Welcome to TDS........I would suggest you:
Do a band tightening first then a VRV resetting......
Raise or shinney under the blocked vehicle.
Clean all the dirt from the band adjusting screw, remove and discard the lock nut.
Install a new locknut and tighten the adjusting screw to 10ftlbs torque.
Back of the adjusting screw exactly 1 1/2 turns.
Hold the adjusting screw from turning and tighten the locknut to 35-40 ftlbs.
Lower or shinney out from under truck, remove blocks.
Our member James posted this info........
How to adjust VRV
You don't have the engine running for the test, you need to apply 20" vacuum to upper VRV port and attach vacuum gauge to lower VRV port. The lower port is the one that goes to tranny, the upper to vacuum pump.
You have to maintain 20" througout this test. If it drops off you need to pump it back up.
Remove throttle return spring, cycle throttle lever 5 times from idle to WOT. Make sure 20" vacuum is maintained on upper port side.
Move throttle so it is 0.515" (33/64") from wide open (they make a tool for this). Vacuum gauge should read from 6-8" of vacuum. If incorrect adjust VRV to 7".
Again apply 20" vacuum, cycle throttle from idle to WOT 5 times. Return to idle. Gauge should read at least 13".
It says if you can't get the 7" or the 13" to replace the VRV. If VRV checks out maybe the diaphragm (modulator), line from VRV goes to the vacuum diaphragm I believe. Can't find any adjustment for the diaphragm but I think there is a little.
Basically all you need for the test is a vacuum pump (handheld type), vacuum gauge and a ruler to measure 1/2" or a 33/64" drill bit in lieu of the .515" tool. And a screwdriver for any adjustment needed.
Please be so kind as to put much needed info in your signature, go to "My Home" at the top of the page then "Personal info" click "Edit" put "all known" particulars for your truck/van in the signature block, any other info you feel worthwhile in other parts of this area. Fill in the "geographic location" too it is just as important, members can then direct you to the best known suppliers for parts, repairs, fuel etc closest you by location/ area/country. You could be just around the corner from a member willing to assist you or a parts store with what you need..