Hey guys my 86 F250 is still having transmission issues. Im shifting into second at 5mph and therd at 15mph. I have replaces the VRV and set it, replaced the vocuum modulartor and all the vacuum lines. Im not sure what to do from here. I even got frusterated and just started moving the VRV back and forith and nothing changed. Not sure were to go next
C6 still aint right!!!
- Thread starter Jmackk
- Start date
Go down and unplug the hose off the modulator and put a screw in it to block it. Now drive it. What does it do? It should rev way up and not really want to shift at all, but it might and it will be a very hard shift, if the stuff inside the tranny is working correctly.
It reves to the governor but wont shift up. The old VRV was clogged/plugged and the the trans wouldnt shift unless done manually, now its shifting way to soon. It runs great shifting manually, runs smooth, but if im in second at 30-35 and go from 2 into D it goes right into 3rd.
The trans has a governor also that varies the line pressure in the tranny. This along with the vacuum modulator is what tells the tranny when to shift, the modulator monitors the throttle position and the governor monitors road speed. I suppose there could be something wrong with the governor in the tranny. I have worked on a turbo 350 governor in the vehicle before, but never have messed with a c6. I don't know if it's accessible from the outside like the turbo 350 or not.
Dsl_Dog_Treat
I lost my face to the jaws of a poodle
Are the lines hooked up to the vrv correctly? Has a vacuum test been done on the vrv to verify its functionality?
Dsl_Dog_Treat
I lost my face to the jaws of a poodle
You have the lines routed correctly.
Have you seen the vrv adjustment thread in the tech articles?
Have you seen the vrv adjustment thread in the tech articles?
Ok so i have been out and tried setting it up again, the tech article here was much better than the other one I found. When i place my vacuum pump(hand pump) on then VRV and apply vac I have to keep pumping it to maintain vac. I check all the lines and theres no leaks. But when I apply the vac to the vrv(top) and the gauge(bottom) it will not hold pressure.
Dsl_Dog_Treat
I lost my face to the jaws of a poodle
Sounds like you found your culprit.
And I put in a new vacuum modulator, i bought a black stripe but when I received it there were no "stripes" on it. Just the standard gold finish with a black O ring. Is this going to have any affect on anything?
mariner45
Full Access Member
You should be able to adjust the modulator. There will be a small screw inside the tube and you adjust it to chnage operation - don't remember which way. It is easy and simple and you really need to try the truck out and adjust accordingly.
any chance the pin fell out when you changed the modulator?
And the no stripe one may be the problem. I used to have a scale chart to set modulators to the lbs spring pressure but ill be danged if I can find it. It came from a very old guy in a trans shop and he set them this way and checked/adjusted the new ones.
And the no stripe one may be the problem. I used to have a scale chart to set modulators to the lbs spring pressure but ill be danged if I can find it. It came from a very old guy in a trans shop and he set them this way and checked/adjusted the new ones.
The VRV has to be the Black one, the Green strip is for gassers, have no idea what a Gold one is for.
