Typically, when the VP is going out, it starts to lose power intermittently. Itll gradually get worse. Classic symptom of "dead pedal." And the pump doesnt always throw a code; usually when it does its too late. Actually, when it has a dead pedal, its alreay too late.

 

Just something else to add to my symptoms, the RPMs are going WAY higher than normal. I think the engine still makes power, its just not being put to the wheels. Note the other bit, when I manually shift it down to first gear, the responsiveness comes back.

Is there any way the VP44 would be causing that???

 

So your saying that the engine responds to pedal effort, runs fine, doesnt cut out, etc. just revs up when you try to accelerate? If thats what yours is doing, then its your trans. Mine used to do that. Convertor is slipping most likely. Could be internal too, but Id rule out the convertor before looking at anything else. The stock convertors are junk.

Explain more about what yours is doing, in different driveing situations too...and how often has it been doing that?

 

Thats exactly what I am saying. The engine responds, but I don't move off the line very fast at all. To get it just ROLLING the RPMs are in the 2500 range. I would agree that it is either convertor or transmission likely.

When I select '1'st gear instead of 'D' on the shifter, the truck will accelerate like normal, and then I pop it into '2'nd and then drive. I drive like that until I get to a point where i'm able to pull over and turn the truck off and back on.

Are there any sensors in the transmission or tq convertor that can go bad to cause anything like this? I had my truck hooked up to a friend's shop computer a while back and he said the governor pressure sensor was way high.

I only experience this loss of power off the line after I've driven above 50mph(on speedo, not sure actual speed) and I hit my OD gear. Then it only does it as long as the truck continues to run. A simple off and on of the ignition is fine. I've actually tested this on a roll in neutral when there wasn't much traffic. Because it resets so easily and never does the retard power mode unless I hit over drive, it makes me think electric. Would I be wrong thinking that? Are there mechanical things that get reset when you turn the truck off and on?

The only condition that effects the truck going into retard mode is hitting my over drive gear, there are no other conditions that cause it or effect it that i'm aware of. It has never done it to me without that. I live in a town where most speed limits are 30-40mph tops, and we have a bunch of ******* cops so going much faster than that is not a common thing.

The other bit about manually putting the truck in 1st gear, the truck actually lunges as if i were putting it into gear from neutral when I do that. Almost like its still in second gear(with no power from a dead stop) or somehow shifted itself all the way down to neutral or something.

 

I have replaced the APPS sensor and truck act the same , same symptoms and everything . I guess is the vp44 I just cant belive is the pump with the milage I have . So I take the chance and spend $ 570 on the sensor from the dealer and now I have one extra anybody wants one let me know .I'm taking the truck to the dealer tommorow . Thanks for all the help .

 

Has to be electronic. Theres no way it would do it ONLY after you hit OD if it were the convertor or something mechanical. Tell me this, if you turn the OD off, does that affect it? Like can you go above 50, say 65 or so, and it not do it? Try that. Im not sure how fast you can get w/o OD, but I hit 75 at 3500rpm the other day.

Was the pressure reading up and down on the computer? If it had a display, it should of had a graph. Normal pressure is a fairly straight line. If it peaks, and comes down, and goes up, and down, etc. then its the pressure solenoid or transducer. When you slow down to a stop, does the truck lurch? Or cruising around 20 or so? Thats a telltale sign of pressure solenoid...your pressure may be off, but it doesnt really sound like yours is suffering from the press. solenoid, because that would be fairly consistent.

Any tranny shops around you that could go for a ride? Or the dealer. Have them plug their scanner in and go for a ride and look at the graph in real time.

 

I do think yours is the pump. Unfortunately, thats about an $1100 bill. Hopefully they can get ya fixed. Post back what they find out...

 

Are you stalking me??? How do you know my truck lurches around 20mph? Hah, yeah, you definitely just picked my exact symptoms off. I've never tried to drive a steady 20mph before, and it definitely lurches. I've not had a chance to take it over 50 with OD turned off. I will test that as soon as I get some open road.

As for the computer, I wasn't actually looking at it. I was just sitting in the passenger seat while the the mechanic was driving and messing with the computer. He just told me the 'governor pressure' something or other was high.

I've also noticed my truck will refuse to shift out of 1st or 2nd if I've completely floored it, I don't do that too often so it never occurred to me as much of a problem. The truck will literally wind out the RPMs until I let off the pedal and then shift like it took a dump on itself. It will do this if I go to pass somebody and it down shifts to 1st or 2nd and I've got the pedal floored as well. Not just from off the line. However if i'm on the interstate and i'm in 4th and floor it and it drops to 3rd, it has no problem shifting back to 4th.

(Yes, I count obsessively. I can't help feeling the shifts and knowing what gear I'm in, I've done it since I was a child.)

I'm starting to realize there is all sorts of strangeness with this transmission =( I still love the truck though!

 

Dang. Busted! Yea it finally snowed up here so Im on vacation in Florida. Haha.

Yep, its lurching so its MOST likely the pressure solenoid and/or transducer. Id replace both at the same time. You might as well do a filter change while your in there, along with new fluid. I dont know if youd do i yourself or have somebody do it...

I bought the sensor and transducer, plus a filter, the day my tranny went out. I was planning on doing the repair the next day. Kinda ticked me off. And that was my billet race tranny...So I have extras when/if it ever does it again.

How long have you been driving it since it started acting funny? I drove mine for ~3 months before it went out. It turned out to be the convertor, but I really dont think it lurching like it was helped it any, if you know what Im saying. Id try to get it repaired soon if possible.

The sensor was $125
Transducer $75
Filter $30
Ive heard prices can vary quit a bit. I know of a guy that got the parts (minus filter) for $150. It really is nice not having the damn thing lurching and having to manually shift it! Let me know if you change those and whether or not it fixed it for ya. Good luck

 

Ok . So i pick up my truck from the dealer today . so whot they did was :replace defective boost pressure sensor ( i think this is map sensor ) and updated ecm for incrase in power . Truck runs good so far no problems . Total cost $ 202 not bad . Thank's to all the people for help .Merry Christmas to all of you .