Engine/Transmission (1998.5 - 2002) SO Pump on HO Truck?

[GO 4LO]

So what's the final word on fitting an SO VP44 pump to an HO truck? The word used to be that this was impossible, but I've seen a few posts in the last year that indicate the SO pump drops right onto an HO truck without any electronics issues.



My truck deadpedaled twice over the weekend, so it appears I'll be replacing my pump soon . Thanks.



Chris

 

[GOT-Torque]

Do a search, the answer is out there. I can't remember which way worked, I am leaning towards a HO pump on a SO truck was ok with no other changes, but a SO pump on a HO truck was not. Sorry can't remember for sure...

 

[AFoulk]

If I remember right, I was told that its the other way around, the SO pump will work on a HO engine, but the HO wont work on the SO engine. Only thing is, while putting an SO pump on an HO will work, you still wont get quite the flow from the SO pump as you would if it were on an original SO engine. I was told the reason behind that was because the HO computer doesn't hold the solenoid open as long, so to get the full benefit of the SO pump on an HO engine, you'd have to swap to an SO computer too. Ofcourse, i could be wrong on all that too, I'm just telling ya what I was told.

 

[AFarmer]

It'll work just fine. Slap an SO on and go.

 

[GO 4LO]

Thanks for the help, guys.



Chris

 

[SRossi]

If I remember right, I was told that its the other way around, the SO pump will work on a HO engine, but the HO wont work on the SO engine. Only thing is, while putting an SO pump on an HO will work, you still wont get quite the flow from the SO pump as you would if it were on an original SO engine. I was told the reason behind that was because the HO computer doesn't hold the solenoid open as long, so to get the full benefit of the SO pump on an HO engine, you'd have to swap to an SO computer too. Ofcourse, i could be wrong on all that too, I'm just telling ya what I was told.

I learned first hand that this isnt true. The truck will run, but wont be able to go over about 60mph. Why would you want to swap to a HO pump anyways? Last I heard the SO pumps were making more power with electronics than the HO

 

[AFoulk]

I wasn't telling him to swap an HO pump onto an SO engine. I just mentioned that that wouldn't work because got-torque's response was backwards, saying that the HO would work on an SO engine and an SO pump wouldn't work on a HO engine.

 

[lcaad1249]

I've got a friend who when is HO VP44 went out unknowingly put a commercial VP44 off of a Freightliner or something. His truck runs fine, but he's been told that he's down about 100 HP over having a Dodge VP44.