6.2l VRV adjustment...

[Big Ray]

I learned sumthin, baabaa looey!


I knew it was adjustable with the mounting screws ala a TPS...what I didn't know was the collar with the 4 prongs is an adjustment nut.

My rig has shifted late and hard since I had it - was at max adjustment already.

I turned the collar out 1 full turn & made a test drive. It is near the middle of the screws range now. And it drives b-e-a-u-tifully!

Shifts into D right at 33 mph without the hardness it did have.

Happy Fat Man dance!

 

[Big Ray]

here's a pic....the "nut" holding the cap on is adjustable...


p.s., this applies to TH400 equipped rigs...you 700R4 guys have a different switch that controls your torque converter lock up.

 

[diesel4me]

The VRV on my pickup never worked right from the day I got the truck--tried moving it around on the slotted thing and it didn't help much..

At the suggestion of a local tranny rebuilder,he said to just run the vacuum hose from the vacuum pump right to the modulator direct,then screw in the little adjustment screw on the modulator till it just bottoms out,then back off a tad..been ten years now,its still shifting into second firmly at 15-20 mph,and drive around 25 at light throttle..downshifts when its supposed too also...he said this will keep the line pressure high enough to avoid any slippage,but also allow it to upshift at a more reasonable speed and not slam into gear..

Before it would wind up to 30 in low and slam into second,and would not go into drive until at least 40-45 mph,and shift hard..and also feel like it was coasting in neutral if you let off the gas too..it only does that in drive when your crawling along in first or second under 20 mph now..if I shift manually into second I get normal engine braking though..I've beaten this tranny pretty hard plowing,I would think it would have died by now if this was harming it..

I guess from what I've read,the VRV makes the constant vacuum from the pump variable,just as it would be on a gas engine--maximum vacuum at idle,less at part throttle,and zero wide open..

I have seen cable operated modulator conversion kits for engines with superchargers,to eliminate the vacum control feature..if they were not so costly I would have bought one..

 

[Big Ray]

it was nice driving to work today...shifted smoothly at 35 mph.

much more enjoyable ride

 

[Big Ray]

update: my VRV finally took a chit. I dissected it & tried to clean it up & see if I could fix it, it's dead.

Did learn how it is suppose to work though. There's a disc with a tapered groove that a follower rides in. The follower is attached to another disc inside the tower of the valve by a short piece of wire. This disc is held open by the thick part of the taper.

As you apply throttle the first disc turns and moves to the thinner part of the taper. At this point the second metal disc in the tower closes, allowing vacuum to be applied to the modulator.

There's also a small electrical switch that closes in the valve, but I'm not sure what it does yet.

When my new one gets her I'll take the old one apart & post some pictures.

This is on a TH400 rig, the 700r4's have a different set up.