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Discussion Starter · #1 ·
C5 case with C4 valvebody and transgo -3 manual kit and H servo. This started right after going from -2 to -3 kit. No vacumm to modulater. Linkage is adjusted properly.

Shift into 3rd is ok then it will go to neutral under power. Riding in 3rd and get on it and it goes to neutral. It's not just a flare, you must shift to neutral or 2nd and back to 3rd to reengage 3rd.

What should I look to first? What will disengage 3rd gear? I'm ASSuming it is something in the valvebody. Any ideas before I tear it open again?
 

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hmmm, dunno could be a bad seal in teh forward direct clutch.
Could be a leak in the valve body.
 

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Discussion Starter · #3 ·
Wouldn't the seal take out all fwd gears?
I put a new gasket on the vb, that didn't help. Maybe I should put it back to the -2 specs and see if that does anything?
 

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Does it happen in reverse too?
The High / Reverse clutch could have too much travel in it and be losing pressure when the piston travels past the sealing surface.
You might check the intermediate servo piston, cap and seals. It is possible to lose pressure throughthe intermediate servo to the case port to sump if it is cracked or the seals are bad. Chech it first because their is no removal of the tranny required and it can be repaired without removal of the transmission.
 

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Discussion Starter · #5 ·
I never get on it in reverse so I would need to try that. It shouldn't be the clutch clearances, that was checked recently. Could be the servo though. If the reverse is ok i'll change the vb back and see if that's it.
 

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The servo has nothing to do with your high gear operation. The common part between high and reverse is the high/reverse clutch. If you have the same thing happening in reverse and high then chances are that it is in the high/reverse clutch.
In a manual valve body I am not sure what would cause the clutch to disengage. I can see if it ran out of fluid - a deep pan and deepened pickup should prevent that, or if the clutches were not up to holding the HP they might slip but the pressure in a manual valve body usually prevents that.

check list:
At least 5 frictions in both clutch packs?
Deep pan and deep pick-up?
tranny filled - in park at an idle?
Correct fluid used - Type F?
Any cracked bodies that could spill fluid under high pressures?
Pressure high enough to pop off the main pressure relief under the filter tab?

That last one may deserve a look. If that little valve pops then all the pressure is dumped until you shift into neutral or park and then it resets. You might have to replace the spring or add shims to keep it from popping off, or reduce the main pressure to a slightly lower pressure.
Paul
 

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Discussion Starter · #7 ·
Thanks for the info Paul. I'll try the last one. Just finished polishing all the spools in the VB as some were not moving as well as they should. We be putting it back together soon.
 
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