Clunking while in 4wd going up hills

[osujason]

I have a 2003 Ford Ranger Fx4 Level II with an automatic transmission. The 4wd system seems to work properly until you start to go up any moderate to steep hills putting additional load on the system. This is when a loud clunking/slipping starts to happen every 5-10 seconds. The first time it did this, I thought something was about to break, but here we are a year later and still doing the same thing as I have learned to avoid steep hills where 4wd is required. It's very annoying though.

Since it started doing this, I have had the transmission and transfer case both rebuilt. The front drives shaft has been swapped out twice and u joints replaced, front diff has been inspected and looks good, suspension has been looked at as well. So after all that, the clunking/slipping still happens in 4wd while going up hills.

What else could be causing this? Thanks in advance for any advice.

JB

 

[Grumpaw]

Welcome...
As you will learn, you have joined a forum of Ranger nuts and misfits (well, some of us), and like to give solid advice.
When no solid advice is known, you will get some stright forward totally off the wall answers...
So I'll go first....
Very simple to correct your problem....
JUST DRIVE DOWN HILLS !!! Problem solved.

(I;m sure someone will join in with some real help)

 

[osujason]

Thanks! I have been a reader of this site for the last 2 years and have found it very helpful in regards to my ranger.

 

[Grumpaw]

2 years ??? And you haven't joined in the fun...shame on you !!!

 

[osujason]

I know, ive been missing out! I figured i had better join though because i would prefer to use my Ranger to its full potential and its current 4wd abilities are limited when going uphills.

 

[Eddo Rogue]

Do you mean going uphill while steering? If so, it might be the u joint knuckles rubbing while spinning and turning at the same time, due to the excessive amounts of steel around u joints. The fix is to grind em down a bit where it could use more clearance. Pretty sure there's a how to tech article and some threads around here somewhere...

 

[osujason]

I only notice the clunking/slipping going in a straight line uphill in 4wd. I haven't tried turning the steering wheel when this was happening.

 

[Eddo Rogue]

Interesting, usually the clunking is only when steering....Have you checked your hubs? They might be struggling to grab.

 

[MikeG]

Hubs and CV / ujoints in the front drive shafts are about all you have left.

 

[osujason]

Thats what im thinking, but if i understand correctly, my 2003 ranger would have a live front axle so there wouldn't be an obvious"locking hub" that could fail. I suppose bearings in the hub could be going bad but i haven't noticed any play in the front wheels. I will look into hubs further though.

 

[osujason]

Hubs and CV / ujoints in the front drive shafts are about all you have left.

Yeah, i am going to look further into Hubs, CV/ujoints. Ive already looked at them somewhat but didn't really notice anything at the time.

 

[pjtoledo]

experiment time.

put it in 4wd, drive slow with a heavy foot on the brakes to simulate load.

what happens?


if results are inconclusive try a "crude" experiment: park on dirt and chain it to a tree, 4wd lo and see what happens.

since we are like totally environmentally responsible guys, be sure to use a strap around the tree


(and stop the experiment if the tree starts to fall)

 

[fixizin]

Well, per @Grumpaw, I'm going to be the wingnut/misfit, and suggest a major conversion to The Dreaded Pulse Vacuum Hub (PVH) system... not only will you get better MPGs when NOT in 4WD, but I once pulled out a tree stump with my PVH system--4LO, in Reverse, using those beefy TOW HOOKS up front--and NO UPHILL CLUNKING afterwards, lol...

Seriously though, how many clunks per wheel rotation would you say you're hearing/feeling? That would be a clue as to which link in the chain is breaking down.

 

[osujason]

experiment time.

put it in 4wd, drive slow with a heavy foot on the brakes to simulate load.

what happens?


if results are inconclusive try a "crude" experiment: park on dirt and chain it to a tree, 4wd lo and see what happens.

since we are like totally environmentally responsible guys, be sure to use a strap around the tree


(and stop the experiment if the tree starts to fall)

I'll give this a shot this weekend. I would expect the clunking/slipping to be replicated, but we shall see. I'll provide an update this weekend.

 

[osujason]

Well, per @Grumpaw, I'm going to be the wingnut/misfit, and suggest a major conversion to The Dreaded Pulse Vacuum Hub (PVH) system... not only will you get better MPGs when NOT in 4WD, but I once pulled out a tree stump with my PVH system--4LO, in Reverse, using those beefy TOW HOOKS up front--and NO UPHILL CLUNKING afterwards, lol...

Seriously though, how many clunks per wheel rotation would you say you're hearing/feeling? That would be a clue as to which link in the chain is breaking down.

Im not sure on the exact clunks per wheel rotation yet, but im going to work on it this weekend. It seems like I'm usually moving 5-8 mphs and i hear the clunk every 5 to 10 seconds. I suppose that could be one clunk per rotation.