do the shift...u might have something different