C6 still aint right!!!

[franklin2]

any chance the pin fell out when you changed the modulator?
.

That would better fit his symptoms wouldn't it? It's like he is getting too much vacuum at all times, which would pull the diaphragm and the pin back, making it shift early. The pin being missing would do the same thing wouldn't it? You would think a vacuum leak at the VRV would reduce the vacuum available at the modulator, making it shift hard and very late.

A quick way to determine this would be to pull the line off like I suggested and see how the tranny reacts.

 

[Garbage_Mechan]

That would better fit his symptoms wouldn't it? It's like he is getting too much vacuum at all times, which would pull the diaphragm and the pin back, making it shift early. The pin being missing would do the same thing wouldn't it? You would think a vacuum leak at the VRV would reduce the vacuum available at the modulator, making it shift hard and very late.

A quick way to determine this would be to pull the line off like I suggested and see how the tranny reacts.

Take a look back a ways on a thread I did on this very issue. I went through every scenario and ended up just adjusting the VRV "wrong". One good quick tip is removing and pluging teh line to the modulator.
If you then get very late harsh shifts, the trans it self is OK. The default if all mechanical parts are good is NO VACUUM=LATE SHIFTING. Since you have a hand pump, run a hose in the cab and you can do your own shift points. 0vac=late, 5 vac=maybe 2200 rpm 10=1800, not exactly but just an idea how it goes. Definitly should be a huge difference between 0 vac and 20 vac,if not problem is in the trans not vac system.
I finally tee's a gauge into line to modulator, and found I needed far less vac than VRV setting proceedure called for. Shifts about right with 7 to 10 in vac.

 

[Jmackk]

"The VRV has to be the Black one, the Green strip is for gassers, have no idea what a Gold one is for."

My VRV is black with a white "face plate"

All the Vacuum modulators I have seen have a gold plating/finish on th same as grade "8" bolts. The vac mod I removed had a purple stripe, the one I ordered was a "black stripe" but there is no stripe any were on it.

Then pin did fall out when I put the new vac mod in but i put the pin back in. Is the pin directional? Could it be in backwards?

I removed the line from the vac mod and plugged it. The truck just revved up to the governor and the trans did not shift at all. I replaced the line and once again it went into 2nd gear at 5mph and 3rd gear at 15mph. It does this no matter were I place the VRV.

 

[typ4]

The pin is not directional.
Get another purple stripe mod. and put in there, in the meantime crank the screw in about 6 turns or till it stops to raise the shift points.
If you cant get the right one let meknow or go to a trans shop.

 

[Jmackk]

Up date!!!

I got a purple vac mod for the trans, I only had time today to put it in and drive it around the block but it looks like the shift points went from 2nd at 5mph and 3rd at 15mph to 2nd at 10-12mph and 3rd at 25mph. Its not a bad spread since this is only my Daily(for know) but tomorrow I plan on trying to tune it all again. Thanks Type4, i was under the idea the purple one was incorect and would not have tried it.