Manual valve body 727 - 3rd gear won't engage under full throttle

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wahzinaplymouth

wahzinaplymouth

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Hi Gang! Having some issue getting my 727 to shift into 3rd gear under full throttle.
Some background here- The trans has a reverse pattern, manual shift valve body in it. The 1-2 shift if great, but when I go to shift into 3rd under full throttle, the trans will not shift. If I let off the gas some, it will shift, and then feels great once I get back in it. Under light load, it will shift. Obviously this is not ideal for a drag racing application. Any ideas why this would occur? Might I have a sticky servo, or band out of adjustment? Thanks in advance for any responses.
 
You have a half done manual valve body, as manuals are literally in the gear the shifter says it is no matter speed or load.
 
Is this something that just got built? Or converted to rmvb ? Or??? U may have to adjust ur manual valve or something is left out or installed wrong. Kim
 
Trailbeast, not sure what you mean by half done?

Kim, yes and no on the just built. This was a swap the guts into a different case build. It worked flawlessly prior but due to a case that had cracked, I had to swap the internals into another case.
Can you elaborate on "adjust your manual valve"? What would you surmise could be left out, or installed wrong?
Pretty sure nothing was left out, and it will shift into 3rd under light load. It is very much a mystery as to why it won't physically shift into 3rd under full throttle.
 
They should literally be in whatever gear the shifter says until it is moved to another.
Meaning a full manual should be in 3rd if you put the shifter in 3rd before you even start rolling.
You said yours shifts 2-3 late with more throttle, and earlier with less so the "full manual" and "shifts late" just don't go in the same sentence together.
 
or ur shift linkage could need alittle tweaking.....Did u use a new gasket and seal kit when u swapped the guts, r the bands set right, what r they set at, did u transfer the front servo, and is it the controlled load servo. which is 71 up or the 70 down front servo, how many springs in it, what is the front servo lever ratio and lastly did u happen to break a sealing ring on the pump..............kim.........
 
Sorry if I'm confusing people here. I'll see if I can catch what everyone has asked.
Fluid looks and smells great.
I think the shifting early and late are how you are interpreting my crappy explanation. If I do not let out of the throttle, it won't shift, shifter position be damned. I have to physically let out of the throttle for the shift to occur. Cable adjustment has been checked and rechecked.
Bands were adjusted by my trans guy so I have no reason to believe they weren't adjusted correctly and to factory recommended specs, but not discounting that either.
I wish I had taken pics or documented better what was inside this beast. I'll have to confer with the guy that actually did the assembly. I believe this to be a pre 70 piece and a stock ratio lever. 3.2 maybe?
Right now I am thinking a seal was perhaps knicked during the assembly. Nothing else is making sense right now. I haven't had a chance to get it up on a rack and drop the pan on it yet either. That will definitely rule some things out like a slipping drum or mis-adjusted bands. Would there be any issue with something like 70 and down guts and 71 up case?
I appreciate the input though guys.
 
a pressure test on the base(middle) and front servo could tell you some useful information. RMVB the manual valve dictates the gear, the governor circuit doesn't apply, so if you just moved all of the parts to another case,verify no pressure loss issue.
 
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