Ford Ranger 4x4 problems

[Tanner moore]

Hi, just recently joined the forum, I have a 1998 ford ranger xlt 4x4, went out into some mud on Christmas night, 4x4 worked amazingly, it got stuck in 4x4 (wouldn’t shift out) but needed it anyways, shifted into 2wd after sitting, then I go to use 4wd a few days ago, was working strongly, than randomly starts getting weaker and weaker, then quits working, was still in low gearing, but no 4wd, got it to shift into 2wd, my brother had the same problem, wondering why the 4wd is doing this, checked switch and all other easy stuff, anything helps, thank you.

 

[Curious Hound]

When you say it gets weaker and weaker and then quits, do you mean that just the front wheels stop pulling? Or do you have trouble putting power to any wheels at all?

Have you checked fluid level in the transfer case? Do you have manual or automatic hubs? Are they locked in properly?

Sorry. But your description of the problem is a little bit odd. We will have to ask you a bunch of questions like this to understand what is happening.

There are some good troubleshooting articles in the "how to tech" section of this website. Be sure to check them out while waiting for an answer.

 

[Tanner moore]

Front wheels stop pulling, haven’t checked the fluid level, and not too sure if the hubs are auto or not, thinking they are auto because the 4wd works great than slowly quits, if they were manual wouldn’t it just not work at all?

 

[Curious Hound]

I'm not sure what years had the vacuum operated (PVH) hubs. Might be a slow vacuum leak allowing the hubs to disengage if you have that system. Someone with more pvh knowledge will eventually chime in here.

 

[4.0blue98]

Sure sounds like a PVH issue. Typically the hubs will just fail to lock in at all as opposed to working and then releasing. If you use 4wd frequently I'd either lock them permanently or get a set of manual locking hubs. I put AVM hubs on mine and they've been great.

https://www.therangerstation.com/tech/permanently-lock-your-98-00-pvh-hubs/


Here's a description of their action that seems accurate to me. Not sure if anyone out there has other ideas.

"Let’s start by discussing the finicky and extremely goofy PVH system, which Ford used mostly on the early Rangers. Here’s how it works: When the control module verifies the completion of a transfer case shift to 4WD using the contact plate position sensors, it activates the high-vacuum solenoid, supplying a vacuum of at least 11 in.-Hg to the hublocks for no longer than 60 seconds. This engages the hubs, which remain engaged after the vacuum source is interrupted. When the module verifies a shift to 2WD, it activates the low-vacuum solenoid, which supplies 6 to 7 in.-Hg vacuum to the hublocks for no longer than 30 seconds, disengaging the hubs, giving us 2WD. I kid you not; I wouldn’t make this stuff up.

Despite its eccentric ways, the PVH system works fine. Most problems are caused by the hublocks themselves. The PVH hub uses a plastic retainer ring with a steel circlip that secures the axle in place in relation to the hub seal. When this ring breaks, and they do, the axle will move toward the front differential, and the sealing surface on the axle will lose contact with the main vacuum seal. This is the beginning of the end. Besides intermittently losing 4WD, the lack of sealing allows road debris and water to enter the hub. Check for excessive end play in the axle. When replacing the retainer ring, be sure it snaps into the axle groove with an audible click."

 

[Tanner moore]

So would that be vacuum lines I need to replace?

 

[Jim Oaks]

You should read this page to better understand your hubs:

1999-2000 Ford Ranger PVH Hub Operation & Troubleshooting - The Ranger Station

Problem: 1999 Ford Ranger (107,000 mi.): 4X4 worked great a few months ago, with a slight squeak in the front right axle (when engaged). Now that it’s 10 degrees outside, the 4X4 won’t engage. The light comes on, I believe … Continued

www.therangerstation.com

 

[4.0blue98]

Jim has a better description. Most of the issues I've had were the seals in the hubs not the vacuum lines or reservoir. I personally don't think they're worth fixing. I'd just replace them or lock them.

I locked mine initially for about a year and it was fine but like the idea of manual hubs anyway so did the swap.