4WD only 1 Front Wheel Turns, No PVH Hubs, 4WD engages and disengages fine.

[danno]

Hi All,

I am quite confused. I have 2000 ranger ( 02/00 build). It's a farm truck, non-highway use. Recently it has left me setting a few different times in the snow. It will sit there and spin 1 back tire while in 4WD and the other tires sit motionless. It seems to have loss some power as well, over the past year or so, but I attributed that to blown-out exhaust system and lack of regular maintenance (air, fuel filters etc.) It also had some clunking earlier in the year but that was solely when in 4Lo. So I get the truck back on flat ground and jack the truck up so all 4 wheels are off the ground. Put it in 4 Hi and sure enough, all 4 wheels turn. However, I could stop both of the front tires (wearing leather gloves) fairly easily (if I stopped one, the other would keep spinning), doesn't make any strange noises or grinding. I noticed that one of the connections to hub was electrical taped and wiggled it some, which I found it helped some with the resistance and made it a little harder to stop the tire. I took it off the jacks and tried again, sure enough, got stuck again, same problem. The truck does not have PVH hubs and from everything I have read, most models up to a 2001 use the pvh system which makes it extremely difficult to find any answers.

So my question is A) why under load would my front tires be struggling in 4wd, and is there any remedy to get both front wheels turning at full power? B) what kind of 4WD system is in my ranger because it doesn't make any sense from what I have read, the only two connections going to the hub are a brake line and an electrical line which I'm thinking is just a speed sensor.

PLEASE any help would be super appreciated.

 

[Shadowrider6661]

Welcome to TRS. I'm not well versed in the newer Rangers and the terminology people use. This may be a stupid question, but what does PVH stand for ? I had problems with my 97 in January, the 4wd went out on it while I was coming back from Flagstaff in the snow. I figured out that my front Axle moved inward pulling out of the hub. I used a pry bar to check the Axle, it ended up being an easy fix. I don't know if this is helpful, but, what can I say.

 

[danno]

Welcome to TRS. I'm not well versed in the newer Rangers and the terminology people use. This may be a stupid question, but what does PVH stand for ? I had problems with my 97 in January, the 4wd went out on it while I was coming back from Flagstaff in the snow. I figured out that my front Axle moved inward pulling out of the hub. I used a pry bar to check the Axle, it ended up being an easy fix. I don't know if this is helpful, but, what can I say.

Thanks Shadowrider. PVH stands for pulse vacuum hubs. It was just ford's way of engaging/disengaging hubs on the fly from mid 90's to 2000, they are infamous for failing or being problematic. The weird thing about mine is doesn't have the vacuum set up, in fact it doesn't really have a locking hub at all. I feel like it has a '01 front end on it for some reason.. Which I believe locks the entire front axle in when 4wd is engaged instead of locking the hubs, but that doesn't make sense either for just one of the front tires spinning. so you can see my confusion, Ha.

That's interesting about your Front Axle pulling inward out of the hub. I didn't know that was even possible. but this might be a possibility for me since when I have all 4 wheels in the air and the truck in drive, I can feel the wheel that doesn't spin and feel like it wants to spin and I can help it along but it wont keep spinning by itself. I am thinking the problem has to be in the cv shaft/joints or in the axle/transfer case. I guess the only way to tell if something is broken is to start tearing those items apart. Not sure what you meant by "using a pry bar to check the axle" but I'd be curious to hear more.

 

[Roert42]

I know the later models, mine is an 03, has a live front axle. This mean the front hubs are always lock and the front differential is always turning. To test is yours is the same, when the truck is up off the wheels turn one of the front wheels. If the other front wheel turns, then you will know everything is connected.

if the other wheel spins the opposite direction you are turning your tire, then you have an open differential. With an open differential, it’s entirely possible to have one wheel turning and one wheel completely stopped. The wheel with the least traction gets all the power.

 

[dvdswan]

Welcome to the site. Albeit that you have a 4x4, it's not a 4x4. The basic 4wd vehicle has open differentials, meaning a one wheel wonder. This is true for both axles. So one tire has power to it on each axle.

Adding LSDs, lockers, or selectable lockers give power to each tire on each axle they are added to.

 

[danno]

Thanks Guys, I was doing a little more reading and figured I do have an open dif as you guys have suggested. This makes sense why I can stop one tire and the other keeps spinning when I have the vehicle off the ground. However, I am still confused since when under serious load (like being stuck in fairly deep snow on a hill) NEITHER front tire spins. Shouldn't the open diff set up mean that when in 4WD at least 1 front tire and 1 back tire are supposed to turn? In my case the front tires aren't spinning when it gets stuck. I would think at least one of the front tires should be digging in this case? is there a reason for this? or is it just the nature of the differential system?

 

[MikeG]

Unless the transfer case has a center differential (don't think so but some older trucks did I believe, back in the dark ages) then yes one front tire really ought to be spinning. Sounds like something broke/disengaged.

 

[dvdswan]

Unless the transfer case has a center differential (don't think so but some older trucks did I believe, back in the dark ages) then yes one front tire really ought to be spinning. Sounds like something broke/disengaged.

This is true if the vehicle is a AWD or an auto select 4WD system. Until the vehicle is actually switched into 4HI or 4LO it will act like that.

@danno if this is your case, you are in 4HI or LO and the front tires are not spinning but the rear one is then as @MikeG said, "something broke/disengaged".

With the vehicle on jack stands, t/case in 4HI or 4LO, can you turn the front driveline freely, meaning rear does not turn, if it does then place the rear on the ground and attempt to turn the front driveline, if it does not turn then your t/case is probably good. move to the front axle. take it out of 4HI or 4LO. turn front drive line both tires will turn, chock one tire free tire should turn, chock both wheels attempt to turn, if it turns one or both of the hubs are bad if the axles don't spin then you have an issue with your differential.

 

[Shadowrider6661]

Raise the front wheels off the ground and rotate your front driveshaft by hand while not in 4 hi or 4lo and with transmission in neutral. This will allow you to see if your front diff is rotating the front axles, if your axles are rotating, your Differential should be fine. Next, block one front wheel at a time and turn the driveshaft to see if each wheel is engaging. Make sure you try and hand rotate each wheel to see if the driveshaft is also rotating. This should tell you if your hubs are the problem. Next, put transmission in gear and engage transfer case and see if you can rotate the driveshaft. If the driveshaft won't turn, the transfer case is working. If you can turn the driveshaft, transfer case is bad. These are not in any specific order for how you check you system, I am just giving you an idea on how I would check my trucks front end. I'm sure that others will give you more or different suggestions on how to proceed. Ultimately, its up to you to take all the info and do as you see fit. I hope you can get this problem resolved without too much aggravation. Have a great day.

 

[4x4junkie]

Thanks Shadowrider. PVH stands for pulse vacuum hubs. It was just ford's way of engaging/disengaging hubs on the fly from mid 90's to 2000, they are infamous for failing or being problematic. The weird thing about mine is doesn't have the vacuum set up, in fact it doesn't really have a locking hub at all. I feel like it has a '01 front end on it for some reason.. Which I believe locks the entire front axle in when 4wd is engaged instead of locking the hubs, but that doesn't make sense either for just one of the front tires spinning. so you can see my confusion, Ha.

You mentioned your truck was built Feb 2000... All '00 model trucks after a certain build date (I think 12-'99, but don't quote me on that) did get the later live spindle hubs. So yes, probably easiest to treat the front hubs, rotors & the like as if you have a 2001 model.

Next, put transmission in gear and engage transfer case and see if you can rotate the driveshaft. If the driveshaft won't turn, the transfer case is working.

Be sure the front wheels are still up off the ground when you do this part, otherwise (provided the front differential and axle as a whole are in working order) the driveshaft won't turn regardless of whether the transfer case is properly engaged or not.